Which functional processes control the short-term effect of grazing on net primary production in grasslands?

Grazing has traditionally been viewed as detrimental to plant growth, but it has been proposed that under certain conditions, grazing may lead to compensatory or overcompensatory growth. However, comprehensive information on the relative role of the main functional processes controlling the response of net primary production (NPP) to grazing is still lacking. In this study, a modelling approach was used to quantify the relative importance of key functional processes in the response of annual canopy NPP to grazing for a West African humid grassland.

[Percutaneous closure of patent ductus arteriosus: results and costs compared to surgical closure].

The comparison of the clinical results and costs of the two methods of closure of patient ductus arteriosus was undertaken in two comparable groups of 40 patients treated in the same period in the same hospital. After transcatheter closure there was a 9% residual shunt rate at 3 years, the 2 patients with a residual continuous murmur being operated secondarily. The only complication was severe haemolysis which regressed after transcatheter ablation of the prosthesis.

[Double-chamber right ventricle, aortic subvalvular stenosis and interventricular septal defect. Apropos of 12 cases].

The authors report 12 cases of double-chamber right ventricle associated with discrete subaortic stenosis and ventricle septal defect. The statistics derived from 3,292 surgical reports of congenital heart diseases operated on at the Marie-Lannelongue Surgical Center over an 8 years period show that this association is 7 times more frequent than the law of chance. Twenty-two per cent of double-chamber right ventricles had an associated discrete subaortic stenosis and, in 9% of cases of subaortic stenosis a double-chamber right ventricle was observed.

[Percutaneous mitral valvulotomy: comparison of 2 techniques in 100 matched-pair patients].

The results of percutaneous mitral valvulotomy by the Double Balloon and the Inoue Balloon were compared in 100 patients referred to Marie-Lannelongue Hospital between 7/11/86 and 8/3/91, paired for age, sex and echocardiographic features of the mitral valve. The transvalvular diastolic pressure gradient at catheterisation or Doppler echocardiography decreased significantly and similarly with the two techniques: -65 +/- 19% versus -64 +/- 15% (p = 0.10) and -66 +/- 22% versus -58 +/- 23% (p = 0.

[Lung resection for cancer in coronary patients. Immediate and medium-term results. Retrospective study in a series of 51 patients].

Patients with both resectable lung cancer and coronary artery disease require preoperative cardiac evaluation in order to determine and prevent the surgical risk and to discuss the desirability of preventive myocardial revascularization. The results of thoracic surgery in coronary disease patients have been studied in a series of 51 patients operated upon for lung cancer at the Marie Lannelongue hospital, Paris, between 1985 and 1988. Thirty-two patients underwent non invasive exploration prior to surgery (exertion ECG in 22, myocardial radioisotope scanning in 10); 35 patients had coronary arteriography at the last moment, and 9 asymptomatic patients with an old history of myocardial infarction had no specific exploration.

[Endoluminal occlusion, using a catheter, of patent ductus arteriosus in an adult].

The risk of surgical closure of the ductus arteriosus in the adult is greater than in children. The ductus arteriosus can now be occluded by venous catheterisation using a Rashkind umbrella. This procedure vas performed in a 63 year old woman.

[Coaxial catheterization with an ultra-flexible catheter (Tracker) in coronary angioplasty].

After experiencing problems of catheterisation during coronary angioplasty, the authors tried using a 3.2 F ultraflexible catheter with a 2.2 F tapered tip.

[Value of superior angiocardiography in the evaluation of the surgical excision of bronchial cancer. Respective role compared to thoracic x-ray computed tomography].

The place of angiography-superior vena cavography in the assessment of the resectability of a lung cancer must be defined in comparison with the data provided by thoracic computed tomography. Sixty-six patients with proximal lung cancers of doubtful resectability were studied by means of angiography and computed tomography and the results of these preoperative investigations were correlated with the operative findings. The sensitivity of these two examinations for the diagnosis of vascular invasion preventing pulmonary resection is poor (53% and 47% respectively).

[Treatment of rheumatic mitral stenosis in children and adolescents by a balloon catheter].

Between April 1986 and August 1987, eight children, 9 to 18 years old, with rheumatic mitral valve stenosis underwent a percutaneous balloon valvotomy. Immediate results were good. By echocardiographic measurements, mean transmitral gradients went from 23.

[Atrial septal defect and cyanosis. Apropos of 6 cases related to abnormal drainage of the inferior vena cava into the left atrium].

The authors report six cases of atrial septal defect (ASD) associated with abnormal drainage of the inferior vena cava into the left atrium responsible for right-to-left shunting, without pulmonary hypertension. The abnormal drainage could be due either to an anatomical malposition of the inferior vena cava opening into the left atrium, or to an abnormal blood flow from this vein, normally located through a low ASD, under the influence of anatomical, mechanical and haemodynamic factors. Clinically, all patients presented with light cyanosis and with the usual signs of ASD.

