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Biomedical subjects

G Merin

Publications and source records attributed to G Merin.

At least 37 records · Page 2Linked to original sources
PubMed1996

[Successful single-lung transplantation in emphysema].

Lung transplantation is now considered acceptable therapy for end-stage lung disease. Until recently therapy for emphysema was disappointing, but lung transplantation has brought new hope for those terminally ill with the disease. We present our early experience with single-lung transplantation in 5 men and 1 woman with emphysema, 40-61 years old. All recovered following surgery, with remarkable improvement in lung function and functional capacity. They are now 6-20 months post-transplantation, do not need oxygen supplementation and are able to perform their normal daily activities. Shortage of donor organs is the limiting factor for single-lung transplantation in these patients.

Adult↗
PubMed1996

A 31P NMR study of preconditioned isolated perfused rat heart exposed to intermittent ischemia.

Exposure to a short ischemic period (ischemic preconditioning, IP) will protect the heart from damage following a subsequent longer ischemic episode. The aim of the study was to test whether IP is cardioprotective in the setting of repeated ischemia-reperfusion cycles. Thus, Langendorff-perfused hearts, exposed to IP, were subjected to three consecutive ischemia-reperfusion (10/15 min) cycles. Myocardial energetics, manifested by 31P NMR spectroscopy, was correlated with hemodynamics. ATP recovery was significantly higher for the IP group compared with control (P < 0.02) during reperfusions. However, there was no significant difference in ATP recovery during the three ischemic intervals. The supernormal recovery of phosphocreatine recorded during reperfusion was lower for the IP group (approximately 120%) compared with control (approximately 135%, P < 0.065). Better recovery of the left ventricular-developed pressure was noted during reperfusions for the IP group and became significant only during the last reperfusion (86% versus 68%, P < 0.025). In conclusion, the above results support prolonged IP cardioprotection.

Adenosine Triphosphate↗
PubMed1996

Acute effect of thyroid hormone in the rat heart: role of calcium.

Several observations provide some clues as to the possible mode of the regulatory action of thyroid hormone (TH) in the heart, indicating delayed action at the level of the nucleus and acute effects on the plasma membrane. Here we present evidence for a direct and rapid stimulatory effect of TH in the intact normal heart. In the isolated perfused rat heart, 3,5,3'-tri-iodothyronine (T3) produced a positive inotropic effect increasing both the left ventricular peak systolic pressure (P) and +dP/dt values, but had no significant effect on heart rate. This effect of T3 was: (1) very rapid in onset (starting after 15 s) and transient, increasing gradually to reach a maximum (80% above control) at about 20 min, and declining progressively 20 to 30 min later; (2) dose-related and biphasic, occurring at physiological concentrations as low as 1 pM (+dP/dt) and 10 pM (P), reaching a maximum at 1 nM, and decreasing at higher concentrations; and (3) thyroid hormone specific, as shown by the effects of several TH analogs (L-T3 > L-thyroxine (T4) = D-T3 > D-T4; 3,3',5'-tri-iodothyronine (rT3), 3,5,-L-di-iodothyronine and DL-thyronine had no effect). The calcium blockers nifedipine and verapamil, at concentrations of 10(-8) - 10(-5) M given before or after the addition of T3 (10(-9) - 10(-6) M), inhibited the T3-induced increase in cardiac inotropic activity in a time- and dose-related fashion. We suggest that the acute effect of TH in the heart is plasma membrane-mediated and calcium-dependent.

Animals↗
PubMed1996

Early experience in lung transplantation.

Lung transplantation is becoming an acceptable mode of therapy worldwide for the end-stage lung disease. We present our initial experience with the first 10 consecutive lung transplant patients at Hadassah University Hospital. There were 5 males and 5 females with an age range 27 to 59 years. Eight patients underwent single lung transplantation, one patient had double lung transplantation and one had heart-lung transplantation. Indications were: pulmonary fibrosis in 4, emphysema in 4, cystic fibrosis in 1, and cystic bronchiectasis in 1. Two patients had primary graft failure (1 death). Nine patients had a serious infection after transplantation (1 death). Four patients developed airway complications including dehiscence of bronchial anastomosis (1 death), bronchial stenosis requiring placement of a stent in 2 patients, and pneumothorax in 1 patient. One patient required tracheostomy. One patient died of massive brain infarction secondary to pulmonary venous thrombosis and embolization. Six patients are intermediate-term survivors, with a follow-up period of 4-24 months. Four of them had at least one episode of rejection each. In all survivors pulmonary functions and quality of life improved and they do not need supplemental oxygen. We conclude that lung transplantation is a viable option for end-stage lung disease. Better selection of patients and perhaps improved immunosuppression agents will further improve outcome in lung transplantation. Shortage of donor supply is currently the limiting factor in successful lung transplantation in Israel.

