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Biomedical subjects

J O Defraigne

Publications and source records attributed to J O Defraigne.

At least 127 records · Page 7Linked to original sources
PubMed1984

Isolation of follicular dendritic cells from human tonsils and adenoids. I. Procedure and morphological characterization.

Follicular dendritic cells have been isolated from human tonsils and adenoids and characterized at the ultrastructural level. Follicles were dissected and digested with different hydrolytic enzymes. The cells were separated by sedimentation at unit gravity. By this procedure we obtained follicular dendritic cells enveloping lymphocytes with their cytoplasmic extensions in a way analogous to that described for isolated thymic nurse cells. The ultrastructural features of isolated follicular dendritic cells are similar to those observed in situ. Prolonged enzymatic action caused loss of the enveloped lymphocytes.

Adenoids↗
PubMedDate not supplied

Oxidative stress in the liver and the brain of rats in fulminant hepatic failure.

The etiological mechanisms of brain edema in fulminant hepatic failure are incompletely understood. In a surgical model of fulminant hepatic failure in the rat, we tested whether oxidative stress may be involved in the early steps of brain edema. Moreover, we took advantage of this model to determine if oxidative stress may be involved in the hepatocyte dysfunction observed in the setting of fulminant hepatic failure. Oxidative stress was evaluated by measurement of tissue ascorbic acid in the brain and liver of rats at 6 hours after induction of fulminant hepatic failure versus in control or partially hepatectomized rats. After 6 hours, the level of ascorbic acid was not different in the brain tissue of the various groups, indicating no oxidative stress. The liver showed a significant decrease in ascorbic acid levels, both in ischemic and nonischemic liver tissue, suggesting that oxidative stress might be involved in the failure of liver regeneration in fulminant hepatic failure. In this rat model no oxidative stress was demonstrated in the brain during the early phase of fulminant liver failure.

Animals↗
PubMedDate not supplied

[Determination of plasma concentrations of antioxidants, antibodies against oxidized LDL, and homocysteine in a population sample from Liège].

A large number of epidemiological and clinical studies suggest that oxidative stress plays an important role in the development of cardiovascular diseases. In this way, following reference values in plasmatic antioxidants have been determined in a group of 123 blood donors (94 males, 29 females; age: 21-64 years) living in the surroundings of Liege, Belgium: vitamin A (1.5-3.62 mmol/l), vitamin C (3.68-75.21 mmol/l), vitamin E (16.98-46.46 mmol/l), ratio vitamin E/cholesterol (3.92-8.32 mmol/mmol), selenium (0.66-1.26 mmol/l), sulphydryl proteins (216-556 mmol/l), uric acid (174-477 mmol/l), superoxide dismutase (542-852 IU/g hemoglobine), glutathion peroxidase (39.55-91.83 IU/g hemoglobine). Only a few number of subjects were found with values corresponding to high risk of deficiency in antioxidants although low values in vitamin C (< 11.35 mmol/l) and in selenium (< 0.75 mmol/l) were respectively observed in 5.69 and 10.5% of our subjects. Autoantibodies against oxidized LDL, as marker of oxidative stress, and homocysteine, as a risk factor of atherosclerosis involved in the development of oxidative stress, have also been investigated. Approximatively 40% of the population presented values higher than the superior limit mean value (20.3% > 650 IU/l in autoantibodies and 19.5% > 15.2 mmol/l in homocysteine) that are, however, not correlated with age or low levels in antioxidants. The effect of smoking (25% of the population) contributed to significantly decrease vitamin C, selenium and glutathion peroxidase concentrations by 31.9 and 13% when compared to nonsmokers. Intake of 1 to 4 fruits per day resulted in a significant increase of 56.9% in vitamin C when compared to nonconsumers (26.8% of the population). In contrast, homocysteine concentrations were significantly decreased by 21.4% in fruits consumers. Thank to the development of methods allowing the routine dosage of all these parameters, general practitioners can now easily establish the oxidative stress status of their patients and, as fonction of getting patterns, detect populations at risk of developing cardiovascular diseases.

