Effect of preoperative renin-angiotensin system blockade on hypertension following coronary surgery.

Renin-angiotensin system activation is suspected of being involved in postcoronary surgery hypertension, but appears to be useful in maintaining blood pressure during anesthesia and cardiopulmonary bypass. To clarify these points, 19 patients were compared: ten as a control group and nine who received captopril during two days before surgery. Anesthesia was the same for the two groups, and cardiopulmonary bypass ensured nonpulsatile flow rates. Anesthesia induced a slight decrease in the mean arterial blood pressure of the treated group (91.1 +/- 3.3 mm Hg to 83.3 +/- 3.9 mm Hg), which did not occur in the control group (89.9 +/- 5.8 mm Hg to 89.7 +/- 4.9 mm Hg). During cardiopulmonary bypass, the mean arterial blood pressure was maintained at comparable levels in the two groups (65.6 +/- 3.5 mm Hg in the control group, 72.6 +/- 3.0 mm Hg in the treated group), with same pump flow rates. After cardiopulmonary bypass, the mean arterial blood pressure returned nearly to prebypass values. Postoperatively, three patients in the control group and four in the treated group developed hypertension. Thus, preoperative renin-angiotensin system blockade by a converting-enzyme inhibitor did not impair blood pressure regulation during anesthesia and cardiopulmonary bypass, but failed to prevent hypertension following coronary surgery.

Control of HILDA/LIF gene expression in activated human monocytes.

In the present study we have investigated some of the mechanisms involved in HILDA/LIF gene expression in activated human monocytes and compared them to those of G-CSF gene expression, another monocyte-derived cytokine. In the absence of added stimuli, HILDA/LIF mRNA was barely detectable in monocytes. HILDA/LIF mRNA accumulation was weakly induced by stimuli such as LPS or phorbol ester alone, and in a synergistic manner when they were used in combination with 1,25-dihydroxyvitamin D3. Nuclear run-on transcription analysis in U937 cells did not detect an increase of HILDA/LIF gene transcription upon phorbol ester and 1,25-dihydroxyvitamin D3 stimulation. Posttranscriptional control of HILDLA/LIF mRNA levels by an increase in mRNA half-life was demonstrated in the synergy between phorbol ester and 1,25-dihydroxyvitamin D3 and in the superinduction of HILDA/LIF transcript accumulation when CHX was added to stimulated cells shortly before cell harvesting. HILDA/LIF mRNA expression was largely inhibited when U937 cells were treated with CHX either at the onset or 4 h after the beginning of the stimulation period. When CHX was added 2 h before cell harvesting, a superinduction of mRNA accumulation was obtained. G-CSF mRNA accumulation showed a different pattern of response to the same stimuli, in particular a higher rate of response to LPS. In contrast to HILDA/LIF, an augmentation of G-CSF gene transcription was detected in activated monocytic cells when compared to controls. These studies indicate that HILDA/LIF gene expression by phorbol ester- and 1,25-dihydroxyvitamin D3-treated human monocytes has a relatively specific regulation, as compared to G-CSF gene expression, and that it is largely dependent on posttranscriptional mechanisms probably acting through labile, newly synthesized proteins.

[Complement activation in extracorporeal circulation. Comparison of nylon versus polyester bubble oxygenators]. / Activation du complément au cours de la circulation extracorporelle. Comparaison d'oxygénateurs à bulles "nylon" versus "polyester".

Complement activation during cardiopulmonary bypass is well known and may influence postoperative morbidity. As nylon can particularly induce complement activation, its influence was assessed by measuring total haemolytic complement and B, C3 and C4 factors, during cardiopulmonary bypass with bubble oxygenators for coronary surgery, comparing "nylon" circuits (20 patients, Bentley BOS 10) versus "polyester" circuits (19 patients, Shiley S 100 A). Complement activation began with induction of anaesthesia and surgical procedures, B, C3 and C4 levels falling significantly (respectively 15, 17 and 20% from baseline values). The alternative pathway was activated before the classical pathway. Complement activation continued during cardiopulmonary bypass, with no more consumption of complement factors (slight variations of about 0 to 3% of the levels found after anaesthetic induction and surgical procedures). No statistically significant difference appeared between the two groups. This suggested that nylon did not significantly increase complement activation during cardiopulmonary bypass. The bubble oxygenator material cannot therefore be considered as a criterion for choosing the type of equipment.

