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Biomedical subjects

J N Fabiani

Publications and source records attributed to J N Fabiani.

At least 73 records · Page 4Linked to original sources
PubMed1998

[Treatment of false aneurysm of the ascending aorta under circulatory arrest and the Port-access system].

Pseudo-aneurysms of the ascending aorta after thoracic surgery are rare and pose a problem of surgical strategy with respect to the approach, the myocardial protection and type of repair. The authors have solved the problem by using a new technology, the Post-Access TM system, which, by simply introducing a catheter into the femoral artery, allows endoaortic clamping, the administration of cardioplegic solution, and the drainage of the left heart chambers. The system was used with a good result for treating a pseudo-aneurysm of the proximal anastomosis of a bypass between the ascending aorta and the innominate artery, limiting the duration of circulatory arrest and reducing blood loss.

Aged↗
PubMed1997

Radiation-induced arterial disease of the lower limb.

We describe a case of radiation injury to the superficial femoral and upper popliteal arteries in a 39-year-old man treated 13 years earlier for an osteosarcoma of the right femur. Following two failed attempts at transluminal angioplasty, a saphenous vein femoropopliteal bypass graft was performed successfully. A comprehensive review of the literature on radiation-induced arterial injury to the limbs is presented with a discussion of the different management options. Percutaneous transluminal balloon angioplasty seems to have no place in the treatment of such lesions.

Adult↗
PubMed1997

Video-assisted aortofemoral bypass: results in seven cases.

Between September 1995 and February 1996 we attempted to perform video-assisted aortofemoral bypass in nine patients. All patients were male with a mean age of 58.7 years, mean weight of 64.7 kg, and mean height of 1.69 m. In two patients it was necessary to switch to open laparotomy due to inadequate aortic exposure in one and extensive aortic calcification in the other. Aortobifemoral bypass was performed by the transperitoneal approach in three patients and unilateral aortofemoral bypass by the retroperitoneal approach in four patients. Exposure was more difficult by the transperitoneal approach. Postoperative graft patency was excellent in all patients. Video-assisted surgery did not shorten the delay to resumption of intestinal transit but it did reduce the duration of hospitalization and need for postoperative analgesia. Our experience suggests that video-assisted aortofemoral bypass without laparotomy can be performed and that it allows more rapid patient recovery.

Adult↗
PubMed1997

Inhibition of intimal hyperplasia by an antisense oligonucleotide of farnesyl transferase delivered endoluminally during iliac angioplasty in a rabbit model.

The major complication of vascular recanalization is intimal hyperplasia which is due mainly to proliferation and migration of smooth muscle cells (SMC). Activation of SMC results from stimulation of protooncogens (c-myb, c-myc, c-fos) by growth factors induced by activated ras-proteins. Ras-proteins become activated after receiving a farnesyl group in a reaction catalyzed by famesyl transferase. The purpose of this study was to test the effectiveness in preventing intimal hyperplasia of an antisense oligonucleotide of the alpha subunit of farnesyl-transferase delivered endoluminally during angioplasty of the common iliac artery in rabbit model. Twenty-one male New Zealand rabbits with a mean weight of 3.3 kg fed a high cholesterol diet underwent bilateral angioplasty of the common iliac artery using hydrogel-coated balloon catheters. On the right side three types of treatment were randomly performed by adding one of the following three oligonucleotides to the hydrogel precoating:antisense oligonucleotide of farnesyl transferase (n = 7), mismatch oligonucleotide (n = 7), and scramble oligonucleotide (n = 7). On the left side hydrogel was used with saline so that each animal served as its own control. Animals were killed 6 weeks after angioplasty and arteries were studied. The thickness and mean surface of the neointima (MTI and MSI) and the ratio (R) of the neointima to neointima + media were calculated. In the scramble and mismatch groups there was no difference between the treated and control arteries with regard to MTI, MSI, or R. In the antisense group mean all three values were significantly lower on the treated side than the control side (EMI: p < 0.02, SMI: p < 0.02, and R: p < 0.01). Treated arteries in the antisense group presented significantly lower EMI (p < 0.02), SMI (p < 0.02), and R (p < 0.01) than treated arteries in the other groups whereas the thickness and mean surface of the media were comparable. Endoluminal administration of an antisense oligonucleotide against the alpha subunit of farneysyl transferase inhibited intimal hyperplasia in our model.

