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Biomedical subjects

L Merlo

Publications and source records attributed to L Merlo.

At least 19 recordsLinked to original sources
PubMed1994

[Applications of digital radiology to pediatric uroradiology].

The authors report their 4 years' experience with a computerized digital radiographic system based on photostimulable phosphor plates which was used mostly in pediatric radiology. Major protection advantages were observed for uroradiology where high kV (90-95 kV) and very low exposure times (0.02-0.010s) were used. With this radiographic technique reduced exposure parallels increased graininess due to quantum mottle: the two variables must therefore be balanced not to decrease diagnostic accuracy. During our 4 years' experience, 368 examinations were performed on pediatric patients: 252 micturition cystourethographs, 81 urograms and 35 retrograde pyelographs. None of these examinations needed to be repeated due to over/under-exposure and image quality was always high, in spite of a light "noise". Digital radiography in pediatric urology allows radiation dose to be reduced and high quality images to be acquired and is therefore likely to take over conventional radiologic techniques.

Adolescent↗
PubMed1992

[Multidirectional instabilities and hyperlaxity of the shoulder].

Multidirectional instability is an unusual entity which is frequently missed in the context of unstable shoulder. The diagnosis of this condition may be difficult and is based on demonstration of basic anatomical lesions, usually acquired: capsular distension and damage to the inferior glenohumeral ligament responsible for the inferior component of the instability. Despite a suggestive clinical history, the positive diagnosis is based on a very detailed clinical and radiological examination, performed under general anaesthesia if necessary, in order to define the preferential direction of instability. Conventional and CT arthrography are of undeniable diagnostic and therapeutic value in the context of assessment. First-line treatment should be conservative. When surgery is indicated, it may consist of a combination of bone grafts and capsulorraphy, as described by C.S. Neer.

Humans↗
PubMed1992

[Bipolar prosthesis in femoral neck fractures. Results and long-term acetabular tolerance of 36 bipolar arthroplasties].

The authors present the long-term results of 36 SEM cemented bipolar hip prostheses for femoral neck fractures with a mean observation time of 7.4 years. The objective was to study the acetabular tolerance of these prostheses comparing with Moore's and Thompson's conventional hemiarthroplasties. The average age of the patients was of 69 years. According to the Merle d'Aubigné's classification, clinical results were better than those results reported in the literature with conventional hemiarthroplasties. At long term, acetabular deteriorations were nevertheless frequent (41.6 per cent pinchings and 25 per cent protrusions), but with no clinical significative correlation. They seem to be favoured by technical errors (drilling, size of the cups) and acetabular morphology. The part of the intermediary joint's mobility is difficult to demonstrate and is far being univocal. The authors conclude, to the superiority of the bipolar hip prosthesis actually totalizable (long term clinical results and middle term acetabular tolerance) in comparison with the conventional hemiarthroplasties, and recommend the use of those implants in sub-capital displaced femoral neck fractures for elderly patients with no arthrosis.

Acetabulum↗
PubMed1991

Diagnostic potential of double contrast arthrography of the knee with the digital technique.

Experience with digital radiography applied to double contrast arthrography of the knee performed with a photostimulable phosphor plate is reported. The image processing technique used to improve the digital image is described, and some theoretical considerations are discussed. A preliminary comparison is also made between arthrographic images obtained with conventional screen-film systems and the digital system, especially in respect of the image quality and visualization of the soft tissue structures least well demonstrated with conventional arthrography.

Arthrography↗
PubMed1991

Computed radiography in neonatal intensive care.

The Authors report their experience in the employment of a computerized digital radiographic system in Neonatal Intensive Care. The analog screen-film system is replaced by photosensitive imaging plates, scanned after X-ray exposure by a laser that releases the digital image, which can then be manipulated on computer work-stations. In a period of twelve months about 200 chest-abdomen X-ray examinations in Neonatal Intensive Care have been performed using this method with good technical and diagnostic results. The use of digital radiography in the neonatal area is of high interest: this system produces good quality images, there is a reduction in radiation dose and 'retakes', the system allows selective enhancement of different structures and their magnification.

Humans↗
PubMed1990

Development of dopaminergic drugs for the chronic treatment of congestive heart failure.

