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Biomedical subjects

B Andreassian

Publications and source records attributed to B Andreassian.

At least 19 recordsLinked to original sources
PubMed2001

Adrenocortical carcinomas: surgical trends and results of a 253-patient series from the French Association of Endocrine Surgeons study group.

Because of the rarity of adrenocortical carcinoma, survival rates and the prognosis for patients who have undergone operation are not well known. The purpose of the French Association of Endocrine Surgery was to evaluate these factors over an 18-year period. A trend study was associated to assess changes in the clinical and biochemical presentations as well as the surgical evolution. A total of 253 patients (158 women, 95 men) with a mean age of 47 years were included. Cushing syndrome was the main clinical presentation (30%), and hormonal studies revealed secreting tumors in 66% of the cases. Altogether, 72% (n = 182) of patients underwent resection for cure, and 41.5% (n = 105) of them had an extensive resection because of metastatic cancer. A lymphadenectomy was performed in 32.5% (n = 89) of the cases. The operative mortality was 5.5% (n = 14). Patients were given mitotane as adjuvant therapy in 53.8% of the cases (n = 135). The results of staging were stage I in 16 patients (6.3%), stage II (local disease) in 126 patients (49.8%), stage III (locoregional disease) in 57 patients (22.5%), and stage IV (metastases) in 54 patients (21.3%). Neither tumor staging nor the rate of curative surgery changed during the study period. More subcostal incisions were performed, and the use of mitotane increased significantly. The 5-year actuarial survival rates were 38% overall, 50% in the curative group, 66% for stage I, 58% for stage II, 24% for stage III, and 0% for stage IV. Multivariate analysis showed that mitotane benefited only the group of patients not operated on for cure. A better prognosis was found in patients operated on after 1988 (p = 0.04), in those with precursor-secreting tumors (p = 0.005), and in those at local stages of the disease (p = 0.0003). Thus mitotane benefited only patients not operated on for cure. Curative resection, precursor secretion, recent diagnosis, and local stage were favorably associated with survival.

Adolescent↗
PubMed1999

In vitro endothelialization of PTFE vascular grafts: A comparison of various substrates, cell densities, and incubation times.

To establish the optimal conditions for achieving endothelial cell coverage of the luminal surfaces of small-caliber vascular grafts in vitro, the attachment of endothelial cells (ECs) cultured from human umbilical veins to polytetrafluoroethylene (PTFE) grafts was studied. Cell attachment and spreading were compared after PTFE grafts were (a) precoated with fibronectin (HFN), type I collagen, type IV collagen, plasma and fibrin with or without thrombin, singly or in combination; (b) seeded with cell densities varying from 0.5 x 10(5) to 6 x 10(5) cells/cm2; and (c) incubated at 30, 60, or 90 min. Cell coverage and spreading were assessed by means of scanning electron microscopy. Quantification of graft surface coverage was performed with computer-assisted image analysis. To determine optimal conditions of endothelialization among the 189 treatment combinations, analysis of variance was used. We conclude that a virtually confluent cell monolayer can be established on small-caliber PTFE grafts when precoated with fibrin glue or plasma, seeded with cell densities >/=4 x 10(5) cells/cm2, and incubated for 60 min. These parameters are compatible with an operating room vascular procedure.

Blood Vessel Prosthesis↗
PubMed1996

[Pulmonary emphysema: surgical indications].

Surgery for pulmonary emphysema, with the exception of lung transplantation, is limited at present to resection of the emphysematous areas. The resection of a unique bulla within an otherwise healthy parenchyma can be indicated in case of complications but rarely in asymptomatic patients. When the bullae are large (i.e. volume greater than one-third of the hemithorax) in a patient suffering from diffuse emphysema, bullectomy is the ideal indication. Mortality varies from 0 to 10%, essentially due to infection or acute respiratory failure. In most patients, the subjective improvement in terms of dyspnea and the objective improvement as measured by spirometry remains significative up to 5 years after surgery. Inversely, surgical resection is classically considered to be contraindicated in patients with small poorly-limited bullae. Recent data would however question this idea since subjective and objective improvement after reduction of the lung volume is still present 1 year after surgery in most patients, even those with severe obstruction. The mechanism is probably related to increased elastic recoil. Even if only temporary improvement can be achieved for a few years, the persisting course of emphysema would suggest that volume reduction should always be entertained as an alternative before lung transplantation.

