GABA binding processes in rat brain and liver.

Although these studies have provided some further insight into GABA binding processes associated with transport and receptor-activation, such attempts remain limited due to the lack of specificity of the ligands used to displace these components. Thus, BMI appeared to interact with both transport and synaptic receptor sites for GABA. Perhaps certain GABA-agonists (e.g., muscimol, isoguvacine) will be shown to interact more specifically with synaptic GABA-receptors? So-called "specific" binding of GABA and its analogues, or antagonists might not be the issue to be kept in focus in this type of experiment, especially since it cannot be separated into presynaptic, postsynaptic and non-synaptic components. The specificity of an interaction of ligand with membrane site may be determined by other requirements of the particular system concerned. In any case, it seems essential to examine the binding sites, themselves, in order to define more clearly which of these are involved in receptor-activation and in uptake. An approach involving the isolation and purification of GABA-receptors should provide evidence for specific binding of GABA to its postsynaptic receptors.

[False subaortic aneurysm after surgery of calcified aortic stenosis. Apropos of a case treated successfully]. / Faux anévrysme sous-aortique après chirurgie d'un rétrécissement aortique calcifié.

The authors report a case of false aneurysm of the posterior subaortic region of the left ventricle after a technically difficult surgical decalcification in a case of aortic stenosis. At reoperation, the surgeon used the femoral artery and both vena cavae for canulation. A direct approach of this "vascular" tumour, which was exterior to the great vessels, confirmed the diagnosis and enabled the localisation of the internal orifice inside the left ventricle. This was closed simply by suturing. No previous cases of this kind were found in the literature. This report underlines the necessity of taking the greatest care when decalcifying this region in order to avoid this type of serious complication.

[Perioperative ischemia in coronary surgery caused by coronary spasm of an angiographically normal coronary artery]. / Ischémie périopératoire en chirurgie coronaire par spasme coronaire sur artère radiologiquement normale.

Spasm of healthy native coronary arteries is rare but a serious cause of perioperative ischaemia after coronary bypass surgery. The authors report five characteristic cases. In each case, the spasm presented with giant ST elevation and haemodynamic changes. In one case, further coronary bypass surgery was required. In three cases, symptomatic treatment of the hypotension associated with diltiazem completely cured the problem. One case was complicated by a small myocardial infarction. There were no fatalities. Previously reported cases often describe very heavy therapeutic protocols, justified by the high risks of this condition. Due to the fact that it is not possible to identify a target-population, simple prophylactic treatment with diltiazem seems to be justified in patients undergoing coronary artery bypass surgery.

[Results of cardiac surgery in patients over 70 years of age. Apropos of a retrospective study of 170 patients]. / Résultats de la chirurgie cardiaque chez les patients âgés de plus de 70 ans. A propos d'une étude rétrospective concernant 170 patients.

The ever increasing age of the general population and the frequency of coronary and aortic lesions in patients aged 70 or older make cardiac surgery in the elderly a topic of current interest. In a retrospective study of 170 cases the overall mortality rate was 14 p. 100 (4.7 p. 100 in 1986). During the past two years (1985 and 1986), the mortality rates in patients with coronary disease who underwent elective surgery were 10 p. 100 and 4 p. 100 respectively. Emergency surgery (left coronary trunk and unstable angina excluded) and associated operations on the heart made the prognosis worse with overall mortality rates of 13 p. 100 and 15 p. 100 respectively (9 p. 100 in 1985, 10 p. 100 in 1986). In aortic valve surgery, hospital mortality rates were 28 p. 100 in 1985 and 6 p. 100 in 1986. Post-operative morbidity was high (52 p. 100 of patients) and consisted mostly of respiratory and neurological complications (14.7 p. 100 and 9.4 p. 100 respectively of all patients). Only 4 p. 100 of the patients developed peri-operative myocardial infarction. Functional results were satisfactory in both coronary disease and heart valve disease patients. The survival rate at 4 years was 74.5 +/- 10 p. 100 globally and 87.3 +/- 9 p. 100 in coronary patients operated upon electively. Thus, the considerable advances in surgical techniques and post-operative intensive care achieved during the last few years have significantly improved the results obtained in this population.(ABSTRACT TRUNCATED AT 250 WORDS)

[Evolution of the ST segment in myocardial reperfusion]. / Evolution du segment ST au cours de la reperfusion myocardique.

Intracoronary thrombolysis showed the chronological order of clinical electric and biological changes following the reestablishment of coronary flow. These changes make up the reperfusion syndrome; ST segment changes are part of this syndrome. They occur in practically all cases at the moment of reperfusion. The ST elevation may regress more or less rapidly or, on the contrary, increase transiently to a greater or lesser degree. When associated with other criteria of reperfusion-enzyme changes, arrhythmias, ST changes contribute to the indirect diagnosis of reestablishment of coronary flow. Rapid decrease in ST segment elevation is usually associated with a good myocardial outcome. The prognostic significance of transient increases in ST elevation--so called "reperfusion ischaemia"--is not fully understood, in particular its relationship to myocardial reperfusion injury. The myocardial prognosis after reperfusion may be the "biological" sum of cellular lesions due to ischaemia and reperfusion.