1. The search of orally active dopaminergic drugs for the chronic treatment of congestive heart failure has followed two different approaches. 2. On the one hand, a selective DA-1 receptor agonist, such as fenoldopam, has been investigated as an agent developed for the stimulation of vascular and tubular DA-1 receptors in the kidney. On the other hand, orally active prodrugs were synthetized with the aim of mimicking the full pattern of dopaminergic and adrenergic actions of intravenous dopamine. 3. Ibopamine, the diisobutyric ester of N-methyldopamine, has shown effects comparable to those of dopamine in various animal models and in clinical investigations. Furthermore, patients suffering from mild or severe congestive heart failure were shown to benefit from ibopamine treatment in a number of therapeutic trials. 4. Limited experience is currently available on other prodrugs, such as docarpamine and Sim 2055, i.e. the 4-0-phosphate ester of N-methyldopamine. The latter is an analogue of ibopamine designed for a preferential delivery of N-methyldopamine in the kidney. 5. Based upon some additional studies with levodopa, the results suggest that a combination of DA-1 and DA-2 agonistic activity is a desirable feature of a new drug, since it appears suitable to provide vasodilation while counteracting the neurohumoral abnormality of congestive heart failure.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1990

Digital radiography versus conventional radiography during excretory urography: our experience.

The authors describe a computed radiographic system employed to generate and archive digital images in intravenous urography. For each exposure the system produces two digital images: the first (left image) simulates a conventional screen-film radiograph, the second (right image); enhances some spatial frequencies and emphasizes the margins of the structures. These images can be modified in their chief parameters and then printed by a laser-printer and archived on optical disks. Four experienced radiologists evaluated digital images with regard to some chief diagnostic parameters and, in 50 patients, they compared digital images with conventional screen-film radiographs and submitted the results to statistical analysis. For some of the chosen parameters, particularly for the evaluation of renal margins before and after contrast medium injection, digital images gave statistically better results than conventional films, while, no statistically significant different was observed for the other parameters. From the results of this preliminary study digital radiography was found to be useful in intravenous urography by reducing the patient's exposition dose, by always obtaining images of good quality, and by enhancing some particular features of the standard image; on the other hand there were many unsolved problems regarding the communicating and archiving system (PACS), because of the slowness of the image transfer procedure, difficulties in data transmission and complexity of referential procedures.

Evaluation Studies as Topic↗
PubMed1990

[Digital radiography in neonatal intensive care].

The authors report their experience with the routinary use of a computerized digital radiography system in Intensive Neonatal Care department. The conventional screen-film system is replaced by photostimulable imaging plates, which are scanned during processing by a laser providing the digital image. The latter is subsequently processable on high-resolution monitors. Over a 6-month period 86 examinations were performed with this method in Intensive Neonatal Care; good technical results were obtained. The use of digital radiography in intensive neonatal care is extremely promising for it allows high-quality images to be obtained, and radiation dose and number of acquisitions to be reduced. Finally, work stations allow both selective visualization of different body structures and their magnification.

Humans↗
PubMed1990

[Traditional and digital urography compared. The authors' own experience].

A computed radiographic system for generating and archiving digital radiographic images was employed in ivp. The system produces 2 digital images per exposure: the first one simulates a conventional radiograph, while the second enhances some spatial frequencies and emphasizes the structure borders. The conventional radiographs and the digital images of 50 patients submitted to ivp were reviewed by four experienced radiologists to evaluate their comparative quality, and the results were statistically analyzed. Digital images proved to be better than conventional radiographs for some of the selected parameters, especially in the evaluation of renal edges and sometimes for calyceal opacification. As for the other parameters, no statistically significant difference was observed between conventional radiographs and digital images.

Adult↗
PubMed1989

Acute haemodynamic effects of ibopamine and dopamine on isovolumic relaxation.

The effects of intraduodenal ibopamine (a new orally active inotropic agent claimed to have haemodynamic effects similar to dopamine) on isovolumic relaxation were monitored for 90 min in eight closed-chest anaesthetized dogs. Dopamine and epinine (ibopamine active metabolite) were also infused at graded doses. After 15 min, ibopamine (12 mg/kg) shortened the time constant of isovolumic relaxation, and increased stroke volume and mean aortic pressure. Peak positive dP/dt increased significantly only 10 min later. Heart rate did not change. Dopamine (10 micrograms/kg per min) similarly reduced the time constant, and increased stroke volume, mean aortic pressure, peak positive dP/dt and heart rate. Epinine (10 micrograms/kg per min) caused similar changes in peak positive dP/dt, stroke volume, mean aortic pressure, and accelerated time constant without raising the heart rate. Ibopamine and epinine therefore significantly improved the isovolumic relaxation phase, like dopamine, without however affecting the heart rate.

