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Biomedical subjects

M Pasic

Publications and source records attributed to M Pasic.

At least 55 records · Page 3Linked to original sources
PubMed1995

The reaction of Helix photosensitive neurons to light and cyclic GMP.

The effect of light and cyclic nucleotides (cGMP and cAMP) on a group of identified photosensitive neurons in Helix pomatia left parietal ganglion was examined. The onset of light induces in these cells a slow inward current shift associated with decrement of slope conductance. The reversal potential (Erev) of the light induced current (IL) and its changes due to altered extracellular concentration of potassium support the assumption that (IL) is due to suppression of K+ conductance. Elevation of intracellular concentration of cyclic GMP by adding 8-bromo-cGMP into the bathing solution or by injecting the nucleotide into the cell mimics, in all cases, the effect of light: it produces an inward current accompanied by decrement of slope conductance. The effect of elevation of cAMP was inconsistent. The I-V relations of IL and IcGMP follow a similar course and have a common Erev. The assumption that 3',5'-cyclic GMP is increased by light is also supported by comparing the effect of light and the cyclic nucleotide on the action potential. Both light and 8-bromo-cGMP broaden the action potential by increasing the voltage-dependent Ca2+ current.

Animals↗
PubMed1995

The influence of leukocyte filtration during cardiopulmonary bypass on postoperative lung function. A clinical study.

The accumulation of activated leukocytes in the pulmonary circulation plays an important role in the pathogenesis of lung dysfunction associated with cardiopulmonary bypass. Animal studies have demonstrated that the elimination of leukocytes from the circulation reduces postoperative lung injury and improves postoperative pulmonary function. We conducted a prospective randomized clinical study to evaluate whether postoperative lung function could be improved by use of a leukocyte filter during cardiopulmonary bypass. Elective coronary artery bypass grafting was done with a leukocyte-depleting arterial blood filter incorporated in the extracorporeal circuit (14 patients, leukocyte filter group) or without the filter (18 patients, control group). Blood samples collected at intervals before, during, and after operation were used for analysis of blood cell counts, elastase concentrations, and arterial blood gases. The use of the leukocyte filter caused no significant reduction in leukocyte count (p = 0.86). There were no differences in postoperative lung function between the groups, as assessed through (1) oxygenation index (290 for leukocyte filter group compared with 329 for control group, 95% confidence interval, 286 to 372, p = 0.21), (2) pulmonary vascular resistance (p = 0.10), and (3) intubation time (16.6 hours for leukocyte filter group versus 15.7 hours for control group, 95% confidence interval, 12.1 to 19.1 hours, p = 0.72). The levels of neutrophil elastase were significantly higher at the end of cardiopulmonary bypass in the leukocyte filter group (460 microgram/L in leukocyte filter group versus 230 microgram/L in control group, 95% confidence interval, 101 to 359 microgram/L, p = 0.003). We conclude that the clinical use of the present form of leukocyte-depleting filter did not improve any of the postoperative lung function parameters analyzed in this study.

Cardiopulmonary Bypass↗
PubMed1995

Aneurysm of the superior mediastinal veins.

A case of true venous aneurysm with saccular dilation of the proximal half of the superior vena cava, the right innominate vein, and the distal two thirds of the left innominate vein in an 18-year-old white woman is presented. At surgery part of the aneurysmal wall was resected, and subsequently the mediastinal venous system was reconstructed with use of the rest of the aneurysmal wall. The postoperative course was uneventful. Operative treatment of mediastinal venous aneurysms is indicated to prevent possible major complications. We strongly suggest performance of this surgery only by means of a heart-lung machine.

Adolescent↗
PubMed1995

Modified operation technique for orthotopic heart transplantation.

Atrioventricular (AV) valve dysfunction with tricuspid regurgitation is a common finding after orthotopic heart transplantation (HTx). In 20 patients the heart transplantation was performed with bicaval anastomoses and the results were compared to the precedent 20 patients operated with the standard technique. The right atrium of the recipient was completely removed and the caval anastomoses were performed on the beating heart during reperfusion. Using an interrupted suture line, no stenoses at the venous anastomoses were seen as known from the early implantation technique in heart-lung transplantation. Due to a more stable sinus rhythm only 15% of the patients in the bicaval group needed prolonged pacing (> 30 min) versus 55% (P < 0.01) in the group with standard operation. One to 3 months after surgery the transthoracic echocardiographic evaluation of the AV valve function showed tricuspid valve regurgitation (TVR) in 20% of the patients with bicaval anastomoses versus 75% with a right atrial anastomosis (P < 0.001). Tricuspid valve regurgitation during the first 2 weeks (in 31% of recipients with bicaval and in 70% with atrial anastomoses) improved in all recipients with bicaval anastomoses and in 14% of the recipients with atrial anastomosis. The modification of the operation technique did not result in significantly longer bypass time (75 +/- 14 versus 68 +/- 14 min) and ischemia time (44 +/- 12 versus 41 +/- 9 min with local organ procurement and 111 +/- 24 versus 101 +/- 19 min with distant organ procurement). The AV valve function and the postoperative rhythm after orthotopic HTx can be improved by implanting the heart with bicaval anastomoses.

