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Biomedical subjects

L Piret

Publications and source records attributed to L Piret.

At least 19 recordsLinked to original sources
PubMed1992

Influence of ureteral status on kidney washout during technetium-99m-DTPA diuresis renography in children.

To assess the influence of the ureter on renal washout during 99mTc-DTPA diuresis renography, ureteral images were reviewed in 42 children (median age: 5 mo) referred for hydronephrosis. Sixty-minute acquisitions were obtained in hydrated patients under bladder drainage. Furosemide was injected at 30 min. An abnormal ureter was defined as an intense and continuous image of greater than 10 min. A washout index was determined on renal (KT1/2) and ureteral (UT1/2) curves. Curve patterns corresponding to normal (type I), obstructive (II) and nonobstructive (III) cases were described. Compared with the x-ray data, diuresis renography was highly sensitive (91%) and specific (98%) for detecting any abnormality. Despite an obstructive KT1/2 (greater than 20 min), no patient with an abnormal ureter underwent therapy at the ureteropelvic junction. After surgery at the lower level, hydronephrosis regressed. Our data indicate that abnormal ureter findings at diuresis renography have to be recognized before planning therapy for children with hydronephrosis.

Adolescent↗
PubMed1990

Familial phaeochromocytoma: successful treatment with 131I-MIBG.

We report the case of a family in which the mother died of hypertensive encephalopathy following the relapse of a phaeochromocytoma. Two of her children are still alive. Both children had malignant phaeochromocytomas that have been treated by surgery and 131I-MIBG. The first child presented with phaeochromocytoma of the right suprarenal gland at the age of 7 years. Surgery was performed. At the age of 14 years, he developed a tumour of the left suprarenal gland and two pulmonary metastases demonstrated by 131I-MIBG. The three tumours were removed, but new lesions occurred. The boy then was treated with 200 mCi (7,400 MBq) of 131I-MIBG given twice, and is now free of disease more than 2 years after treatment. His sister presented at the age of 12 years with phaeochromocytoma of the left suprarenal gland, the only lesion recognized by 131I-MIBG. The tumour was removed, but 5 months later, she developed phaeochromocytoma in the right suprarenal gland. She was treated with 200 mCi (7,400 MBq) of 131I-MIBG and surgery was performed 6 months later. Histology of the suprarenal gland could not demonstrate the persistence of phaeochromocytoma cells. The child is now free of disease more than 2 years after treatment.

3-Iodobenzylguanidine↗
PubMed1988

Assessment of left ventricular diastolic function in patients receiving anthracycline therapy.

Abnormalities in left ventricular filling have been described as an early finding in coronary artery disease and in cardiomyopathy. The present study was undertaken to determine whether impaired diastolic function may be an early sign of anthracycline cardiotoxicity. Radionuclide left ventricular curves of 30 treated patients were compared with the curves of 17 normal, agematched, volunteers. The curves were analyzed for ejection fraction, peak filling rate (normalized for end diastolic counts and for stroke counts), time to peak filling rate and filling fraction in the first third of diastole normalized for cycle length. In 20 patients (Groups A and B), we analyzed the radionuclide ventriculography preceding the decrease of systolic function or a clinical congestive heart failure. In ten patients (Group C) who ended a treatment regimen without systolic dysfunction or clinically evident cardiotoxicity, we analyzed the ventriculography at the end of the therapy. Among the diastolic indexes, only the first third filling fraction was abnormal in a minority of the patients (6/20 in Groups A and B). Our findings suggest that diastolic dysfunction is uncommon in anthracycline treated patients prior to systolic dysfunction.

Adult↗
PubMed1988

Effect of molsidomine on the lung diffusing capacity of normal men.

Molsidomine (M) is a new antianginal drug which induces a peripheral venous pooling and decreases pulmonary artery and pulmonary venous pressures. The purpose of our study is to assess whether M influences the filling of the pulmonary capillary bed as estimated by the single-breath lung diffusing capacity (DLCO). DLCO was measured before and 10, 20, 30, 40, 50 and 60 minutes after sublingual administration of 2 mg molsidomine in six healthy men examined in sitting and supine positions. The blood flow distribution was estimated by means of radioactive xenon, in sitting position only, before and 30 minutes after M intake. M. induces a significant fall in DLCO from the 20th to the 60th minute which indicates an emptying of the pulmonary capillary bed. Concomitantly, blood flow is redistributed from the apices to the lung bases. We explain the decrease in DLCO by two mutually non-exclusive mechanisms: an outflow of the blood from the thorax to the periphery and a change in the lung-perfusion distribution. From a practical point of view, two conclusions may be reached. First, in coronary patients a decrease in DLCO and DLCO/VA may be due to the intake of vasodilating agents such as molsidomine and not to emphysema or lung fibrosis. Secondly, the measurement of DLCO is a useful tool to assess the action of a drug on the pulmonary circulation.

Adult↗
PubMed1985

The osteoinductive capacity of differently HCl-decalcified bone alloimplants.