Humans↗
PubMed1996

Elution of six antibiotics bonded to polyethylene vascular grafts sealed with three proteins.

The elution of six antistaphylococcal antibiotics from vascular polyethylene grafts sealed with albumin, gelatin, or collagen were studied in an in vitro system. The antibiotics tested were pefloxacin, vancomycin, teicoplanin, fusidic acid, pristinamycin, and rifampicin. The grafts were impregnated by simple soaking in antibiotic (1 mg/ml). The data were fitted to an exponential model and antibiotic half-lives (t1/2) were calculated from the regression lines. All the antibiotics tested were bound to the protein sealants. Antibiotic release varied with the type of antibiotic and the sealant. Rifampicin was eluted most slowly, particularly with albumin- and gelatin-sealed grafts, with t1/2 at 4-5.5 hr and antibiotic activity was still found at 48 hr. The glycopeptides were also eluted more slowly from albumin or gelatin sealant than from collagen. Although large quantities of glycopeptides were initially bound, they were quickly eluted (t1/2 = 30-44 min) and there was no residual antibiotic activity at 24 hr. Pefloxacin, pristinamycin, and fusidic acid bound to collagen or gelatin sealants were the most rapidly eluted, with t1/2 of 3-14 min, but they were eluted more slowly from albumin-sealed grafts, with t1/2 of 22-90 min. In vitro studies can be useful for evaluating the binding of antibiotics to protein-sealed grafts before animal experiments or human testing.

Albumins↗
PubMed1996

[Blood salvage: a conditional safety].

Recovery of shed blood is part of the allogenic blood saving policy of particular importance even though the risk of viral infection via transfusion has been considerably reduced. Blood transfusion requirements in vascular surgery are discussed together with alternatives to allogenic transfusion. Differed withdrawal of autologous blood can involve pre-operative autologous plasmapheresis and cytapheresis. Per-operative haemodilution is another variant of pre-operative isovolemic haemodilution and erythrocytapheresis. Recovery of shed blood can be done with or without lavage. Technical and pharmacologic measurements complete the method. Simultaneous use of different techniques can be useful. Recovery is particularly interesting in highly haemorhagic vascular procedures or those which must be done quite rapidly. Care must be taken to avoid the "recovery syndrome". Improvement in material will assure safety.

Blood Transfusion, Autologous↗
PubMed1995

[Treatment of primary hyperhidrosis of the upper limbs by transthoracic endoscopic sympathectomy].

Primary hyperhidrosis of the upper limbs has an important impact on the subject's social and psycho-affective equilibrium. These patients have two main problems. First physicians are not sufficiently aware of the therapeutic possibilities and secondly the generally poor reputation of surgery in this indication. Transthoracic endoscopic sympathectomy has completely changed the treatment of hyperhidrosis of the upper limbs. It is now considered to be the reference treatment in severe cases. The surgical procedure is simple and allows simultaneous treatment of both sides. There is no mortality and morbidity is extremely low quantitatively and of little consequence qualitatively. The therapeutic protocol is short and immediate and long-term results are excellent in 98 to 100% of the patients.

Arm↗
PubMed1995

[New techniques in thoracic surgery. I].