Alkyl and Aryl Transferases↗
PubMed1997

Dynamic cardiomyoplasty: clinical follow-up at 12 years.

OBJECTIVE: The purpose of this study is to evaluate the long-term outcome of dynamic cardiomyoplasty. This surgical technique was conceived to assist the failing heart. The many proposed mechanisms of action of cardiomyoplasty are: (1) systolic assist; (2) limitation of ventricular dilation; (3) reduction of ventricular wall stress (sparing effect); (4) ventricular remodeling with an active girdling effect; (5) angiogenesis; and (6) a neurohumoral effect. METHODS: We investigated 95 patients in our hospital undergoing this procedure due to severe chronic heart failure, refractory to optimal medical treatment. Patients had a mean age of 51 +/- 12 years. The etiology of heart failure was ischemic 55%, idiopathic 34%, ventricular tumor 6%, and other 5%. The mean follow-up was 44 months. RESULTS: The mean New York Heart Association (NYHA) functional class improved postoperatively from 3.2 to 1.8. Average radioisotopic left ventricular (LV) ejection fraction increased from 17 +/- 5 to 27 +/- 4% (P < 0.05). Stroke volume index increased from 32 +/- 7 to 43 +/- 8 ml/beat per m2 (P < 0.05). The heart size remained stable over the long term. Following cardiomyoplasty, the number of hospitalizations due to congestive heart failure was reduced to 0.4 hospitalizations/patient per year (preoperative: 2.5, P < 0.05). Computed tomography scans showed at long term a preserved latissimus dorsi muscle structure in 84% of patients. Survival probability at 7 years is 54%. Six patients underwent heart transplant after cardiomyoplasty (mean delay: 25 months), due to the natural evolution of their underlying heart disease. There were no specific technical difficulties. CONCLUSIONS: Clinically, this procedure reverses heart failure, improves functional class and ameliorates quality of life. The latissimus dorsi muscle histological structure is maintained at long-term, when postoperative electrostimulation is performed, avoiding excessive stimulation. Cardiomyoplasty may delay or prevent the progression of heart failure and the indication of cardiac transplantation.

Actuarial Analysis↗
PubMed1997

[Effects on myointimal proliferation of an antisense oligonucleotide directed against c-myb: specificity of action and consequences on vasoreactivity].

Several reports have shown that an antisense oligonucleotide directed against c-myb (AS 18) inhibits the proliferation of smooth muscle cell. The aims of this study were to confirm the specificity of a new c-myb antisens and to evaluate changes in vasoreactivity following treatment with a c-myb antisense. Five groups of rats were constituted. All underwent desendothelialisation of the abdominal aorta. A solution containing pluronic gel, or one of the following oligonucleotides: AS 18, 15 mere antisense directed against c-myb, an aleatory 4G sequence containing 4 consecutive guanosines, a 15 mere antisense mismatch (n = 11), was applied around the aorta. After 21 days, the thickness and mean surface areas of the media and intima were calculated. Four groups of rats were constituted for the reactivity study: control (A), desendothelialisation (B), desendothelialisation + application of AS 18 (C), and application of AS 18 alone (D). One ring per aorta was sampled at the 21st day and analysed in an organ chamber. The following results were obtained: the thickness and average surface areas of the intima were smaller (p < 0.05) in the 4G and AS 18 groups; in group B, none of the 8 segments responded to acetylcholine; in group C, 6 out of 8 segments responded. The contraction study showed no difference between groups A and D or between B and C. The mode of action of AS 18 antisense of c-myb is non specific but due to the presence of 4 consecutive guanosines in the oligonucleotide. Oligonucleotide with this sequence inhibits myo-intimal hyperplasia and improves endothelium-dependent relaxation in this model without affecting the contraction.

Animals↗
PubMed1996

Homograft replacement of the mitral valve. Graft selection, technique of implantation, and results in forty-three patients.

