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Biomedical subjects

P Beaufils

Publications and source records attributed to P Beaufils.

At least 19 recordsLinked to original sources
PubMed1992

Improvement of digital coronary angiography: high resolution processing coupled with a real time functional synchronization procedure.

The use of Digital Subtraction Angiography in coronary applications is restricted by the difficulty in: 1. Obtaining a good resolution of the distal branches. 2. Avoiding, for the purpose of subtraction, the motion artifacts induced by artery and background displacement during the cardiac and respiratory cycles. 3. Preserving the dynamic vascular motion. 4. And storing the digital dynamic information on a permanent support. We used for this study an angiography system, based upon a high resolution 45 MIPS-32 Mbyte image processor, interfaced with a 2.75 Gbyte Winchester drive allowing the real time storage of either 30 frames/s in the 512*512*8 bits matrix or of 7.5 f/s in the 1024*1024*8 bits matrix. To preserve the most important dynamic informations on the basis of the 7.5 f/s maximal storage rate, we developed a synchronization device able to recognize in real time, from chronologic delays derived by using both ECG and Aortic Pressure curves, the functional End-Diastolic (ED) and the End-Systolic (ES) positions, even in the case of heart rates varying during the procedure. The ED and the ES images are stored together with the Mid-Systolic (MS), the 1/3-Diastolic (1/3D) and 2/3-Diastolic (2/3D) images. To establish the validity of this sampling method, which uses a reduced number of frames per cardiac cycle, 7200 coronary injections performed during 450 routine coronary angiographies were compared by two independent observers (A and B), using: first a Digital (D) 5 frames/cycle sequence, and secondly a cine Film (F) 50 frames/s sequence acquired immediately after the corresponding D injection. The D technique resulted in the best image and diagnostic quality, particularly when the F quality was estimated 'fair' or 'poor' by both observers, and in an important reduction on X-Ray doses. The visualisation of the sequential ED, MS, ES, 1/3D and 2/3D frames gives the possibility: 1. of saving the dynamic information, as a regular sample of functional images can be displayed with a cine loop technique. 2. of facilitating cardiac synchronized subtractions. 3. of reducing the amount of frames per cycle, thus allowing an important reduction of X-ray doses and the digital and permanent storage of the most important cardiac cycles.

Angiography, Digital Subtraction↗
PubMed1992

[Meniscal injury in the plastic reconstruction of the anterior cruciate ligament. Meniscal suture or abstention].

The purpose of this study was to observe the change of the meniscal lesions, which are conservable by suture or simply by leaving-in-place within the frame of operated anterior instability. Forty-six knees which had been operated by the free transplant of bone-patellar tendon-bone, presented the associated lesions of conservable meniscus. These lesions were treated by suture of the meniscus in 15 cases and left in place in 31 cases. The programme of rehabilitation was the same in the two groups. All the patients have been followed-up for 26 months in average (12-40 months). In the group of meniscal suture, only one secondary meniscectomy was carried out. 8 patients presented moderate pain on the corresponding femorotibial joint line and 5/13 of the sportive patients recovered to the same level of activity. In the group of leaving-in-place, no meniscectomy has been carried out. Only 4 patients complained of pain and 23/27 recovered to the same activity level. The arthrographic and arthroscopic observations have been carried out in 23 cases. They confirmed the cicatrization of the sutured meniscus but also showed the possibility of total or partial cicatrization of the lesions left in place (12 on 13). The authors conclude that the peripheral meniscal lesions associated with the operation of the chronic anterior instability do not always require suture. The abstention on the meniscal lesion is possible if it is limited on the posterior segment: Then the functional results seem better.

Adolescent↗
PubMed1992

[Arthroscopic internal meniscectomy in patients over 55 years of age. Results over more than 4 years].

