Metastable atomic configurations of Rh, Ir, and Pt on W(110).
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Journal Article↗
Biomedical subjects
E Bauer
Publications and source records attributed to E Bauer.
[Vascular complications associated with aortic dissection].
Aortic branch occlusion may constitute the mode of presentation or become an important focus of treatment in patients sustaining acute aortic dissection. The optimal therapeutic approach in patients with acute aortic dissection complicated by cerebral, visceral and peripheral vascular problems, and the implications of such complications, are not well established. We review the outcome in 187 consecutive patients (149 males and 38 females, mean age 58 years) with acute dissection of the thoracic aorta who were admitted and operated on in our department over a 13-year period. We assess the incidence, consequences and specific management of significant stenotic and obstructive lesions of the aorta and its branches. Noncardiac vascular complications occurred in 59 patients (32%); of these complications, 38 were associated with type A dissection (incidence 28%) and 21 with type B dissection (incidence 48%). A trend towards decreasing overall surgical mortality was observed in the second part of the study (1983-1989) compared with the first part (1977-1982) i.e. 28% versus 12%. Although aortic rupture and cardiac tamponade were the strongest correlate of morbidity and mortality, death specifically related to vascular complication was more common when such malperfusion occurred in the carotid, celio-mesenteric and renal circulation. Proximal aortic repair at the site of the intimal tear with obliteration of the false lumen may have restored adequate distal circulation in 27 patients in whom improvement of the visceral or peripheral ischemia was observed after the thoracic aortic repair. Additional procedures (immediately after the thoracic repair or later) were necessary in 15 patients to restore adequate perfusion in the compromised area.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Different interactions of platelets with arterial and venous coronary bypass vessels.
We studied the interaction of platelets with the wall of human internal mammary arteries and saphenous veins, suspended in organ chambers for measurement of isometric tension. Vessels were obtained during coronary bypass surgery and cut into 5 mm rings; in some the endothelium was chemically removed. Rings from several patients were randomly chosen for each experiment, and in each ring six concentrations of platelets (from healthy blood donors; 1-75 x 10(3)/microliters) were tested consecutively and concentration-response curves constructed; the areas under these curves were used for statistical comparisons. In rings of internal mammary artery contracted in response to noradrenaline, aggregating platelets induced endothelium-dependent relaxation which was prevented by apyrase (0.67 U/ml ADPase activity) and L-NG-monomethylarginine (1 mmol/l). By contrast, in saphenous vein rings contracted in response to noradrenaline, aggregating platelets induced only a further increase in tension. In quiescent vessels, the platelet-induced contraction did not occur in arteries with endothelium but that in veins was greater and facilitated by endothelium. Preincubation of platelets with aspirin (10 mumol/l) reduced the contraction in both vessels, but contraction was abolished only in the presence of both the thromboxane receptor antagonist SQ-30741 and the serotoninergic (5HT2) receptor antagonist ketanserin. These findings show that platelet-derived ADP causes release of nitric oxide by the endothelium of internal mammary artery but not of saphenous vein; thromboxane A2 and serotonin mediate contraction in vein but not artery with endothelium. These differences may contribute to differences in graft function and the clinical efficacy of antiplatelet drugs.
Apyrase↗
Low-dose aprotinin for reduction of blood loss after cardiopulmonary bypass.
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Aprotinin↗
Improved forceps for pulmonary embolectomy.
A malleable, nonocclusive forceps for surgical extraction of fresh pulmonary emboli is described. This device allows the performance of pulmonary embolectomy under direct vision with an unobscured peripheral field and reduces the potential for traumatic pulmonary artery laceration.
Equipment Design↗
Validation of the TNM classification (4th edn) for lung cancer: first results of a prospective study of 1086 patients with surgical treatment.