Adult↗
PubMedDate not supplied

Nicardipine protocol for CABG using the radial artery clinical and angiographic data.

The routine use of arterial grafts in coronary surgery is facilitated by peroperative adjunction of antispasmodic drug to reduce the event of spasm. Diltiazem has been favoured in most clinical studies devoted to the radial artery graft. The aim of this study was to assess the efficacy of a spasm preventing protocol associating hydrostatic dilation of the graft with a diluted solution of papaverine and nicardipine infusion, starting preoperatively and continued postoperatively in i.v. and per os forms. Between September 1996 and March 1997, a consecutive series of 50 patients underwent myocardial revascularization using the radial artery. The radial artery was prepared by hydrostatic dilation with papaverine (1%) and nicardipine was administrated at 0.25 microgram/kg/min and titrated according to the arterial systemic pressure. Operative mortality was 4% (sepsis). There was no evidence of perioperative MI nor hypoperfusion syndrome. Mean CKMB level at 18 hours was 36 micrograms/l. No ischaemic anomalies of the ECG were detected. Angiography performed in the last 20 patients showed a 98% (51/52) permeability rate for all graft; 19/20 radial grafts (95%) were patent. One radial graft presented a 50% stenosis at the proximal anastomosis, and another a moderate spasm (40%) in the middle part of the conduit. This study confirms that the radial artery conduit can be used with satisfactory results for routine coronary artery bypass. The use of nicardipine allows the control the vasoreactivity of the radial graft without totally obviating at least angiographic spasm. This drug is easy to titrate, and well tolerated in association to beta-blockers in the routine perioperative management of the coronary patients.

Coronary Angiography↗
PubMedDate not supplied

[Oxygen metabolism and toxicity in the phenomenon of ischemia-reperfusion].

One of the major cause of human disease results from the compromise of blood flow and oxygen delivery to tissues. Ischemia phenomenon is defined as blood flow that is inadequate to maintain normal tissue function. Prolonged ischemia ultimately results in irreversible changes in cell metabolism and cell death. Historically, it was felt that if ischemia results in altered cell function and injury, then reoxygenation or reperfusion leading to a restoration of a normal blood flow was expected to have a beneficial effect and promote salvage of tissue depending on the extent of ischemia. Recent studies have, however, revealed that reoxygenation leads to an oxygen metabolism resulting in the generation of active and toxic oxygen intermediates (free radicals) which play an important role in the pathophysiology of reperfusion injury.

Antioxidants↗
PubMedDate not supplied

Brachiocephalic arterial reconstruction.

From 1980 to 1990, 18 patients underwent trans-sternal repair for occlusive disease of the brachiocephalic artery. The mean age was 57 years (43-72). Most of the patients were women (n = 10). All but two patients had one or more symptoms related to the stenosis of the brachiocephalic trunk: right-sided upper limb ischemia (n = 7), transient ischemic attacks (n = 8), vertebrobasilar insufficiency (n = 6), left sided minor stroke (n = 1). Only two patients were asymptomatic before operation. Angiography revealed a tight stenosis (n = 14) or an occlusion (n = 3); in one patient it concerned an ulcerated non-stenotic plaque of the brachiocephalic artery. Eleven patients had coexistent involvement of other supraaortic vessels. Angiographically, clinically and intraoperatively, there was evidence of Takayasu arteritis in three female patients. All patients had direct repair by trans-sternal approach. Six patients with short lesions had thromboendarterectomy with patch angioplasty of the innominate artery. In eleven cases, aorto-brachiocephalic bypass grafting was performed. In one patient, aortic calcification precluded proximal anastomosis, and a carotid-to-carotid bypass was done. In five patients, simultaneous revascularization of subclavian (n = 3), left common carotid (n = 2) or internal carotid artery (n = 2) completed the procedure. In one patient, concomitant coronary revascularization was done. There was no operative mortality. Postoperative morbidity was limited to pulmonary infection (n = 2), transient neurologic deficit (n = 1) and renal insufficiency (n = 1). All patients had relief of symptoms. Duplex echo scan confirmed patency of all reconstructions at a mean follow-up of 46 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

[A central pathological mechanism explaining diabetic complications?].