UNLABELLED: Because of experience gained in reconstructive mitral valve surgery, we have reevaluated the implantation of cryopreserved homografts in the mitral position. Forty-three patients, aged 11 to 69 years (mean 34 years), underwent mitral valve replacement with cryopreserved mitral homografts. The indications for the procedure were acute endocarditis (n = 14), rheumatic stenosis (n = 26), systemic lupus endocarditis (n = 2), and marasmic endocarditis (n = 1). All homografts were obtained from hearts explanted in the course of transplantation and were cryopreserved at -160 degrees C in 10% dimethyl sulfoxide solution without antibiotics. Appropriate sizing was based on morphologic study of the homografts and preoperative echocardiographic assessment of the recipient valve. In 82 homografts analyzed, the height of the anterior leaflet was 25 +/- 3 mm and the distance from the anulus to the apex of the anterior papillary muscle was 21 +/- 3 mm. The morphologic features of the papillary muscles were classified according to four types of increasing complexity. Nine valves with complex (type IV) papillary muscle abnormalities were discarded. Echocardiographic measurements of the valve were matched with those of the homograft identification cards and a slightly larger homograft was selected (measurements + 3 mm). Partial homograft replacement was done in case of a localized lesion (abscess or calcification) (n = 21). Total homograft replacement was undertaken in the presence of diffuse lesions (n = 22). Two hospital deaths occurred as a result of poor cardiac output. One patient required reoperation on the tenth postoperative day after a dehiscence on the valvular suture line. After a mean follow-up of 14 months, there has been one late death caused by a bronchial neoplasm and one reoperation for residual stenosis (partial replacement). The remaining patients were in either New York Heart Association class I (n = 25) or II (n = 13). Thirty-three patients were in sinus rhythm. Follow-up echocardiography has revealed no mitral regurgitation (n = 20), minimal mitral regurgitation (n = 13), and mild mitral regurgitation (n = 5). Surface valve area has been calculated at 2.5 +/- 0.4 cm2 in partial homograft reconstruction and 2.7 +/- 0.3 cm2 in total homograft replacement, with a transvalvular gradient of 3 +/- 4 mm Hg. CONCLUSION: In a selected group of patients, the use of mitral homografts significantly extended the present limitations of reparative surgery of the mitral valve.

Adolescent↗
PubMed1996

Improvement of postischemic renal function by limitation of initial reperfusion pressure.

PURPOSE: This study was designed to determine whether lowering the initial reperfusion pressure can improve renal function after ischemia. MATERIALS AND DESIGN: Sixty minutes of warm renal ischemia was induced in 2 groups of 8 minipigs by clamping the left renal artery. Right kidneys were kept in situ as controls. In the standard reperfusion group, ischemic kidneys were immediately reperfused at systemic pressure. In the controlled reperfusion group, the renal artery reperfusion pressure was maintained at 60 mm. Hg for the initial 20 minutes of reperfusion by use of a regulating pump and then at systemic pressure for the next 100 minutes. RESULTS: On the basis of the postischemic anuria rate, glomerular filtration rate and renal histology, renal tolerance to ischemia was significantly improved in the controlled reperfusion group. CONCLUSION: These findings of improved renal function recovery after warm ischemia by controlled low reperfusion pressure may have clinical relevance to the reperfusion technique used after renal transplantation in humans.

Animals↗
PubMed1996

[Coronary assessment and surgery for aortic aneurysm: systematic coronarography].

Epidemiologic studies have shown that patients with peripheral vascular disease have a high risk of coronary heart disease. The vascular surgeon must therefore search for latent lesions which might lead to decompensation during or after the surgical procedure. Coronarography can be proposed in symptomatic patients or those with a past history of coronary heart disease, but such an indication is questionable for asymptomatic patients. Non-invasive exploration could theoretically provide information of the coronary risk but are not always possible or reliable in patients with peripheral vascular disease. A practical attitude can be established by analyzing the lesions on the basis of large international series. Cardiac exploration evaluating ischaemia can be proposed after the initial work-up to establish management strategy for intermediary cases.

Aortic Aneurysm↗
PubMed1996

[Effects of an anti-c-myb antisense oligonucleotide on myo-intimal proliferation. Specificity of action and consequences on vasoreactivity].