For the purpose of testing the validity of the new TNM classification (fourth edition) for lung cancer, data from 1086 patients with surgical treatment were analysed prospectively. Several items were examined: (1) the agreement between clinical (TNM) and pathologically confirmed classification (pTNM); (2) the value of the various diagnostic tests in estimating the pathologically confirmed classification; (3) the influence of the TNM definitions on separating distinct prognostic groups. With regard to the primary tumour (T), clinical and pathological classification were identical in 64% of the cases. With regard to lymph node involvement (N), the agreement was 48%, for distant metastasis 90% and for the staging 55%. As for the primary tumour (T), the accuracy of radiography (59%) was nearly identical with that of computed tomography (58%). Both these diagnostic techniques were less precise in determining the extent of lymph node involvement (computed tomography 50% correct assessments, radiography 43%). The statistically significant differences in the prognoses for the various pT, pN and pM categories as well as for the pathological stages and the categories of the new R classification could be confirmed. The new 1987 TNM definitions for lung cancer make possible international conformity; the classification is also practically useful and the prognostic relevance improved. The new classifications thus provide a more reliable basis for establishing guidelines for individual oncological therapy strategies and for the exchange of information between different centres on the progress made in diagnosis and therapy of lung cancer.
Carcinoma, Bronchogenic↗
Diagnostic and therapeutic strategy in malignant pleural mesothelioma.
We retrospectively analysed 301 patients with diffuse malignant pleural mesothelioma (235 male, 66 female; median age 59 years). Prognosis depended significantly on patient age, evidence of pain, loss of weight, tumour cell type, stage, local and distant metastasis, involvement of peritoneum and surgical treatment. The overall median survival rate was 238 days, after extended pleuropneumonectomy 284 days, and after decortication 315 days - significantly better than the prognosis in patients without surgical treatment or exploratory thoracotomy. Pleuropneumonectomy should only be considered in young patients with an epithelial cell-type tumour (possibly with adjuvant chemotherapy). Decortication seems nowadays to be the treatment of choice.
Adult↗
Dealing with dilated ascending aorta during aortic valve replacement: advantages of conservative surgical approach.
Five to fifteen percent of patients undergoing aortic valve replacement (AVR) will have an ascending aortic aneurysm requiring a concomitant surgical procedure. On the other hand, a dilated ascending aorta is known to be a potential source of complications after AVR. From 1972 to 1988, 2278 AVR, either isolated or combined with a second cardiac procedure, were performed in our institution. In the same time interval, a dilated ascending aorta was treated in additional 291 consecutive patients during AVR. Three different surgical options were employed: aortic remodelling and external wall support in 164 patients (56.4%), composite graft replacement in 81 patients (27.8%) and a supracoronary graft in 46 patients (15.8%). Early mortality was 4.8%. Aortic remodelling plus external wall support had the lowest early mortality (1.8%) and the best 8-year survival (89.6%). Supracoronary grafting had a higher early mortality (6.4%) and lower 8-year survival (73.2%). The results of the composite graft were least favourable: early mortality was 9.8% and 8-year survival 76.5%. The results point out the necessity for instituting the appropriate surgical procedure for a dilated ascending aorta during AVR. They show that conservative aortic surgery with preservation of endothelial lining gives excellent early and late results.
Actuarial Analysis↗
Many-body correlations effects in quasielastic electron scattering.
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Journal Article↗
Different activation of the endothelial L-arginine and cyclooxygenase pathway in the human internal mammary artery and saphenous vein.