[Bleeding after extracorporeal circulation and epsilon-aminocaproic acid]. / Saignement après circulation extracorporelle et acide epsilon amino-caproïque.

In order to assess the efficacy of epsilon aminocaproic acid in reducing bleeding after extracorporeal circulation for aorto-coronary bypass grafting, a double blind study was carried out in 57 patients. The efficiency of epsilon aminocaproic acid was assessed by the fibrinolytic activity as measured by a Von Kaulla test one hour after injection of protamine, by the amount of blood transfusions required and by the measurement of blood losses between the end of the injection of protamine and transfer of the patient to the intensive care unit, and then during the first 24 h following operation. No significant difference (p less than 0.05) between the group of treated patients and the group with placebo could be found concerning the postoperative bleeding, the amount of blood transfusions necessary and the occurrence of fibrinolysis. It was therefore concluded that there was no reason to routinely use epsilon aminocaproic acid after aorto-coronary bypass grafting.

[Automation in hematologic cytology]. / Les méthodes automatiques en cytologie hématologique.

Automation in hematological cytology can identify blood cells in suspension by new parameters: electrical field variations, light intensity modifications absorbtion or diffraction by one or two lasers, fluorescence intensity, cytochemical reactions or specific lysis. The new technology change the strategy of hematological laboratories. Automation realizes perfectly the white blood cell differential and modifies hematological language with respect to anemia and white blood cells diseases.

Regulation of HILDA/LIF gene expression in activated human monocytic cells.

We have previously shown that human monocytes express HILDA/LIF gene and its protein product upon stimulation. In the present study we have investigated some of the possible mechanisms involved in the regulation of HILDA/LIF gene expression in activated human monocytes and compared them to those of granulocyte colony-stimulating factor (G-CSF) and IL-1 beta gene expression. In the absence of added stimuli HILDA/LIF mRNA was barely detectable in isolated monocytes. HILDA/LIF mRNA accumulation was weakly induced by stimuli such as LPS or phorbol ester. However, a synergy was observed when each stimulus was used in combination with 1,25-dihydroxyvitamin D3. Nuclear run-on analysis did not detect an increase in HILDA/LIF gene transcription upon stimulation with LPS or phorbol ester in combination with 1,25-dihydroxyvitamin D3. HILDA/LIF mRNA half-life showed an increase when phorbol ester and 1,25-dihydroxyvitamin D3 were used in combination over that obtained for each stimuli alone. HILDA/LIF mRNA expression was largely inhibited when monocytes were stimulated in the presence of cycloheximide (CHX) added either at the onset or 4 h after the beginning of the stimulation period. When CHX was added at later time points, 2 h before cell harvesting, HILDA/LIF mRNA levels were superinduced when compared with those in cells stimulated in the absence of CHX. This superinduction can be at least partially explained by post-transcriptional mechanisms, since HILDA/LIF mRNA half-life in CHX-superinduced cells was significantly increased when compared with values on stimulated CHX-untreated cells. In contrast to HILDA/LIF, G-CSF and IL-1 beta mRNA accumulation showed a different response pattern to the same stimuli, and a augmentation of their gene transcription was detected by the run-on technique in activated monocytic cells when compared with controls. Furthermore, G-CSF and Il-1 beta mRNA levels were superinduced in monocytes stimulated in the presence of CHX from the onset of the stimulation period. These studies indicate that, when compared to G-CSF and IL-1 beta, the expression of HILDA/LIF gene is under the control of relatively specific regulatory mechanisms. HILDA/LIF gene expression is controlled by newly synthesized proteins acting at early and late time points of the stimulation period and with opposite effects on HILDA/LIF mRNA levels. Finally, HILDA/LIF mRNA levels are regulated by post-transcriptional mechanisms of mRNA stabilization probably controlled through labile newly synthesized proteins.