Several reports have shown that an 18-mere antisense oligonucleotide directed against c-myb (AS 18) inhibits the proliferation of smooth muscle. The aims of this study were to confirm the specificity of a new anti-c-myb antisense and to evaluate changes in vasoreactivity following treatment with a c-myb antisense. Five groups of rats. All underwent desendothelialisation of the abdominal aorta. A solution containing pluronic gel, or one of the following oligonucleotides: AS 18, 15 mere antisense directed against c-myb, an aleatory 4G sequence containing 4 consecutive guanosines, a 15 mere antisense mismatch (n = 11), was applied around the aorta. After 21 days, the thickness and mean surface areas of the media and intima were calculated. Four groups of rats were constituted for the vasoreactivity study: control (A), desendothelialisation (B), desendothelialisation + application of AS 18 (C) and application of AS 18 alone (D). One ring per aorta was sampled at the 21st day and analysed in an organ chamber. The following results were obtained: the thickness and average surface areas of the intima were smaller (p < 0.05) in the 4G and AS 18-groups; in group B, none of the 8 segments responded to acetylcholine; in group C, 6 out of 8 segments responded. The contraction study showed no differences between groups A and D or between groups B and C. The authors conclude that the mode of action of AS 18 antisense of c-myb is non-specific but due to the presence of 4 consecutive guanosines in the oligonucleotide. Oligonucleotide with this sequence inhibits myo-intimal hyperplasia and improves endothelium-dependent relaxation in this model without affecting the contraction.

Animals↗
PubMed1996

[Pre- and intraoperative management of heparin cross hypersensitivity. Apropos of a case].

A patient with a Starr prosthetic heart valve for 13 years developed chronic idiopathic thrombocytopaenic purpura and a highly probable crossed allergy to heparin. As the valve needed to be replaced, cardiopulmonary bypass surgery was undertaken associating heparin with lioprost and Aprotinine. In this type of situation, aggregation of control platelets by the patient's plasma in the presence of unfractionated heparin and of low molecular weight heparin justifies the use of powerful antiplatelet agents such as lioprost which was associated with Aprotinine for its platelet protective effects. This original combination allowed successful cardiopulmonary bypass surgery under unfractionated heparin under excellent conditions with minimal blood loss. This case underlines the value of this approach for cardiopulmonary bypass surgery in patients with heparin-induced thrombocytopaenia.

Adult↗
PubMed1995

Carpentier-Edwards pericardial bioprosthesis in aortic position: long-term follow-up 1980 to 1994.

Aortic valve replacement with Carpentier-Edwards pericardial bioprosthesis was associated with excellent midterm clinical results. Long-term evaluation, however, remained to be determined. We reviewed the first 124 patients who underwent aortic valve replacement with a Carpentier-Edwards bioprosthesis at the Hôpital Broussais between 1980 and 1985. There were 67 males (54%) and 57 females (46%). The mean age at operation was 65 years (range, 18-83 years). The operative mortality (30 days) was 4%. All but 2 patients were followed up for an average of 7.7 years and a total of 973 patient years. There were 45 late deaths (4.7%/patient-year) of which 16 were valve-related (1.7%/patient-year). The actuarial survival rate was 49.9% at 12 years. The actuarial rate for freedom from valve-related mortality was 78.3% at 12 years. There were 7 thromboembolic events in 5 patients and 3 anticoagulation-related hemorrhages. Freedom from structural valve deterioration was 100% at 12 years and 83.3% at 13 years. We conclude that implantation of Carpentier-Edwards pericardial bioprosthesis in aortic position is associated with an excellent long-term clinical outcome. It is believed that the improved results of this valve result from the following original features: fully flexible stent, distensible struts, infrastent tissue mounting, optimal tissue orientation, and improved preservation.

Actuarial Analysis↗
PubMed1995

The autologous tissue cardiac valve: a new paradigm for heart valve replacement.