[Septal rupture repaired in the acute stage of myocardial infarction. Clinical, hemodynamic and angio-coronarography findings in the evaluation of surgical risk]. / Ruptures septales opérées à la phase aiguë de l'infarctus du myocarde. Evaluation du risque opératoire par les données cliniques, hémodynamiques et angio-coronarographiques.

Between 1977 and 1987, 27 consecutive patients (16 men, 11 women, mean age 66 years, range 54 to 75 years) with ventricular septal rupture complicating acute myocardial infarction underwent surgical repair. The purpose of this retrospective study was to analyse the post-operative mortality factors from clinical, haemodynamic and operative data in all patients and also from coronary angiographic data in 23/27 patients whose haemodynamic status allowed this type of exploration. Seventeen patients (63 p. 100) died during the first post-operative month, 10 survived and were discharged. Factors that influenced the prognosis were: (1) inferiorly-located necrosis associated with a 75 p. 100 mortality rate (9 out of 12 patients), as opposed to 53 p. 100 (8 out of 15 patients) with anterior necrosis; (2) right ventricular dysfunction, observed in 83 p. 100 of patients with inferior necrosis and 53 p. 100 with anterior necrosis, which was responsible for 7 out of 9 deaths in the inferior necrosis subgroup and contributed to 3 out of 8 deaths in the anterior necrosis subgroup; this established a cause-effect relationship between right ventricular function and the overmortality of patients with inferior necrosis; (3) independently of the haemodynamic status, two- and three-vessel lesions (56 p. 100 of all lesions) which had an 84 p. 100 mortality rate as opposed to 40 p. 100 with one-vessel lesions; (4) the presence of a state of shock which was associated with a 78 p. 100 mortality rate as opposed to 55 p. 100 in patients without shock. We conclude that when permitted by the patient's haemodynamic status coronary angiography should be part of the pre-operative evaluation to assess the operative risk and guide the surgical procedure.

[Cardiac hydatidosis. Review of recent literature and report of 15 cases]. / L'hydatidose cardiaque. Revue de la littérature récente à propos d'une expérience de quinze cas.

In the context of a personal series of fifteen cases of hydatid cyst of the heart, the authors present a computerized review of the last one hundred cases published in the literature. The modern features of the disease are discussed together with its severity (mortality of 23.47% in 98 recent cases). Despite the considerable contribution of ultrasonography, computed tomography and magnetic resonance imaging, a certain number of pejorative criteria appear to persist:delayed diagnosis, diagnostic error, acute pulmonary oedema and incomplete surgical cure.

[Disobstruction of the inferior vena cava under extracorporeal circulation]. / Désobstruction cave inférieure sous circulation extra-corporelle.

An original technique used to remove obstructions of the inferior vena cava under cardiopulmonary bypass is described. This technique is indicated in pulmonary embolectomy or to dispose of a vena cava clot prolapsed into the right cardiac cavities. Through a rigid and blunt thoracic drain introduced via the right atrium, a Fogarthy venous catheter is pushed into the inferior vena cava, thus avoiding the risks of accidental passage into the supra-hepatic or renal veins and blockage in a thebesian valve. The catheter is inflated, then removed together with the drain, thereby freeing the caval lumen. The technique is reliable and reproducible, and it has proved very effective.

[Peculiar indications and results of the use of a blood cell saver apparatus in cardiac surgery]. / Indications particulières et résultats de l'apport d'un appareil récupérateur de sang (ARS) en chirurgie cardiaque.

Results are reported of the use of autotransfusion by means of the blood cell saver in a group of patients at high risk for hemorrhage in Heart Surgery Department. Methods employed are described, and results are discussed: these were encouraging both from the clinical and biological viewpoints. The cost benefits of this procedure are emphasized and technical perspectives outlined with respect to recovery of plasma and platelets.

Effect of hydrocortisone and thyroxine on ATPase activities of neuronal and glial cell lines in culture.

The effect of hydrocortisone and thyroxine, on the activities of Ca2+- and Mg2+- ATPase was studied in cultured neuronal (clone M1) and glial (clones NN and C6) cell lines. For M1 and NN cells an increase in Ca2+- and Mg2+-ecto-ATPase activity was found when the cells were cultured during 4-6 days in presence of hydrocortisone or together with thyroxine. In the same conditions, a decrease in Ca2+- and Mg2+-ecto-ATPase activity was found for the C6 cells. In C6 cells the effect of hormones was more pronounced for the Mg2+- than for the Ca2+-ecto-ATPase activity. The observed decrease may be related to the tumoral origin of the C6 cells. The activity of (Na+, K+)-ATPase in all three cell lines increased in presence of hydrocortisone or together with thyroxine when the cells were cultured during 4-6 days, in presence of the hormones, whereas the total Mg2+- ATPase activity increased only after 6 days of treatment. Thyroxine alone has very few effect either on Ca2+- and Mg2+-ecto-ATPase, or on (Na+, K+)- and total Mg2+-ATPase activity. These observations are interpreted to indicate that hormones may modulate or induce enzymatic activities involved in active transport phenomena in nervous tissue.