[Use of dopamine in acute cardiovascular distress. Its place in comparison to isoproterenol]. / Utilisation de la dopamine dans les états de détresses cardio-circulatoires aiguës sa place par rapport a l'isoprotérénol

Nineteen patients presenting cardiovascular distress were treated with dopamine. For seventeen of these, the accident occurred immediately after cardiac surgery. Dosages varied from 1 to 15 mug/kg/min and the duration of treatment from 10 minutes to three days. The efficacy of the treatment was judged according to the clinical and hemodynamic improvement of the cardio-circulatory function and the increase in urinary output. There were 15 favourable results. The positive effects of the dopamine seem to be limited in certain patients by the appearance of a cyanosis testifying to a rise in vascular resistances which increases the left auricular pressure and limits the inotropic effect. In these cases, isoproterenol or a combination of both isoproterenol and dopamine gives better results.

Diverse biological parameters in clinically healthy sheep from a flock with scrapie: variations, and correlations with OLA antigens.

A comparison was made in the blood levels of various cell types and biochemical substances and in lymphocyte antigens between 107 healthy sheep from a flock contaminated with scrapie (HC sheep) and 93 sheep from a noncontaminated flock (NC sheep), which served as a control population. Significant differences between the two groups of sheep were found in some of the levels, as had previously been found with lymphocyte antigens. The HC sheep, which included genetically resistant animals, could be distinguished from the NC sheep by their lower levels of various white cells, a noticeable decrease in urea, a moderate decrease in Mg2+ and Mn2+ ions, beta- and gamma-globulins, serotonin and vitamin B12, a strong increase in uric acid and a moderate increase in K+, Cl-, HCO3-, Zn2+, and Al3+ ions, as well as in total lipids and in the albumin to globulin ratio. In this HC population, the only enzyme with an increased level was aldolase; the levels of the other 7 enzymes measured were lowered. The observed modifications were considered to be signs of latent disturbances in the leukocyte system and in hepatic and renal functions, in spite of apparent resistance. Eleven lymphocyte antigens were studied. These antigens are not independent of the blood levels of the various substances measured, but are often correlated in a statistically significant manner with some of them. In the HC sheep, the lymphocyte antigens correlated with the modified levels in the blood were different from those in the control population.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of angiotensin converting enzyme inhibition on blood pressure and renal function during open heart surgery.

Activation of the renin-angiotensin system during open heart surgery may have consequences both beneficial in sustaining blood pressure and deleterious in compromising renal hemodynamics. The influence of short-term pretreatment with captopril on blood pressure and renal function was assessed double-blind versus placebo in 18 patients without pre-existing cardiac or renal failure, and undergoing coronary artery bypass. No difference in blood pressure and fluid requirement during the surgical period was observed between groups receiving captopril or placebo. Effective renal plasma flow and glomerular filtration rate decreased in the placebo group whereas they remained unaltered in the captopril group; during cardiopulmonary bypass, urinary excretion of sodium was greater in patients receiving captopril than those receiving placebo. These results suggest that captopril pretreatment does not compromise the control of blood pressure and renal function during open heart surgery; additional studies on the protective value of angiotensin-converting enzyme inhibitors are warranted in patients at higher risk for developing renal failure.

Hemodynamic effect of calcium channel blockade during anesthesia for coronary artery surgery.