[Endoluminal mitral valvuloplasty in young adults and children. Apropos of 10 cases].

Between April 1 and May 15, 1986, transluminal dilatation of the mitral valve was performed at the Marie-Lannelongue Hospital, near Paris, in 10 patients aged from 12 to 48 years (mean 25,3 years) suffering from rheumatic mitral stenosis with supple valve leaflets. The procedure, carried out under local anaesthesia, included trans-septal catheterization followed by installation of one, then usually two balloons opposite the mitral orifice. The total diameter of the balloons was often greater than that of the mitral annulus.

[Percutaneous transluminal angioplasty in complex congenital cardiopathies. Apropos of 2 cases].

Percutaneous transluminal angioplasty (PTA), already widely used in stenosis of peripheral, renal or coronary arteries, has now been extended to congenital heart diseases. Thus, in pulmonary or aortic orificial stenosis this simple and fairly safe method has proved to be a suitable alternative to surgery. In other cases it may be used for tiding the patient over a critical period pending surgery.

[Rheumatic mitral stenosis. The medical solution].

The first case of balloon catheter valvular dilatation for rheumatic mitral stenosis is reported in a 13 year-old child. The technique, under local anesthesia, required a transseptal access, then the introduction of one, then simultaneously 2 balloon catheters through the mitral valve. A perfect opening of the valve, without mitral insufficiency was obtained.

[Non-surgical treatment of pulmonary valve stenosis].

Percutaneous pulmonary valve valvuloplasty was attempted 17 times in 16 infants and children aged 15 days to 18 years. Valvuloplasty was performed during cardiac catheterization without general anesthesia. Balloon catheter was positioned across the pulmonary valve using a guide wire previously introduced in the right or left pulmonary artery.

[Adult pulmonary valvular stenosis, major stenosing right ventricular hypertrophy and tricuspid insufficiency. Apropos of 2 cases].

2 cases of severe pulmonary valvular stenosis in two young adults aged 21 and 29 years respectively are presented. Despite the degree of stenosis (4 mm jet), the right ventricular pressures did not exceed systemic pressures because of severe tricuspid regurgitation. This dominated the clinical and anatomical findings, causing aneurysmal dilatation of the right atrium and displacement of the tricuspid valve to the left.

[Malformations of the tricuspid valve associated with Fallot's tetralogy. Apropos of a series of 224 surgically treated Fallot's tetralogies].

This study was based on 7 children aged 20 months to 13 years with tetralogy of fallot (TOF) and tricuspid valve defects. Cases of endocardial cushion defects (8 cases of atrioventricular) were excluded. Three types of tricuspid valve defect were observed: 4 tricuspid valve prolapse (with one associated mitral valve prolapse); 2 accessory tricuspid valves passing through a ventricular septal defect to prolapse in diastole under the aortic valve; 1 Ebstein anomaly.

[Two-dimensional echocardiography of coronaro-cavitary fistulas].

4 cases of congenital coronary arteriovenous fistulae in children 20 days to 10 years old were studied by 2D echocardiography. The coronary fistulae were treated surgically in all four cases after biplane aortography and selective coronary arteriography. The visualisation of the coronary arteries was performed by systematic use of several echocardiographic views: - left parasternal short axis view through the aortic root, - apical view, - longitudinal and transverse subcostal views.

[Assessment of the branches of the pulmonary artery by 2-dimensional echocardiography].

Sixty three cases of Fallot's tetralogy aged from 1 month to 30 years old, were studied by 2D echocardiography to evaluate the diameter of the pulmonary arteries and to detect stenosis of the main pulmonary arteries. The right pulmonary artery was visualised clearly enough to be measured in all 63 cases whereas the left pulmonary artery could only be adequately recorded in 58/63 cases. The junction of the two pulmonary arteries was confirmed by 2D echo in 61/63 cases; in two cases, the left pulmonary artery was not connected (2/63), confirmed at angiography and surgery.

[Diagnosis of a complete atrioventricular canal with infundibular pulmonary stenosis and left superior vena cava by 2-dimensional contrast echocardiography. Apropos of a surgically treated case].

The case of an eight year old child with complete atrioventricular canal, pulmonary infundibular stenosis and persistent left superior vena cava draining into the coronary sinus is reported. Two-dimensional echocardiography with injection of contrast in a left arm vein gave a precise and complete diagnosis of the malformations before catheterisation and angiography. The complete atrioventricular canal was demonstrated by apical four-chamber views.