Three procedures to obtain bone inductive implants were tested heterotopically in 3-month-old allogeneic rats: 1) antigen-extracted HCl-decalcified at 4 degrees C, autolysed implant (AAA bone); 2) HCl-decalcified implant at 4 degrees C; 3) HCl-decalcified implant at room temperature. Each type of implant was either deep-frozen at -35 degrees C for at least 2 months or immediately freeze-dried. The bone inductive capacity of the differently HCl-decalcified cortical bone implant was evaluated at 2 months by isotopic strontium incorporation and by ash-weight measurements. Bone HCl-decalcification alone, either at 4 degrees C or at room temperature, gave a higher new bone yield than the freeze-dried AAA bone. The type or short-term preservation technique had no effect on the osteoinductive capacity of either of the differently treated implants, AAA bone expected.

Animals↗
PubMed1983

Pulmonary vascular tone is a determinant of basal lung perfusion in normal seated subjects.

In the human upright lung the downward increase in lung perfusion reverses in the lower third, thus giving rise to a zone of reduced basal perfusion (zone 4). The flow in zone 4 is regulated by the extra-alveolar vessels, the diameter of which is determined by lung volume, perivascular interstitial pressure, and vasomotor tone. To estimate the role of pulmonary vascular tone in the formation of zone 4, we infused nitroprusside (NTP), a potent pulmonary vasodilator, in six normal seated subjects. We measured their regional perfusion distribution using 133Xe in control conditions and at two dose levels of NTP (20.8 and 52.1 micrograms/min). Regional perfusion distribution was measured similarly and according to the same protocol in six subjects receiving only a placebo solution. In four of the six subjects receiving NTP, right-heart catheterization allowed simultaneous estimations of cardiac output and pulmonary arterial pressure to be made. NTP slightly decreased the perfusion of the nondependent parts of the lungs and markedly increased the perfusion of the lung bases, thus reducing the extent of zone 4. No changes were observed in the placebo experiments. Cardiac output and indices of ventilation and gas exchange did not change significantly. Peripheral and pulmonary arterial pressure fell slightly but significantly during NTP infusion. We attribute the observed changes in basal perfusion to the vasodilatory effects of NTP on the extra-alveolar vessels. Our findings thus support the hypothesis that in normal subjects zone 4 is partly created by the pulmonary vascular tone.

Adult↗
PubMed1982

Effect of age on the regional perfusion and washouts of injected xenon in normal men.

The aim of this work was to localize the alveoli with low ventilation-perfusion ratio which are responsible for the age related increase of the ideal alveolar-arterial O2 partial pressure difference. For this purpose, we measured: (1) the washouts of perfused 133 Xenon (Xe) in the whole lung and in 6 horizontal slices of the right lung, and (2) the topographical distribution of perfusion (Qi) in 27 healthy, non-smoking seated men, between 18 and 65 years. The distribution of Qi is unaffected by age. The global and regional washouts slowed with age, the trends being the same in the 6 investigated regions. This data was interpreted as indicating that in our subjects the low VA/Q units are not situated predominantly at the base, but are scattered throughout the lung.

Adult↗
PubMed1982

Effect of nitroglycerin on pulmonary perfusion distribution and gas exchange of normal subjects.

In eight healthy subjects we assessed the effects of 3 mg sublingual nitroglycerin on lung distribution of ventilation and perfusion using 133Xe (sitting, supine and lateral decubitus) and on alveolo-arterial O2 and CO2 partial pressure differences [(PAO2-PaO2), (PaCO2-PACO2)] and physiological dead space to tidal volume ratio (VD/VT) (sitting). In all studied positions, nitroglycerin induced a significant decrease in uppermost perfusion indices, and a significant increase in dependent perfusion indices, without changing the distribution of ventilation. Significant increases in (PaCO2-PACO2) and VD/VT were observed up to 60 min after nitroglycerin. No changes in (PAO2-PaO2) occurred, except for a transient decrease due to transient hyperventilation following nitroglycerin. The redistribution of pulmonary perfusion after nitroglycerin may be attributed to the passive effects of lowered pulmonary vascular pressures, and to possible action on extra-alveolar vessels. The evolution of the indices of pulmonary gas exchange is compatible with the observed redistribution of ventilation/perfusion relationships.

Adult↗
PubMed1982

Effect of nitroglycerin on DL of normal subjects at rest and during exercise.

By use of the single-breath diffusing capacity for carbon monoxide (DL) as an index of the pulmonary capillary filling, the effects of 3 mg sublingual nitroglycerin (NTG) were studied in eight healthy subjects at rest and during exercise. At rest, NTG induced a significant and persistent decrease of DL when subjects were sitting or supine (60 min of observation) and also when they were in the lateral decubitus or supine with legs up position (30 min of observation). Subjects in the supine positions showed more pronounced percentage decreases in DL than when sitting. In the sitting position 1 mg NTG also induces a decrease of DL. During a moderate upright cycloergometer exercise, NTG also induces a significant decrease of DL; the decrease is smaller and of shorter duration (less than 15 min) than at rest, but it reappears as soon as the exercise is stopped. The decrease of DL may be attributed to an outward shift of blood from the thorax to the periphery or to a redistribution of lung perfusion consequent to changes in pulmonary vascular pressures.