Fifty-one meniscectomies by arthroscopy were realised on patients of more than 55 years of age between 1981 and 1986. Twenty-four patients were reviewed after at least 4 years of follow up, 12 of them after a 7.5 years follow up. 21 results were noted as functionally very good or good, 3 were poor. The radiological analysis of femoro-tibial compartments in comparison with the non operative side showed a clear pejorative difference in one case, moderate in 5 without incriminating the morphological type. If the quality of result does'nt correlate with age, it was'nt the same for the type of lesion seen during arthroscopy, the best results after arthroscopic meniscectomies were seen in traumatic lesions occurring on normal menisci or on degenerative ones. The authors concluded that medial meniscectomy in patients older than 55 years is justified in precise indications: a known traumatism or also acute medial pain, or speedy with normal or subnormal X-ray and after a positive arthrography.

Aged↗
PubMed1991

Temperature-jump method for studying the fast transport of Na+ by (221) C10-cryptand across lipid membranes.

The kinetics of Na+ transport by (221)C10-cryptand through thin lipid membranes were determined by performing temperature-jump relaxation experiments on large unilamellar vesicles (L.U.V.) loaded with a fluorescent pH indicator. Applying temperature jumps of 4 to 7 degrees C to liposomes having phosphate as internal buffer and Tris as external buffer resulted in transmembrane delta pH's of about 0.104 to 0.182. After a temperature-jump, a decay in the delta pH was observed which corresponded to a Na+/H+ exchange occurring through membranes in the simultaneous presence of the cryptand and a proton carrier. The transport of Na+ ions by (221)C10 was found to be a fast kinetic process. Its initial rate increased with both the temperature and the cryptand concentrations. In addition, the temperature-induced changes in the apparent rate constants of the translocation of Na+ by (221)C10 were carrier concentration-dependent, and the apparent activation energy required to activate the transport decreased significantly with increasing cryptand concentrations. The results are discussed in terms of the structural, physico-chemical and electrical characteristics of carriers and complexes.

Biological Transport↗
PubMed1991

[Arthroscopy of the shoulder with the patient in beach-chair position].

The authors describe a technique of arthroscopy in the "beach chair" position, that they have exclusively used since 1989. The classical setting in lateral decubitus takes a long time and can be the cause of complications especially neurological due to the traction. In the chair position, the vision of the intraarticular structures is identical to the lateral position, and the absence of traction avoid the neurological complication. Another advantage is the quick and easy setting; the locoregional anesthesia is easy to use, it is possible to practice an open surgery without changing the setting. All these advantages lead the authors to propose this position for all arthroscopy of the shoulder whether diagnostic or therapeutic.

Arthroscopy↗
PubMed1979

[Acute myocarditis simulating myocardial infarct with regressive heart failure].

Two patients were hospitalised with severe heart failure and hypotension thought initially to be due to acute anterior myocardial infarction because of very suggestive electrocardiographic appearances. Heart failure rapidly regressed in both cases. The young age of these two patients, the pyrexia, rapid and total regression of the ECG appearances, the absence of atheromatous lesions at coronary angiography and clinical cure with a follow-up of 10 years in one of the cases, were factors in favour of the diagnosis of acute myocarditis.

Adult↗
PubMed1979

Relationships between hemodynamic profiles and topography of acute myocardial infarction.

Initial hemodynamics were studied in 101 patients with acute myocardial infarction complicated by shock or left heart failure. 59 had anterior myocardial infarction (AMI); 42 had inferior myocardial infarction (IMI). Data were processed by univariate analysis and correspondence analysis. AMIs and IMIs were significantly different on conduction disturbances, heart rate, left ventricular filling pressure, mean pulmonary artery pressure and right ventricular function indices. Both patients and parameters were projected on the most meaningful factorial plane generated by correspondence analysis. This two-dimensional graphical representation showed that all the information was roughly distributed along the 2 orthogonal axes defining this plane. Survivors and nonsurvivors were fairly well separated along the first factorial axis (prognostic axis) which was highly correlated with both outcome and left ventricular function parameters. AMIs and IMIs were grossly separated along the second factorial axis (topographical axis) which was rather well correlated with location and right ventricular function parameters. These studies suggest that AMI and IMI hemodynamic profiles are modulated by the presence or absence of right ventricular dysfunction. Moreover right ventricular dysfunction may be held responsible of some lack of information about left ventricular function status.