Progress over the last 40 years has greatly reduced morbidity and mortality in the constantly changing field of thoracic surgery. The first part of this review focuses on current indications and limitations in lung surgery. Technical procedures for pneumonectomy, lobectomy, bronchial resection and conservative surgery are well established. Although major respiratory or cardiac failure still limit indications bronchogenic cancer extension is no longer a contraindication. Exeresis after 70 years of age is not an exception. Surgery for non-small cell lung cancer has given promising results with a 5-year survival rate of 60-80% for patients in stage I and II. For stage III, two recent comparative studies have demonstrated the effectiveness of preoperative adjuvant chemotherapy which should logically be proposed with or without radiotherapy in patients with resectable tumours. Surgical removal of lung metastases and mesotheliomas has also made considerable progress. Unfortunately, except for therapeutic trials, exeresis of small cell lung cancer does not provide any beneficial effect and cannot be proposed. Indications for surgery in patients with chronic obstructive pulmonary disease however has been quite successful and now goes beyond classical exeresis of large compressive bullae. In many situations patients with diffuse emphysema can benefit from surgical reduction in lung volume before proposing transplantation. Lung transplantation is indicated for pulmonary fibrosis, pulmonary vascular disease and obstructive lung pulmonary disease with an overall survival rate of 50% at 5 years and 43% at 6 years. The rate of successful bilateral lung transplantation for cystic fibrosis remains to be determined.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1995

Mucosal T-lymphocytes in central airways of lung transplant recipients.

The immunohistochemical profile of mucosal lymphocytes was investigated in the central airways of lung transplant recipients. Bronchial and transbronchial biopsies (BB and TBB, respectively) and bronchoalveolar lavage for culture of bacteria and viruses were performed during a fibroscopic procedure in patients without evidence of chronic rejection, 3 to 10 mo after surgery. Analysis was restricted to samples without concurrent airway infection: 23 pairs of BB and TBB from 18 transplant recipients were analyzed. An immunohistochemical technique was used to identify and score mucosal cells that reacted with monoclonal antibodies against CD4, CD8, CD45-Ro (memory T-cells), and HLA-DR molecules. The same procedure was applied in nine nonsmoking control subjects (NS group). Data from transplant recipients were allocated to R+ (n = 11) or R- groups (n = 12), depending on the presence or absence of histologic evidence of acute rejection on TBB. A statistically significant depletion of every immunoreactive cell subset was observed in the R+ and the R- groups, but not in the NS group. Conversely, no significant difference for either score of immunoreactive cells were found between R+ and R- groups. The immunosuppressive regimen is suspected to play to play a major role in this depletion of bronchial mucosal T-cells. The acute lung rejection process does not appear to affect concurrently the immunohistochemical profile of immunoreactive cells in the bronchial mucosa.

Biopsy↗
PubMed1995

[Post-lung transplantation bronchiolitis obliterans].

Bronchiolitis obliterans is an anatomical lesion with multiple aetiologies. In the lung transplant patient the pure forms of bronchiolitis obliterans are probably the consequence of a process of chronic rejection; in fact necropsy tissue or lungs removed which have been transplanted show that the lesions of bronchiolitis obliterans are often associated with parenchymal disorders, vascular and proximal bronchial disease, which are sequelae of phenomena of rejection or infection. The effect of bronchiolitis obliterans on lung function is constant; this may appear progressively or in stages. Increasing immunosuppressive treatment may arrest the progress. This rarely occurs and the development of respiratory failure tends to be the rule. It is exceptional to achieve the diagnosis of bronchiolitis obliterans from the examination of a transbronchial biopsy. It is a combination of features, both clinical and respiratory function, negative bacteriology and virological investigations as well as the absence of any efficacy of conventional treatment for rejection which leads to the diagnosis. In certain cases the question of a pulmonary re-transplantation is raised.

Bronchiolitis Obliterans↗
PubMed1994

[Use of myoplasty after acute mediastinitis occurring after heart surgery. Apropos of 167 cases].