Isolation of Enterobacter amnigenus from a heart transplant recipient.

The isolation of Enterobacter amnigenus from a human source is reported. This microorganism was grown from an intravenous catheter and, along with Pseudomonas aeruginosa, from the blood of a heart transplant patient. The biochemical characteristics and antimicrobial susceptibilities of the isolate are described.

Comparison of high-affinity binding of [3H]GABA to subcellular particles of rat brain and liver.

The binding of [3H]GABA and retention of [14C]sucrose have been studied in freshly prepared "synaptosomal-mitochondrial" (P2) fractions of rat cerebral cortex and liver using bicarbonate-buffered medium (containing 147 mEq/liter of Na+), and in frozen/thawed crude membrane fractions of rat whole brain and liver using Na+-free Tris HCl medium. GABA-sensitive sites (GSS) and bicuculline-methiodide- (BMI-) sensitive sites (BMI-SS) were defined as those amounts of [3H]GABA that were sensitive to the displacement by 10(-3) M unlabeled GABA or BMI. In the presence of added Na+, two high-affinity GABA-binding processes were detected in the P2 fraction of cerebral cortex. The lower-affinity process (likely related mainly to uptake sites) had KB approximately equal to 10(-5) M, Bmax for GSS approximately equal to 3 nmol/mg protein, and Bmax for BMI-SS approximately equal to 0.5 nmol/mg protein, whereas the higher-affinity process (likely related to synaptic GABA receptors) had KB approximately equal to 10(-7) M, BMAX for GSS approximately equal to 43 pmol/mg protein, and BMAX for BMI-SS approximately equal to 2 pmol/mg proteins. Only the higher-affinity process was detected in the liver P2 fraction, and it had KB approximately equal to 3.7 x 10(-8) M, BMAX for GSS approximately equal to 0.48 pmol/mg protein, and BMAX for BMI-SS approximately equal to 0.1 pmol/mg protein (i.e., about 1/100 and 1/20 the receptive BMAX values of cerebral cortex). This binding process of the liver P2 fraction could represent sites involved in mitochondrial GABA transport. In Na+-free Tris HCl medium, high-affinity [3H]GABA binding appeared to exist in frozen/thawed membrane preparations of both brain and liver when data were expressed on a protein basis. However, this binding to liver membranes was not displaceable by 10(-5) M unlabeled GABA, and when these data were expressed on a weight basis and corrected for [3H]GABA present in trapped supernatant fluid of the pellets, no [3H]GABA binding was detected in the liver preparation.

Modifications of platelet shape change and ATP release during cardiopulmonary bypass.

Platelet activation is accompanied by characteristic morphological changes: smooth-disc platelets become more spherical in shape and develop psudopods. The purpose of this study is to investigate whether platelets change after extracorporeal bypass. Twenty-two patients undergoing cardiopulmonary bypass (CPB) were studied prior to anesthesia and immediately after the operation. Platelets activated by different agonists were monitored simultaneously for morphological changes, ATP release and aggregation. While shape change measured before surgery was large, it was significantly reduced after bypass surgery (p < 0.01); morphological changes were quicker postoperatively. Several other parameters also changed: the time lapse between administration of the agonist and the start of ATP secretion decrease significantly (p < 0.01). After activation with high concentrations of ADP, ATP release was significantly increased (p < 0.01). On the other hand, less ATP was released after platelet activation with collagen and arachidonic acid, suggesting a change in platelet adhesion or a downregulation of endoperoxide synthesis. In our study, the importance of preactivation change in shape, estimated quantitatively by percent loss in ability of changing shape, can be compared using various agonists, with proportional defects in release and aggregation. These data provide evidence for different intrinsic levels in platelet defects after CPB.

Should we avoid ostial implantations of Wiktor stents?

Complications arising during stent implantations in coronary arteries have been reduced by technological progress and the accumulated experience of interventional cardiologists. Retrospective and prospective randomized studies with several types of stents are currently available and show improved short and mid-term results. Wiktor stent provides increased flexibility for ease of implantation particularly in curved lesions. However, the flexibility of the Wiktor stent is also associated with low resistance in the longitudinal axis. We report four cases (in 4 out of 6 ostial lesions treated and 4 out of 43 Wiktor stents implanted during a 9-month period) in which stents have become unraveled during procedures on ostial lesions (2 saphenous venous grafts and 2 native coronary arteries). Death occurred in one case and one patient was treated by emergency coronary bypass surgery. In three cases the distal extremity of the guiding catheter stretched the stent meshes during the final control angiograms, and in one case the stent was stretched during withdrawal of the deflated balloon into the guiding catheter. We believe that it is preferable to avoid using this stent in ostial lesions.