Acute Disease↗
PubMed1978

Acute mitral valve obstruction during infective endocarditis.

Five patients were found during surgery or at necropsy to have the mitral valve orifice obstructed by vegetations. They had had unexplained severe and recurrent episodes of acute febrile pulmonary oedema, and four had few cardiac ausculatory findings. Three patients died suddenly and unexpectedly; the other two were operated on and survived. In view of its ominous prognosis, acute mitral valve obstruction should be considered in patients whose pulmonary symptoms are compatible with endocarditis and are not adequately explained by the findings on examination of the heart. The condition, which should be confirmed by echocardiography, requires emergency surgery.

Adolescent↗
PubMed1978

[Comparison of hemodynamic and coronary effects of 2 antianginal vasodilator drugs: nifedipine and trinitrine].

Twenty patients with coronary insufficiency had measurements taken while they were in normal rhythm (NR) and during atrial pacemaking (AP) before and after taking nifedipine (n: 12) or after intravenous perfusion of trinitrin (n: 8): measurements were taken of pulmonary capillary pressure (PCP), arterial femoral pressure (AFP), cardiac output (QC) and coronary sinus flow (QCS), coronary arterio-venous oxygen difference (DaVO2), myocardial oxygen consumption (MVO2) and the myocardial coefficient of extraction of lactates (K).--Under nifedipine in NR and AP, AFP was decreased and QC increased. QSC was increased in NR, but was not changed under AP. DaVO2 was shortened under both sets of conditions. MVO2 decreased only during AP. Nifedipine brought back to normal the lowering of K which occurred with pacemaking.--Under trinitrin, both in NR and under AP, AFP, PCP, QC, QSC and MVO2 were lowered. K and DaVO2 were unchanged.--A plethysmographic study in 13 patients showed that these haemodynamic effects could be explained by the arterial vasodilator action of nifedipine which occurred without changing the venous tone, and the mixed action of trinitrin.

Adult↗
PubMed1978

[Pulmonary arterial hypertension caused by neoplastic thrombosis of the pulmonary artery].

Neoplastic thrombosis of the pulmonary artery is a rare and little known cause of pulmonary arterial hypertension. The clinical picture is one of acute respiratory failure and progressive right ventricular failure caused by pre-capillary pulmonary hypertension. In the living patient there is no way of distinguishing this condition from that of subacute cor pulmonale due to embolism, especially as the primary tumour is not always found either because it is too small or because it has already regressed by the time it has metastasised. The diagnosis usually rests on histological examination of the lungs, and two pathological types can be distinguished: carcinomatous lymphangitis with secondary invasion and thrombosis of the pulmonary arterioles on the one hand, and the neoplastic arterial emboli of a chorio-epithelioma on the other.

Adult↗
PubMed1977

[Emergency treatment of mechanical complications of acute myocardial infarction. Septum perforations and mitral insufficiency].

Over the last three years, thanks on the one hand to improvements in surgical techniques and ressuscitation, and on the other to assisted circulation using the intra-aortic balloon, which allows improved preoperative preparation of the patients, urgent medicosurgical treatment of the mechanical complications of infarction has improved the prognosis by comparison with the recent past. During the above period, our figures for operative intervention during the first two weeks after an acute infarction have been as follows: 1. Twenty nine cases of septal perforation (17 of which had previously had assisted circulation by balloon): there were 8 immediate deaths and 8 successful cases (no secondary deaths over a follow-up period of from 2 to 41 months). In all these cases, the surgeon approached the perforation by way of the left ventricle. No patient required an additional bypass procedure. Where indicated, assisted circulation by means of a balloon should not be continued for more than a few days. If there is no improvement with its use, it seems unreasonable to proceed to surgery regardless. 2. Ten cases of acute mitral incompetence; 8 were due to ruptured papillary muscle and two to mal function. 5 patients out of the 10 had required circulatory assistance by balloon preoperatively. There were 2 immediate deaths and 8 successful cases, with one secondary death (follow-up period of between 2 and 37 months).

Acute Disease↗