Adult↗
PubMed1980

Tc-99m-diethyl-IDA imaging: clinical evaluation in jaundiced patients.

Hepatobiliary imaging with Tc-99m-N,alpha-(2,6-diethylacetanilide)-iminodiacetic acid (Tc-diethyl-IDA) was performed in 91 jaundiced patients with documented hepatobiliary damage and serum total bilirubin up to 35 mg/dl. There were 56 patients with obstructive jaundice and 35 with hepatocellular disease. Correct discrimination between hepatocellular and obstructive jaundice was possible with an overall accuracy of 90%. Agreement with the final clinical diagnosis was obtained in 97% of patients with hepatocellular disease, and in 86% of patients with obstructive jaundice. The reliability of the test was inversely related to the serum bilirubin concentration. The incidence of true-positive scans dropped from 93% for bilirubin levels below 10 mg/dl to 83% for bilirubin between 10 and 20 mg/dl. Above 20 mg/dl, the demonstration of a mechanical obstruction was possible in only one out of the four patients with obstructive jaundice. The high predictive values of the test illustrate that Tc-diethyl-IDA imaging constitutes a reliable method to demonstrate an obstructive cause for the jaundice as long as the bilirubin level remains below 20 mg/dl.

Bilirubin↗
PubMed1978

Even distribution of 133Xe bolus inhaled at residual volume in healthy subjects.

We selected from among 46 healthy students (22 to 31-yr-old) 7 subjects (group A) in whom the normalized height of phase IV (height of phase IV/phase IIIx100), after inhaling a bolus of He at RV, was very small (10%). We compared them with 6 subjects (group B) selected on the basis of a tall phase IV (78%, A vs. P P less than 0.005). Age and height were comparable, but weight was lower (P less than 0.05) and RV/TLC ratio (but not other spirographic indices) was larger (P less than 0.025) in group A. The average amplitude of cardiac oscillations was 4 times higher in group B (P less than 0.005). He closing volume, but not closing capacity was less in group A (P less than 0.05). A bolus of 133Xe inhaled at RV was nearly uniformly distributed in group A while producing a large vertical gradient in group B. The difference between groups A and B may reflect a difference in the mechanical properties of the chest wall leading to a less complete empting of the lung in the former group.

Adult↗
PubMed1978

Clinical evaluation of Tc-99m-diethyl-IDA in hepatobiliary disorders.

N,alpha(2,6-diethylacetanilide)-iminodiacetic acid is a new Tc-99m-labeled radiopharmaceutical primarily excreted through the biliary tract. Its high concentration in the bile allows the imaging of the biliary tree and the gallbladder. Scintigraphic studies were performed in 20 normal subjects and 42 patients suffering from various hepatobiliary disturbances. In normal subjects, the early liver uptake was followed by the accumulation of the tracer in the intrahepatic bile ducts and the gallbladder before its discharge into the duodenum. In cases of hepatocellar damage, the hepatic accumulation of the tracer was clearly depressed. Any acute or subacute disorder of the gallbladder was clearly demonstrated by Tc-99m-diethyl-IDA. In cases of asymptomatic cholelithiasis, we observed delayed visualization of the gallbladder associated with its decreased accumulation of the tracer. The intrahepatic bile ducts were distended in cases of incomplete obstruction of the hepatobiliary ducts, whereas they were never visualized when there was severe hepatocellular damage or complete obstruction of the biliary tree.

Bile Ducts, Intrahepatic↗
PubMed1978

Unusual features of thyroid function in anterior pituitary failure.

Endocrinological studies have been performed in 40 cases of adult hypopituitarism. In 5 cases, unusual features of thyroid function were observed, characterized by the coexistence of low levels of circulating thyroid hormones with a normal thyroid uptake and in 4 cases, a significant secretion of TSH.

Adult↗
PubMed1975

Detection of skeletal involvement in Hodgkin's disease: a comparison of radiography, bone scanning and bone marrow biopsy in 38 patients.

As part of the staging of 38 patients with Hodgkin's disease seen over an 18-month period, we have used radioisotopic scanning of bone, as well as radiography and bone marrow biopsy, in an attempt to assess osseous and bone marrow involvement. Of the 38 patients, 14 were found to have skeletal involvement. In 11 this was histologically proved. In 8 patients, the radioisotopic scan first raised the suspicion of localized bone involvement, which was subsequently proved by bone marrow biopsy or by radiography. We believe that bone marrow involvement may at times be localized when patients with Hodgkin's disease are first staged and may precede local osseous involvement. If this is so, a reasonable approach to the search for bone marrow or osseous involvement would be to start with a bone scan and to follow this with a bone marrow biopsy from the suspicious area or a careful radiography of the same site; the latter is important if the site of increased uptake of the radionuclide is inaccessible to the biopsy needle.

Adolescent↗