Adult↗
PubMed1995

Outflow tract obstruction after mitral valve repair without an annuloplasty ring.

We report that systolic anterior motion of the mitral valve with significant left ventricular outflow tract obstruction can occur after mitral valve reconstruction without using an annuloplasty ring. A 69-year-old male patient with mitral regurgitation and ischemic heart disease underwent combined mitral valve reconstruction without an annuloplasty ring, and coronary artery bypass grafting. Intraoperative transesophageal echocardiography performed at the end of the operation revealed systolic anterior motion of the mitral valve with significant outflow tract obstruction requiring a second pump run with return to cardiopulmonary bypass and additional mitral valve replacement during the same thoracotomy.

Aged↗
PubMed1995

Cryopreserved arterial homografts for in situ reconstruction of mycotic aneurysms and prosthetic graft infection.

The management of mycotic aneurysms and prosthetic graft infection of major thoracic and abdominal vessels and infected extra-anatomic bypass remains a problem in vascular surgery. Cryopreserved arterial homografts, being resistant to infection, offer hope for in situ vascular reconstruction in the presence of an infection. We analyzed clinical, microbiological, preoperative and postoperative magnetic resonance imaging (MRI), computed tomography (CT), echocardiography and/or angiography data in 12 patients with mycotic aneurysm or prosthetic graft infection, in whom cryopreserved arterial homografts were used to replace infected segments of major thoracic and abdominal vessels. The hospital mortality was 8.3%. The average postoperative hospital stay was 18 +/- 14.5 days (6 to 45); antibiotic treatment was continued for 31 +/- 12 days (4 to 42). During the mean follow-up time of 18.6 +/- 12.8 months (2 to 48) two patients died, but only one (9%) was homograft-related. Recurrence of infection, suture line problems or homograft stenosis or aneurysm were not observed. Therefore, in situ replacement with cryopreserved arterial homografts is an effective treatment for mycotic aneurysms and graft infection of thoracic aorta, abdominal aortic/iliac vessels and infected extra-anatomic bypass. This operative technique has a low early and late mortality, obviates the need for complex extra-anatomic reconstruction, allows safe in situ repair, reduces postoperative antibiotic requirements, shortens the hospital stay and renders early or medium-term reoperations unnecessary.

Adult↗
PubMed1994

[Extra-anatomic thoraco-bifemoral bypass: an excellent alternative to in-situ reconstruction for repeat revascularization of the lower limbs].

Severe late complications after reconstruction of the abdominal aorta are unusual; when they occur, they demand a different strategy to treat the patient with success and to achieve a durably favourable long term outcome. These complications include prosthetic infection, enteric erosion and graft thrombosis. Treatment by resection of the infected graft and extra-anatomic reconstruction with axillary-femoral or axillary-popliteal bypass leaves the patient with an unreliable arterial inflow for the lower extremities. In patients who survived graft removal and extra-anatomic bypass, a source of major arterial inflow should be at least considered in order to secure a permanent repair. The descending thoracic aorta has been described as an ideal inflow source for definitive intracavitary conversion of extra-anatomic subcutaneous bypass and as a valid alternative to avoid dense adhesions in the abdomen or retroperitoneum. We present our experience with 8 patients in whom the aorta had been previously oversewn below the renal arteries (resection of infected graft [n = 4], repair of aorto-enteric fistula [n = 3]) or avoided because of dense adhesions after radiotherapy (n = 1). Temporary extra-anatomic reconstruction consists of an axillo-femoral (-popliteal) bypass on the right side with femoro-femoral cross-over graft. This method avoids surgery in the left thoraco-abdominal region, thus facilitating the definitive repair. Proper preoperative radiographic evaluation with inflow and outflow details is essential before conversion into thoraco-bifemoral bypass. Posterolateral thoracotomy is performed and the chest entered in the 7th interspace. The thoracic aorta is clamped tangentially and a bifurcated graft is anastomosed to the aorta. The bypass is passed through a retroperitoneal tunnel and anastomosed end-to-end with the distal portion of the previously inserted grafts; this technique avoids a second dissection of the vessel itself.(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta, Abdominal↗
PubMed1994

[Dynamic obstruction of the left ventricular outflow tract: surgical problems].