The endothelium releases substances controlling vascular tone and platelet function. We investigated mediators of endothelium-dependent responses in human internal mammary arteries and saphenous veins. The inhibitor of nitric oxide formation, NG-monomethyl L-arginine, enhanced the sensitivity to norepinephrine (fivefold) and evoked more pronounced endothelium-dependent contractions in internal mammary arteries (19 +/- 6% of 100 mM KCl) than in saphenous veins (2 +/- 1%; p less than 0.005). In internal mammary arteries, NG-monomethyl L-arginine, but not indomethacin, markedly reduced endothelium-dependent relaxations to acetylcholine (from 95 +/- 2% to 39 +/- 7%; p less than 0.005) and prevented those to histamine (78 +/- 6% to 4 +/- 3%; p less than 0.005). In saphenous veins, endothelium-dependent relaxations to acetylcholine were weak (24 +/- 11%), while nitric oxide caused comparable relaxations (85 +/- 3%) as in internal mammary arteries (80 +/- 5%; NS). NG-Monomethyl L-arginine prevented the relaxations to acetylcholine and unmasked endothelium-dependent contractions (30 +/- 10%). Indomethacin and the thromboxane synthetase inhibitor CGS-13080 augmented relaxations of saphenous veins to acetylcholine from 24 +/- 11% to 46 +/- 9% (p less than 0.05). Histamine-evoked contractions were converted to endothelium-dependent relaxations by indomethacin and the thromboxane A2/endoperoxide receptor antagonist SQ-30741 (38 +/- 3% and 40 +/- 6%; p less than 0.05) but not CGS-13080. Thus, 1) nitric oxide mediates endothelium-dependent relaxations in human arteries and veins; 2) internal mammary arteries release more nitric oxide than do saphenous veins, and 3) in saphenous veins, the effects of nitric oxide are reduced by endothelium-derived contracting factors originating from the cyclooxygenase pathway.
Acetylcholine↗
Purification of a procollagenase-activator present in medium of cultured guinea pig carrageenin granuloma.
Activation of procollagenase constitutes a crucial event in collagenolytic activity regulation. In this study we have purified by DEAE-cellulose, Ultrogel AcA-44, and zinc chelate sepharose chromatographies, a procollagenase-activator from the culture medium of the guinea pig carrageenin granuloma model. On SDS-PAGE, the activator migrates as a principal band of Mr approximately 44,000. The molecule activates procollagenase from human lung fibroblasts in a concentration dependent manner and an enhancement of collagenase activity of trypsin-treated crude culture medium was observed. A loss of about 50% of its activity occurs after heating. In addition, this activator degrades gelatin and casein. All these data suggest that this procollagenase-activator might be stromelysin. The activator was found in both phases of the granuloma, at 7 days when collagen is actively deposited and an important proportion of the collagenolytic activity remains in latent form; and at 14 days, when this enzymatic activity is fully expressed.
Animals↗
Low-dose aprotinin also allows reduction of blood loss after cardiopulmonary bypass.
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Aprotinin↗
[Reduction of postoperative blood loss and donor blood use in heart surgery with aprotinin: experience with various dosages].
The effect of high dose aprotinin was evaluated in a prospective study on 100 patients undergoing cardiopulmonary bypass. Special attention was made on postoperative blood loss and transfusions of bank blood postoperatively. In the first part of the study, after induction of anesthesia, a loading dose of 2,000,000 kallikrein-inhibiting-unit (KIU) = 280 mg aprotinin was given intravenously over a 30-min period. Immediately afterward, a continuous infusion of 500,000 KIU/h was started and maintained until skin closure. Another 2,000,000 KIU was added to the priming volume of the heart-lung machine. A control group of 50 patients was randomized with similar indication for surgery and past cardiac history. The total loss from the thoracic drains was significantly reduced in the aprotinin group as compared with the loss in the control group (490 +/- 265 ml versus 1045 +/- 380 ml). In a separate group of risk patients (redo-operations, infective endocarditis) the total blood loss was even more significant reduced in the aprotinin group (690 +/- 195 ml versus 1585 +/- 290 ml). Patients of the aprotinin group received markedly less bank blood postoperatively (350 +/- 100 ml versus 900 +/- 240 ml without aprotinin). Part II of the study (36 patients) consisted of lower dosage (2,000,000 KIU intravenously during induction of anesthesia only or 2,000,000 KIU in the priming volume of the heart-lung machine only). Patients who received aprotinin in the heart-lung machine only showed no significant difference regarding blood loss and blood requirement to patients with high dose aprotinin. It appears possible that aprotinin reduces the activation of the coagulation during cardiopulmonary bypass and preserves platelet function without affecting platelet consumption during the extracorporeal circulation. The results of our study demonstrate that high dose aprotinin markedly reduces blood loss as well as homologous blood requirement in the early postoperative course of cardiosurgical patients. Similar effects due to reduced aprotinin dose have been observed in patients receiving aprotinin in the extracorporeal circulation only.