Diabetes mellitus is associated to micro- and macro-vascular lesions responsible for myocardial infarction, nephropathy, retinopathy and polyneuropathy. Four main pathogenic mechanisms have been proposed, all associated with hyperglycaemia: 1) increased flux in the polyol pathway; 2) increased flux in the hexosamine pathway; 3) protein kinase C activation; and 4) increased formation of advanced glycation endproducts. A common mechanism seems to play a central role in the activation of these various pathways. Indeed, an increased production of free radicals by mitochondria induced by hyperglycaemia may be responsible for the observed metabolic disturbances. The present article describes that theory and presents its possible therapeutic implications.

Blood Glucose↗
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Axillounifemoral and axillobifemoral bypasses. Retrospective study of 85 cases.

From 1983 to 1990, 65 axillobifemoral and 20 axillofemoral bypasses have been performed in 85 patients (77 men and 8 women), with a mean age of 69 +/- 9 years. Indications for surgery were: severe aortoiliac occlusive disease (87%), sepsis of previous aortoiliac prosthesis, abdominal aorta aneurysm. Anatomic bypass was precluded for general (81%) or local (19%) conditions. In the last group, 9 patients have had previous laparotomy. Four patients presented with aortoenteric fistulas. Eighteen patients were operated on in emergency. The operative mortality was 12%, with 50% cardiac related deaths. Early primary patency was 98%. Early secondary patency was 100%. The mean follow-up is 28 +/- 15 months. The 3 years survival is 77%. The cumulative patency rates at 1 and 3 years are 89% and 76% respectively. Although axillobifemoral bypasses achieve poor long-term results when compared with aortoiliac bypasses, they can be considered in high risk patients. In this group of patients, the cumulative patency rate and the survival curves tend to be parallel.

Aged↗
PubMedDate not supplied

Truncal vagotomy and pyloroplasty combined with valvular replacement in patients with ulcer disease.

In 1988, 5 patients (3 men and 2 women) with ulcer disease (mean age 56 +/- 8 years) underwent valvular replacement for aortic (No. = 4) or mitral disease (No. = 1). All patients had had gastroduodenal ulcers. Preoperative gastroscopy demonstrated active ulcers (No. = 4) and a healed pyloric ulcer with pyloric stenosis (No. = 1). Despite the presence of ulcers, a non-biologic prosthesis was preferred in each patient because of their young age (No. = 3), chronic atrial fibrillation requiring anticoagulant therapy (No. = 1), and refusal of the eventuality of subsequent reoperation (No. = 1). In each patient, a truncal vagotomy with pyloroplasty was performed simultaneously with the valvular procedures by the same incision. The postoperative courses were uneventful. With a mean follow-up of 15 +/- 3 months, no gastrointestinal bleeding was observed during anticoagulant therapy. With anticoagulant drugs, bleeding may occur with a frequency of 4% per patient treatment-year, half of which are gastrointestinal in origin. Nevertheless, in selected patients with gastroduodenal ulcers, performing a vagotomy-pyloroplasty simultaneously with valvular replacement allows implantation of a non-biologic prosthesis, with greater durability than bioprosthesis.

Anticoagulants↗
PubMedDate not supplied

Surgical management of left atrial myxoma.