Infected median sternotomy often requires open wound management. A large thoracic defect usually results in subsequent exposure of heart, great vessels, aorto-coronary bypass grafting or vascular prosthesis. After thorough wound debridement, coverage with muscle transposition was carried out in a series of 167 cases observed over a period of 10 years. Transposition of both pectoralis major muscles on internal pedicles was performed in 75 cases. In 27 of these cases, internal mammary grafting did not preclude their use. Since 1986, intrathoracic transposition of the trapezius muscle has been our treatment of choice in 25 cases, most frequently combined with a double pectoralis major transposition. Rectus abdomini muscle flap was seldom used alone whereas latissimus dorsi was mainly used as a salvage flap. Muscle transposition provided effective heart and great vessel protection after acute hemorrhage in 18 cases. This series confirms that mortality and mean hospital stay have decreased dramatically since the routine use of muscle transposition.

Acute Disease↗
PubMed1994

Ex vivo inhibition of platelet aggregation in patients with severe limb arteriopathy treated with BAY U3405, a specific TX A2 receptor antagonist.

A double-blind, placebo-controlled randomized study with BAY U3405, a specific thromboxane A2 (TX A2) receptor blocker, was performed in patients suffering from severe stade II limb arteriopathy. BAY U3405 or placebo was administered in 16 patients at 20 mg four times a day (from day 1 to day 3). Hemostatic studies were done before therapy, and on day 2 and day 3 under therapy. On day 3, BAY U3405 was shown to induce a highly statistically significant decrease of the velocity and the intensity of the aggregations mediated by arachidonic acid (56 +/- 37% for the velocity, 58 +/- 26% for the intensity) or by U46619 endoperoxide analogue (36 +/- 35% for the velocity, 37 +/- 27% for the intensity). Similar results were already observed on day 2. By contrast, such a decrease was not noticed with ADP mediated platelet aggregation. Furthermore, plasma levels of betathromboglobulin and platelet factor 4 remained unchanged. Peripheral hemodynamic parameters were also studied. The peripheral blood flow was measured using a Doppler ultrasound; the pain free walking distance and the total walking ability distance were determined under standardized conditions on a treadmill. These last two parameters show a trend to improvement which nevertheless was not statistically significant. All together these results encourage further in vivo studies using BAY U3405 or related compounds on a long-term administration.

Adult↗
PubMed1994

["Logic" and doubts in the surgery of associated carotid and vertebral lesions].

Combined vertebral artery and carotid artery surgery may be performed in patients with proximal subclavian or vertebral artery stenosis provided that general anesthesia is not contraindicated? Others indications may be considered in patients with proved arterial thrombo-embolism or in patients for whom arteriography, cerebral angioscintigraphy and ultrasound velocimetry enable the physician to suspect a cerebral low flow and the lack of collateral pathways between the posterior and anterior cerebral system.

Carotid Artery Diseases↗
PubMed1993

Single-lung retransplantation for late graft failure.

In lung or heart-lung recipients, an irreversible graft-failure may develop in connection with chronic rejection, infection or bronchial complications. A limited number of transplant-recipients have undergone a retransplantation procedure in several centres. First results are discouraging, especially in the case of early retransplantation. We decided, 3 yrs ago, to evaluate the feasibility and benefits of single-lung retransplantation in lung-transplant recipients with late graft-failure. Eight consecutive single-lung retransplantations were performed in patients with previous single-lung (n = 7), or double-lung (n = 1) transplant. Primary graft and native lung were removed in 5 and 3 patients, respectively. The delay between the two surgical procedures was 16 +/- 10 months (range 6-37 months). Three patients died within 3 months. Long-term survivors experienced stable and satisfactory functional results (forced expiratory volume in one second (FEV1 63 +/- 21% predicted; range 40-103% predicted), with survival values ranging 8-20 months. One patient died of septic shock 16.5 months after retransplantation. The remaining four patients are alive. These data suggest that the retransplantation option could be considered in selected patients with late graft-failure. The final decision for retransplantation, however, is largely influenced by the current shortage of donor lungs.

Bronchiolitis Obliterans↗