Aged↗
[Preventive cytolytic treatment following heart transplantation: ATG versus OKT3].
The postoperative prophylactic cytolytic therapy with rabbit-ATG and OKT3 after heart transplantation are compared. The first 20 recipients were treated with ATG (5 days), the next 20 with OKT3 (14 days). The medium histological rejection grade (Texas classification) was significantly higher after 2 weeks in ATG group and after 4 weeks in OKT3 group. The linearised rejection rate was 7.1 (ATG) vs. 0.7 (OKT3) (p less than 0.005) at 2 weeks, resp. 3.6 vs. 8.6 (p less than 0.05) and 1.3 vs. 2.9 (p less than 0.005) at 4 weeks and 2 months. After 3 months there was no difference in histological rejection grade (3.6 +/- 1.5 vs. 3.3 +/- 1.7) and linearised rejection rate (2.4 vs. 2.6 per 100 days and patient) between the two groups. Severe rejections are more frequent after OKT3 (6 vs. 11) and probability of rejection free survival is higher after ATG (25% vs. 0%, resp. 21% vs. 0% after 2 resp. 3 months; p less than 0.05). In this study we find no short and medium term benefit of a rejection prophylaxis with OKT3 (14 days) compared with ATG (5 days). Acute allograft rejections in OKT3 group tend to be more severe with a higher mortality.
Antibodies, Monoclonal↗
[Simultaneous coronary and vascular surgery interventions: indications,technique and results].
Atherosclerosis is often a generalized disease, affecting not only coronary circulation, but other parts of vascular system as well. Vascular diseases most commonly encountered in patients with coronary atherosclerosis are carotid disease, abdominal aortic aneurysm and obliterative atherosclerosis in aortoiliac segment. In such situation two options are available: to treat the more significant, life-threatening manifestation first and postpone the other operation--staged approach; or to perform coronary artery bypass grafting (CABG) and other vascular procedures during one single operation--synchronous surgery. The advantages of this latter approach are obvious: patient has to undergo only one operation; there is no additional risk in the waiting period for second operation; surgical treatment is greatly accelerated. From 1978 until July 1990 a total of 123 synchronous CABG and vascular procedures were carried out in our clinic. In the same period, CABG was performed in 3867 pts in the same institution; combined procedures amount to 3.5% of all coronary revascularisations performed in the same period. CABG was done together with carotid endarterectomy (CEA) in 45 pts, associated with resection of abdominal aortic aneurysm (AAA) in 31 and in 28 pts it was combined with vascular procedures in aorto-iliac or femoral segment. In 4 pts a triple procedure--CABG, CEA and peripheral vascular reconstruction--were undertaken. Thoracic aortic aneurysm and CABG were performed in 15 pts. CEA is performed immediately prior to CABG in symptomatic carotid disease, past history of transient ischemic attack, severe bilateral carotid disease and unilateral carotid obstruction with contralateral stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)
Aortic Aneurysm↗
[Simultaneous revascularization of the renal arteries in conjunction with reconstruction of aneurysms of the abdominal aorta].
Simultaneous revascularization of stenosed renal arteries during resection of aneurysms of the abdominal aorta was performed in a consecutive series of 30 patients (mean age: 65 +/- 7 years; men 27 [90%]; women 3 [10%]). Right renal artery was operated upon in 20/30 cases (66%) and left renal artery in 15/30 cases (50%) for a mean degree of stenosis of 79 +/- 19%. Suprarenal extension of the aneurysm of the abdominal aorta was observed in 7/30 cases (23%). Emergency operation because of rupture of the aneurysm was necessary in 7/30 cases (23%). The following procedures were performed upon the renal arteries, either isolated or combined, in addition to resection of the aneurysm of the abdominal aorta: reimplantation of the renal artery in 15 cases, thrombendarteriectomy of the renal artery in 11 cases, patchangioplasty in 8 cases, bypass in 4 cases, dilatation in 1 case, autotransplantation in 1 case. The 30-day mortality was 1/23 (4%) for elective procedures versus 3/7 (43%) for emergency procedures (ruptures). Systolic (diastolic) blood pressure dropped from a preoperative mean value of 181 +/- 139 (104 +/- 18) mm Hg to a postoperative mean value of 147 +/- 18 (80 +/- 18) mm Hg: p less than 0.05 (p less than 0.05). Hence, simultaneous revascularization of stenosed renal arteries during resection of aneurysms of the abdominal aorta helps not only to salvage renal parenchyma but also to control the risk factor hypertonia in a significant number of patients.