Although rare, left atrial myxoma is an entity from anatomopathological and clinical aspects. Seven cases of left atrial myxoma operated on the last ten years were reviewed. We also report a rare presentation of right atrial myxoma, where the tumor was responsible of a dramatic hemodynamic shock due to right ventricular inflow obstruction. Six patients were female, with a mean age of 53 years. All but one consulted for exertional dyspnea of recent onset. Two patients with left atrial myxoma and the patient with right atrial myxoma had experienced embolism. Five patients had systemic symptoms. Echocardiography was the most performant diagnostic procedure. All but the patient with right atrial myxoma were operated by the left atrial access. The mitral valve was replaced in two patients. The histological aspect of this benign tumor is illustrated but the lack of frank border between the tumor and the myocardium is emphasized. We conclude that surgical management is primordial. We give anatomopathological rationale for resection of implantation pedicle. The operative mortality was nul in this series of 8 patients; major improvement of cardiac status was constant. No recurrence has occurred during the follow-up period.

Adolescent↗
PubMedDate not supplied

Cardiac transplantation in patients older than 55 years.

From 1985 to 1990, 27 patients older than 55 years (extremes 55-65 years; 21 men and 6 women) received a cardiac transplant. The cause of cardiopathy was ischemic in 70%. Postoperative immunosuppressive therapy consisted of Cyclosporin A, steroids, azathioprine and antilymphocytic serum. Rejection episodes were monitored by endomyocardial biopsies and treated by pulses of steroids or monoclonal antibodies (OKT3). The operative mortality is 7.4% (n = 2). The one and two year survivals are 71% and 62% respectively. The incidence of infection and/or rejection were 0.71 +/- 0.4 and 1.4 +/- 0.7 episodes/patient year. Age beyond 55 years does not contraindicate heart transplantation. This change in recipient selection policy should lead to parallel changes in donor selection criteria.

Age Factors↗
PubMedDate not supplied

Carotid-subclavian bypass with or without carotid endarterectomy.

From 1981 to 1987, 29 patients (14 women and 15 men, with a mean age of 56 +/- 15 years) underwent a carotid-subclavian bypass for occlusive lesion of the subclavian artery (or of the left common carotid artery). The symptomatology included vertebrobasilar insufficiency, arm ischemic symptoms, or combination of both symptoms. Twelve patients (42%) have had a previous transient ischemic attack, or a cerebrovascular accident. There were 22 stenoses or occlusions of the left subclavian artery, and 6 of the right subclavian artery. On arteriography, 9 patients had significant associated lesions on the internal carotid artery, either homolateral (n = 7), or heterolateral, or bilateral. Carotid to subclavian bypasses were performed either with autogenous saphenous vein (n = 15), or with prosthetic graft (n = 14). In 5 cases, a carotid endarterectomy was done simultaneously to the bypass. Operative mortality was 3.4% (1/29). Early patency (less than 1 month) was 97% and late patency 89%, with a mean follow-up of 40 +/- 24 months. The patency rates were not significantly different whether a prosthesis or a vein was used for the bypass. All patients were improved and complete relief of symptoms was achieved in 92%. No patient experienced symptoms of carotid steal after the bypass. We concluded that carotid-subclavian bypass is a safe and efficient method for revascularization of the subclavian artery of of the left common carotid artery in selected cases.

Adult↗
PubMedDate not supplied

Valvular and coronary surgery in renal transplant patients.

The Authors report aortic valvular replacement (AVR) and coronary artery bypass graft surgery (CABG) successfully performed in two renal transplant patients. The postoperative blood urea and creatinine levels were comparable to the preoperative values. The first patient underwent isolated AVR. The second patient had an initial AVR combined with CABG followed two years later by a further AVR for prosthetic dysfunction. For many reasons, coronary artery (CAD) and valvular diseases are not uncommon in renal transplant patients. Cardiac surgery is feasible without impairment of the renal function provided some precautions are taken, ie good mean perfusion pressure during cardiopulmonary bypass (CPB), adequate volume replacement, and selected use of mannitol and dopamine.

Aortic Valve↗
PubMedDate not supplied

[Simultaneous coronary and carotid surgery: apropos of 73 cases].