Because the choice of anesthetic technique does not influence the incidence of perioperative myocardial ischemia, reduction of ischemic risk may require specific antianginal therapy. Calcium entry blockers are effective drugs in antianginal therapy. Diltiazem reduces myocardial oxygen demand through decreases in heart rate, inotropy, and systolic function, while increasing myocardial oxygen delivery through coronary vasodilation. These potentially beneficial effects of diltiazem were evaluated in 15 of 29 patients (diltiazem v placebo, double-blind study) scheduled for coronary artery bypass graft surgery. Continuous infusion of diltiazem (0.15 mg/kg bolus followed by 2 micrograms/kg/min), during anesthesia and surgery before cardiopulmonary bypass, significantly reduced the major MVO2 determinants during anesthesia with moderate doses of fentanyl and a benzodiazepine (midazolam in 8 of 14 control patients and 9 of 15 treated patients, or flunitrazepam in the others). Heart rate, mean arterial pressure, and inotropy were decreased during the most stressful events of surgery when plasma diltiazem concentrations were in the therapeutic range (greater than 96 ng/mL). The number of patients with perioperative ischemia was 2 of 15 in the treated group and 4 of 14 in the control group. Provided that diltiazem plasma concentrations are sufficient, it can contribute to lowering the ischemic burden during anesthesia for coronary artery surgery.

Myocardial depressant effect of nitrous oxide after coronary artery bypass graft surgery.

We have studied the cardiovascular effects of nitrous oxide after cardiac ischaemia-reperfusion injury caused by aortic cross-clamping and unclamping during coronary artery bypass grafting (CABG). At the time of chest closure, 20 patients were allocated randomly to receive oxygen and air (FIO2 = 0.5) or 50% nitrous oxide in oxygen in addition to anaesthesia with fentanyl. Nitrous oxide significantly decreased mean arterial pressure (P less than 0.01) and cardiac index (P less than 0.05), which suggests that nitrous oxide with fentanyl may significantly depress left ventricular performance after CABG. Although ischaemia-reperfusion cardiac injury did not appear to increase the myocardial depressant effect of nitrous oxide, the use of nitrous oxide is not recommended immediately after CABG.

[Comparison of two E.E.C. baths by study of the oncotic pressure-pulmonary artery pressure gradient]. / Comparaison de deux bains de C.E. C. par l'étude du gradient pression oncotique-pression artérielle pulmonaire.

Variations in oncotic pressure-pulmonary artery diastolic pressure gradient and in intrapulmonary shunt were studied in two groups of patients undergoing surgery with extracorporeal circulation for aortocoronary bypass of excision of an aneurysm. The two groups, differed only in terms of the E.C.C. bath (Group A: Ringer Lactate; Group B: DDextran 60,000). The effects of E.C.C. on these parameters were as follows: - decrease in both groups in the gradient (OP-PAP) (respectively P < 0.001 and P < 0.01) but with a more marked decrease in group A than in group B (P < 0.05) with non-negativisation of the gradient in that group; - non-significant variations in Qs/Qt in both groups without any correlation with gradient (OP-PAP). The onset of pulmonary oedema associated with a decrease in gradient (OP-PAP) leads to the suggestion of the use of Dextrans in pathological situations where OP is low or PAP high and all the more so when both of these factors are present.

[Anesthesia in reoperations in abdominal surgery]. / L'anesthésie dans les réinterventions en chirurgie abdominale

Fifty one patients from different surgical units, hence anesthetized by different anaesthesists, underwent reinterventions in abdominal surgery. The indications for the first intervention essentially involved the supra-mesocolic region of the abdomen (62 out of 100 cases). The operative risk during the first intervention was on the average 18 pour cent. The protocol of the first anaesthesia which was known in 42 cases, was of the narco-ataralgestic type. The date of the return to the operation table varied from 1 to 60 days. The state of the patients was in general catastrophic (organic renal failure, acute respiratory failure). Here again the anaesthesia was of the narco-ataralgesic type but the choice of drugs varied depending on the patients' state. However non significant difference was noted in the average hourly drug consumption between the two interventions. Apart from one circulatory arrest during induction, in one patient with hemorrhagic shock, no death was attributable to the anesthetic technique. The authors, using these findings, attempt to pick out a practical line of behaviour.