Adult↗
[Blood transfusion and reducing the need for blood in heart transplantation].
Viral infections transmitted by the donor organ or by blood and blood products are severe complications in heart transplantation. The use of blood and blood saving management is evaluated in 57 consecutive orthotopic heart transplantations. Indication was cardiomyopathy in 63%, coronary artery disease in 30%, valve disease in 5%, congenital in 5%, arrhythmia in 5% and primary cardiac malignancy in 2%. Previous open heart surgery was performed in 32%, and 81% had anticoagulation, with a mean quick value of 0.28 +/- 0.13. The total use of blood and blood products was 1151 units and was distributed as follows: whole blood and packed cells 41%, platelets 17%, fresh frozen plasma (FFP) and coagulation factors 36%, albumine 7%. Anticoagulated recipients received more FFP and factors, 7.9 +/- 5.7 U vs. 4.4 +/- 4.8 U. In the reoperation group 78% vs. 22% (p less than 0.001) in the primary operation group received platelets. Hemodilution to hematocrit 0.24 instead of 0.30 lead to a decrease of red cell transfusions per patient from 12.3 +/- 6.7 U to 6.3 +/- 7.4 U (p less than 0.001) and the percentage of patients receiving red cells was reduced from 100% to 82%. Intraoperative hemofiltration was performed in 49% (mean filtration volume was 1652 +/- 910 ml). No differences in the amount of blood and blood products could be shown. Heart transplantation is an operation with a high need for blood and blood products. Reoperation and anticoagulation are predictors for a higher use of platelets, FFP and coagulation factors. Hemodilution reduces the use of red cells, whereas intraoperative hemofiltration has no influence on the use of blood.
Adolescent↗
[Peritoneal dialysis in treatment of postoperative heart failure after correction of complex heart defects in young children and infants].
Low cardiac output can be encountered after corrective surgery for complex congenital malformation in children and infants and is often accompanied by an impairment of renal function, ascites, hyperosmolarity and hyperpyrexia. In most instances, combined afterload-reduction and inotropic stimulation will be effective. If low cardiac output persists, a peritonealdialysis (PD) may allow correction of fluid balance and consecutive improvement of hemodynamics. During a 18 month-period, PD was performed in 14 children in the postoperative period following major cardiac surgery (transposition 5, Fallot tetralogy 5, various complex anomalies 4). This represents 3.1% of all cardiac operations performed in children with congenital heart disease throughout the same period. There were 8 males and 6 females with a median age of 2.5 years (range 3 days to 4 years) and a median bodyweight of 5.5 kg (range 3.4 to 10 kg). Low cardiac output was defined when two or more of the following factors were met: mean arterial pressure (MAP) below 40 mm Hg despite inotropic stimulation, central venous pressure (CVP) over 15 mm Hg, urine production less than 1 ml/kg/hour and/or increasing transaminases. Before starting peritoneal dialysis all children received combined positive inotropic and vasodilative therapy. The PD-catheter was introduced 8 to 30 hours after operation. We used a PD-solution with 1.5% and/or 4.5% glucose. Fluid balance was monitored hourly. Just after introduction of the catheter a mean of 65 ml +/- 25 ml/kg ascites could be removed and the total quantity of removed fluid was 175 ml +/- 45 ml/kg bodyweight.(ABSTRACT TRUNCATED AT 250 WORDS)
Blood Pressure↗