Dynamic subaortic obstruction caused by septal hypertrophy may worsen the hemodynamics in some patients after heart surgery. Resection of the hypertrophied septum allows normal left ventricular function. We describe two patients with subaortic stenosis and a complicated postoperative course following heart surgery and additional resection of the subaortic muscular stenosis. One patient was reoperated because of residual obstruction of the left ventricular outflow tract; the postoperative course was uneventful thereafter. The second patient died after the primary surgery because of low output syndrome and sepsis. The postoperative management of this group of patients is difficult, demanding frequent assessment of the patient's hemodynamic condition and echocardiographic surveillance.

Aged↗
PubMed1994

[Cardiovascular interventions in elderly patients].

From January 1981 to December 1990, 204 patients between 70 and 81 years of age underwent aortocoronary bypass-surgery, and 20 patients age 80 years or older underwent valvular surgery. The operative mortality rate (30-day mortality) of aortocoronary bypass-surgery was 6.8%; actuarial survival rate at 1 and 5 years was 92% and 86%, respectively. The operative mortality rate of valvular surgery was 15%; actuarial survival rate at 1 and 5 years was 78.5% and 67%, respectively. The mean follow-up was 25 months. Most patients undergoing myocardial revascularization (71%) and all the patients undergoing valvular surgery were preoperatively in New York Heart Association (NYHA) functional class III or IV, at the end of the follow-up in NYHA functional class I or II (95%). A rapid rise in the number of heart operations in the elderly is evident. It is associated with increased but acceptable operative risk. Longterm results and postoperative improvement of functional status are satisfactory.

Age Factors↗
PubMed1994

[Problems and results of coronary reoperation].

Reoperative coronary bypass surgery has been encountered with increasing frequency over the last few years. It is associated with several major problems: difficulties with myocardial protection secondary to progression of arterial disease and occluded saphenous vein grafts, left ventricular dysfunction, and concomitant medical and vascular disease. We present our experience with 194 consecutive patients operated on between 1980 and 1992. They represent 4.0% of the overall number of isolated coronary revascularizations performed during the same period. There were 178 men and 16 women, mean age 58.6 +/- 7.4 years. The interval between primary coronary bypass grafting operation and redo-operation extended from 4 to 12 years, mean 8.2 years. At reoperation, 91.7% (178/194) of the patients received at least one arterial conduit, whereas revascularization with arterial conduits only was performed in 16 patients. Perioperative mortality amounted to 4.6% and was significantly higher than mortality of primary isolated coronary operations (1.6%) during the same period; the following significant morbidity was encountered: perioperative myocardial infarction (8.2%), postoperative low output requiring intraaortic counterpulsation (8.7%), postoperative bleeding (8.2%) and infectious complications (9.2%). First postoperative follow-up showed a significant improvement of symptomatology with a decrease of 1.5 point in NYHA functional class. Mid term survival is promising with a 5-year survival rate of 88.5%. Improved myocardial preservation and a trend towards complete revascularization should become routine and will probably reduce perioperative mortality and morbidity.

Adult↗
PubMed1994

Amaurosis fugax.

Explore the source record for details and available documents.

Adult↗
PubMed1994

Superior late patency of small-diameter Dacron grafts seeded with omental microvascular cells: an experimental study.

The purpose of the study was to investigate the effect of omental microvascular cell seeding on the patency of small-diameter Dacron prostheses usable for coronary artery bypass grafting. In a canine carotid artery model, each dog (n = 64) received one seeded and one similar nonseeded Dacron prosthesis (internal diameter = 4 or 6 mm). Enzymatically harvested omental microvascular cells (omentum = 27.6 +/- 5.9 g [+/- the standard deviation]; range, 17 to 50 g) were seeded prior to implantation. The seeding density was 1.91 +/- 0.26 [+/- the standard error] x 10(6) cells/cm2 of graft surface. Dipyridamole (75 mg/d) and acetylsalicylic acid (325 mg/d) were administered orally for 4 weeks postoperatively. The prostheses were explanted between 2 and 52 weeks after placement. The results were assessed by angiography; light, scanning electron, and transmission electron microscopy; and morphometry. The seeded grafts developed a uniform luminal monolayer of endothelial cells with minimal platelet or cellular deposition. These grafts also had a significantly higher overall patency rate and significantly larger thrombus-free surface areas than the nonseeded grafts. The overall actuarial patency rates at 1 week, 5, 12, 26, and 52 weeks were 100%, 98%, 93%, 93%, and 93%, respectively, for seeded Dacron grafts and 100%, 91%, 61%, 54%, and 18%, respectively, for nonseeded grafts. The patency rates of Dacron grafts usable for coronary artery bypass grafting are significantly improved by seeding with omental microvascular cells in a canine model.