A series of 73 simultaneous carotid and coronary revascularizations (Group I) is presented (January 1980-December 1988). Age, sex, risk factors, severity of angina, coronarography, neurological symptoms, angiographic carotid lesions and operative outcome of these 73 patients are compared with the aspects of 3544 coronary bypass patients (Group II) and 1001 carotid endarterectomized patients (Group III) during the same period. The angina in Group I is more severe, with 22% belonging to NYHA class IV and 26% having a stenosis of the left main coronary artery, vs 14% and 13% in Group II. Seventy percent of the carotid lesions in Group I are asymptomatic vs 33% in Group III. Group I patients had more problems in the perioperative period, with 16.4% needing prolonged high-doses analeptics and 5.4% intraaortic counterpulsation balloon. Operative mortality is higher (7%) in Group I compared with Group II (2.3%) and Group III (1.7%). These results permit to define a population of polyvascular patients with concomitant coronary and carotid disease, characterized by a more diffuse atherosclerosis and a higher operative risk. Operative morbidity and mortality after combined myocardial and cerebral revascularization remains nevertheless inferior to the cumulated surgical risk of the sequential procedures (74 patients with coexistant coronary and carotid lesions operated in two sessions before 1986).

Carotid Artery Diseases↗
PubMedDate not supplied

Combined one stage cardiac and pulmonary surgery by median sternotomy.

From 1985 to 1989, 6 patients underwent a pulmonary surgical procedure simultaneously with a cardiac operation. All patients were male with a mean age of 60 +/- 8 years. The cardiac procedures included: 1 aortic and 1 mitral valve replacement, 3 coronary artery bypass grafts and 1 closure of an atrial septal defect. Four patients had primary pulmonary nodules: 2 bronchogenic carcinomas and 2 benign hamartomas. They presented with cardiac symptoms, and lung nodules were incidentally found on preoperative Chest X-Rays. The 2 last patients had pulmonary metastases of colonic neoplasms previously resected, respectively 3 and 6 years before. After completion of the cardiac procedures, during the rewarming of the patient, the pulmonary resection was performed on a deflated lung, via the median sternotomy. Pulmonary procedures included: right upper segmentectomy (n = 1), left pneumonectomy (n = 1), left interior lobectomy (n = 1), right middle lobectomy (n = 1), left upper wedge resection (n = 1), and right upper lobe wedge resection (n = 1). All patients were extubated on day one. One patient died from rythm disturbances on day 13. All other patients are alive with a mean survival of 30 months. The authors conclude that combined surgery is feasible in selected cases. Sternal approach is not a limitation to pulmonary resection.

Aged↗
PubMedDate not supplied

Renal autotransplantation: a kidney-saving procedure.

The authors report their recent experience with renal autotransplantation (3 cases). In one case it concerned a complex aneurysm of the renal artery involving secondary arterial renal branches, and associated with hydronephrosis (case 1); another patient presented a high ureteral injury unsuccessfully repaired by previous surgery (case 2), and the third patient had diffuse fibrodysplasia of intrahilar arterial branches (case 3). The procedures were technically successful and gave good functional results. They describe the technique of kidney refrigeration, extracorporeal vessel repair and ureteral preservation or reimplantation. Indications and technical advantages of this organ-saving reconstructive approach are discussed.

Adult↗
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[Lymphangiosarcoma following mastectomy: review of the literature apropos of 2 recent cases of Stewart-Treves syndrome].

Two cases of lymphangiosarcomas which arose 4 and 14 years after a mastectomy are reported (Stewart-Treves syndrome). One of the patients was treated by shoulder disarticulation and the other by chemotherapy (using Melphalan, Cyclophosphamide and 5-fluorouracil). Disseminated metastases and deaths occurred 6 and 18 months after the onset of the lesion. Stewart-Treves syndrome occurs in approximately 0.07 to 0.45% of mastectomy. Prognosis is worse: survival at five year is fewer than 10%. Early diagnosis is mandatory. Surgical resection of the lesions and adjunctive chemotherapy seem the best treatment.

Aged↗