This is a report of early clinical experience with an autologous tissue cardiac valve, which demonstrates the feasibility of making a bioprosthesis in the operating room in 10 minutes at the time of the valve replacement operation. There were 30 implant patients (18 men, 12 women), with ages ranging from 32 to 83 years. Diagnoses included calcified aortic stenosis (n = 16), pure aortic insufficiency (n = 9), and mixed aortic stenosis and insufficiency (n = 5). Associated diagnoses have included chronic renal failure treated with dialysis (n = 1), coronary artery disease requiring concomitant coronary bypass (n = 1), ascending aortic aneurysm requiring resection (n = 3), and mitral insufficiency requiring concomitant mitral valvuloplasty (n = 2). All of the valve replacements were in the aortic position. These implanted patients are being followed up carefully according to the protocol that requires examination every 6 months for the first year and every 12 months subsequently. No patient has been lost to follow-up. Twenty-seven patients are alive and well from 1 to 22 months postoperatively. There were three deaths: two perioperative deaths (one perivalvular leak and one hemorrhage) and one infective endocarditis 1.3 years after valve replacement. All surviving patients were followed up by echocardiographic examination (mean gradient, 15.5 +/- 6.8 mm Hg at 1 year). In conclusion, the feasibility of this method and concept has been demonstrated with implants in 30 patients. The validity of the technique will be judged by clinical results and experiences in children.

Adult↗
PubMed1995

Plasma from patients exposed to ischemia reperfusion contains clastogenic factors and stimulates the chemiluminescence response of normal leukocytes.

Clastogenic factors (CFs) are released by cells exposed to superoxide radicals and are found in various situations of oxidative stress. Certain of their components stimulate further superoxide production by competent cells, as shown with cytochrome c assay in previous work. In the present study, we report CF formation after ischemia reperfusion in patients undergoing coronary bypass surgery. Plasma ultrafiltrates, collected 20 min after reperfusion, had clastogenic properties in contrast to those collected before ischemia. We also show that the luminol-enhanced chemiluminescence response of neutrophils from healthy persons is increased when these cells are exposed to CF-containing postreperfusion samples from patients. Light emission was reduced to control values in the presence of superoxide dismutase. The burst of oxyradicals upon reperfusion is probably the initiating event of CF formation, which in turn leads to further oxyradical generation. This amplification process may explain why detectable levels of CF need a delay of at least 10 min. The activated state of neutrophils in ischemia reperfusion is at once a consequence and a source of CFs. Individual variation in the persistence of this clastogenic and leukocyte-activating material was observed. Therefore, antioxidants for prevention of ischemia reperfusion injury should be continued during the postoperative course.

Antioxidants↗
PubMed1995

Improvement of postischemic kidney function by reperfusion with a specifically developed solution (BT01).

Reperfusion is a critical phase of organ preservation. The purpose of this study was to develop a solution specifically for postischemic kidney reperfusion. Unilateral left normothermic kidney ischemia was induced for 60 minutes in two groups of micropigs. In group 1 (control pigs, n = 6) the kidney was reperfused immediately with pure blood at systemic pressure by unclamping the renal artery. In group 2 (test animals, n = 6) the kidney was initially reperfused with an intracellular flush solution enriched with solution BT01 composed of cytoprotectors (natriuretic factor, PGI2), free radical chelating agents (allopurinol, mannitol), and substrates for the mitochondrial respiratory chain (aspartate, glutamate). This solution was mixed immediately before use with blood in a ration of 1:4 parts and injected into the left renal artery with a perfuser at a constant pressure of 60 mm Hg. After 20 minutes, the kidney was reperfused with systemic blood for 100 minutes. Glomerular filtration rate (GFR) was determined by measuring inulin clearance. Kidney blood flow was measured throughout the experiment. After 120 minutes of reperfusion, the kidneys were removed for histologic examination. In the control pigs (group 1) 50% of the animals were anuric. The ratio between GFR measured in the left kidney at the end of perfusion and at equilibrium in the remaining animals was 0.16 +/- 0.01. In test animals (group 2) all animals recovered diuresis. The ratio between GFR measured in the left kidney at the end of perfusion and equilibrium was 0.51 +/- 0.12 (p < 0.001, group 2 vs. group 1). In group 2 postperfusion kidney blood flow was higher than in group 1 (63.0 ml/min vs. 27.4 ml/min; p < 0.05) because of a decrease in renal vascular resistance. Light microscopic examination of kidneys form animals in group 1 revealed tubular necrosis that extended to the parenchyma, with exposure of tubular interstitium. In group 2 only degenerative lesions with edema of tubular cells and disappearance of brush borders were observed. Our findings indicate that flushing the kidneys with BT01 solution mixed with blood improves postischemic kidney function by reducing reperfusion damage.

Animals↗