Actuarial Analysis↗
PubMed1994

Aortic homograft and mitral valve repair in a patient with Werner's syndrome.

We report the case of a 66-year-old man suffering from Werner's syndrome (adult progeria); he presented with several cardiac disorders, including coronary artery disease, aortic stenosis, and mitral regurgitation, mainly due to calcific deposits in the mitral annulus and the aortic cusps. Treatment consisted of mitral repair, homograft replacement of the aortic valve, and coronary artery bypass grafting. Avoidance of prosthetic material because of chronic infectious skin ulcers constituted the main goal of the operation.

Aged↗
PubMed1994

Risk and benefit of low systemic heparinization during open heart operations.

Heparin surface-coated perfusion equipment with improved thromboresistance was evaluated in 104 consecutive patients undergoing open heart operation in a prospective, randomized trial with low versus full systemic heparinization. Surgical procedures included coronary artery revascularization in 47 of 54 (87%) for low versus 44 of 50 patients (88%; not significant [NS]) for full, valve repair/replacement in 8 of 54 (15%) for low versus 5 of 50 patients (10%; NS) for full, left ventricular aneurysm repair in 1 of 54 (2%) for low versus 2 of 50 patients (4%; NS) for full, and other in 3 of 54 (6%) for low versus 3 of 50 patients (6%; NS) for full. Cross-clamp time was 39.2 +/- 10.7 minutes for low versus 39.5 +/- 10.5 minutes for full (NS). Cardiopulmonary bypass time was 68.6 +/- 20.1 minutes for low versus 69.3 +/- 16.6 minutes for full (NS). Lowest activated coagulation time during perfusion was 255 +/- 75 seconds for low versus 537 +/- 205 seconds for full (p < 0.0005). In the low group, the target activated coagulation time of more than 180 seconds was not reached during perfusion in 4 of 54 patients (7%), the lowest value being 164 seconds. No oxygenator failure occurred. Hospital mortality was 0 of 54 (0%) for low versus 1 of 50 patients (2%) for full (NS). Bleeding required surgical revision in 0 of 54 (0%) for low versus 4 of 50 patients (8%) for full (p = 0.05). Drainage (24 hours) was 790 +/- 393 mL for low versus 1,039 +/- 732 mL for full (p < 0.025).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Coagulation↗
PubMed1994

Should cardiac transplantation for congenital heart disease be delayed until adult age?

The number of pediatric heart transplantations for complex congenital heart disease has increased over the last years, but little experience has been reported in adolescent and adult populations. Between 1987 and 1992, 14 patients (mean age 33.2 years, range 14 to 51 years) were transplanted in our institution because of structural congenital heart disease (n = 9) or other rare disorders of the endomyocardial morphogenesis (n = 5). The main diagnosis included transposition of the great arteries, congenitally corrected transposition of the great vessels, left superior vena cava, tricuspid atresia with right ventricular hypoplasia, double outlet right ventricle with transposition, left ventricular sinusoidal malformation and right ventricular dysplasia. In several cases there were additional intracardiac malformations, including ventricular septum defect, atrial septum defect as well as different forms of pulmonary stenosis. Seven patients had undergone one or more palliative repairs that consisted of modified Blalock-Taussig shunts, Glenn's cavopulmonary anastomosis, Waterstone shunt, Blalock-Hanlon atrioseptectomy and Brock pulmonary valvotomy. Two patients had undergone Senning procedure for transposition of the great arteries. The donor cardiectomy was modified in order to include complete inflow and outflow tissue in the explant and transplantation could be performed without prosthetic material in all patients; deep hypothermic cardiac arrest was never necessary in this series. There was no early or late mortality after a mean follow-up of 37 months (range 4 to 74 months); postoperative echocardiography and cardiac catheterization demonstrated perfect anatomical and functional results in all patients. Adolescent and adult patients with complex congenital cardiac diseases can be transplanted with a very low perioperative risk, even after several prior operative procedures.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