Animals↗
PubMed1989

Conservative management of urinary abnormalities detected in utero.

During a 5-year period, we observed 48 fetuses with urinary malformations diagnosed by antenatal sonography. Postnatal investigations confirmed the presence of a urinary tract anomaly in 44 of the 48 fetuses selected by prenatal ultrasound (91%). Accurate antenatal diagnosis was made in 35 of the 48 cases (73%). In 9 fetuses renal disease was detected, but its specific nature was not in accordance with the prenatal diagnosis. In our series the most common anomaly was hydronephrosis secondary to ureteropelvic junction obstruction. This condition was observed in 31 of the 44 patients (70.4%); 7 of the newborns who showed an obstructive pattern were submitted to early surgical repair, while the remaining 24 cases and 1 renal unit of the group undergoing early surgical repair were relegated to expectant observation, with periodic clinical and laboratory controls. A spontaneous recovery was observed in 12 cases; the dilatation remained unchanged in 10 cases, while 3 patients showed a progressive worsening of the condition which led to a surgical correction. Our findings agree with those in recent reports in providing little support for early, indiscriminate surgical repair. Moreover, our experience confirms the possibility of a spontaneous recovery in newborns with hydronephrosis and draws attention to the benefit of a conservative management in properly selected patients.

Female↗
PubMed1989

Cardiovascular and renal action of dopaminergic prodrugs.

The possibility of exploiting the cardiovascular and renal action of dopamine for therapeutic purposes is enhanced by its conversion into orally active prodrugs. Following an outline of the medicinal chemistry bases of the development of these prodrugs, laboratory and clinical pharmacology of ibopamine, levodopa, gludopa, and TA-870 are reviewed, pointing out the interesting indications of various preliminary studies in heart failure, essential hypertension, and renal failure on the one hand, and the extensive therapeutic experience with ibopamine as an "inodilator" in the chronic treatment of congestive heart failure on the other hand. New experimental results are also reported for ibopamine and for the novel prodrug Sim 2055, i.e., epinine-4-O-phosphate. The latter is shown to act as a selective renal vasodilator on oral administration in dogs and it is therefore proposed for clinical investigation in renal failure and in essential hypertension.

Animals↗
PubMed1989

[Double-contrast arthrography in meniscal pathology. Remarks on 1000 cases].

The authors performed a statistical study on a series of 1000 patients examined with double-contrast fluoroscopically-guided knee arthrography. Arthrographic diagnoses were compared with the arthrotomic (500 patients), arthroscopic (350 patients) or clinical diagnoses of 150 patients with a follow-up of 6 months. In this series of patients with a history of "recurrent meniscal injury", arthrographic diagnoses were confirmed in a high percentage of cases, with 96.9% accuracy, 96.7% sensitivity for tears, and 98.6% specificity. On the basis of these results the authors suggest double-contrast arthrography as an examination of considerable value in the diagnosis of meniscal lesions, while in their opinion arthroscopy should be limited to questionable cases, to complex lesions with involvement of multiple articular structure and to the alterations clearly treatable by arthroscopy.

Arthrography↗
PubMed1987

Pharmacological characterization of epinine 3-O-sulphate and 4-O-sulphate.

Ibopamine, the diisobutyric ester of N-methyldopamine, is able to increase cardiac output and induce vasodilatation on oral administration. While the pharmacodynamic activity of ibopamine is rather long-lasting, N-methyldopamine, i.e. ibopamine's primary metabolite, can be detected in plasma only for a short time after the administration. We have investigated the pharmacological activity of N-methyldopamine 3-O-sulphate and 4-O-sulphate, since the plasma levels of these conjugated metabolites are higher and last longer than those of N-methyldopamine. These compounds appeared to be devoid of any pharmacodynamic activity both in vivo on the main hemodynamic parameters in dog and on diuresis in rat, and in vitro on cat papillary muscle and rabbit ear artery. Consequently, the duration of ibopamine hemodynamic effects cannot be related to these circulating metabolites, thus other hypotheses should be taken into consideration.

Animals↗