Adult↗
PubMed1996

[Treatment of concomitant coronary and carotid disease].

The optimal surgical treatment for concomitant carotid and coronary artery disease is controversial. Between 1991 and 1995 we performed 34 procedures for combined disease of the carotid and coronary arteries. The first 8 operations were carotid endarterectomies followed by coronary artery bypass grafting (staged procedure). The next 26 operations were performed during a single anesthesia (combined procedure). The patients were 28 men and 6 women, aged 58-81 years (mean 68). 80% were in functional class III or IV. In 40% ventricular function was moderately or severely reduced. There was an average of 3.6 grafts per patient, and in all except 3 patients the left internal thoracic artery was used as a conduit for coronary artery bypass grafting. 30% had symptomatic carotid stenosis; there was no perioperative mortality. In the staged procedure group, 2 patients had postoperative cardiac complications: in 1 acute coronary insufficiency and acute myocardial infarction in the other. 1 had postoperative, transient, amaurosis fugax. In the combined procedure group, 1 had a myocardial infarction and 1 a minor occipital stroke. During follow-up, 1 patient died 4 months after operation of myocardial infarction, and 1 had a minor stroke. The results suggest that the combined procedure is safe and carries low risk of both mortality and morbidity. Whenever cardiac disease is stable and there is no main coronary artery disease, a staged procedure should be considered. In any other situation we continue to perform the combined procedure.

Aged↗
PubMed1995

[Endobronchial stenting in bronchial stenosis following lung transplantation].

Endobronchial stricture is not an uncommon complication following lung transplantation and may cause significant morbidity and mortality. We report our experience in a 36-year-old woman and a 39-year-old man who underwent lung transplantation and developed stenosis in the anastomotic area. Implantation of a silicone stent in 1 patient and an expandable metal stent in the other were successful. Both patients developed infections with Aspergillus fumigatus, 1 of whom died of fungal dissemination.

Adult↗
PubMed1995

Interaction of thyroid hormone and heparin in postischemic myocardial recovery.

BACKGROUND: Triiodothyronine (T3) administration can improve postischemic myocardial recovery. Heparin can interfere with cellular binding of T3. Introduction of heparin into an isolated heart model may interfere with this effect. METHODS: Four groups of 8 rat hearts were placed on a modified Langendorff apparatus. All groups underwent 15 minutes of perfusion with modified Krebs-Henseleit solution (KH), followed by 20 minutes of normothermic global ischemia and 30 minutes of reperfusion. Group I underwent reperfusion with KH. Group II underwent reperfusion with KH and 1 x 10(-6) mol/L of T3. In group III, hearts underwent preischemic perfusion with heparinized KH (1,000 U/L) and reperfusion with KH containing 1 x 10(-6) mol/L of T3 and 1,000 U/L of heparin. In group IV, rats were given heparin at 2,000 IU/kg 30 minutes before sacrifice, and isolated hearts were reperfused with KH and 1 x 10(-6) mol/L of T3. A latex balloon in the left ventricle monitored hemodynamic variables. RESULTS: Left ventricular developed pressure throughout postischemic reperfusion was greater in all the groups receiving T3 when compared with group I. Group II showed significantly greater recovery than either group III (p < 0.05) or group IV (p < 0.05). CONCLUSIONS: Addition of T3 to the reperfusate enhances postischemic myocardial recovery in the isolated heart model, whereas addition of heparin reduces this effect.

Animals↗
PubMed1995

Intraoperative detection of unsuspected distal coronary obstruction by thermal coronary angiography.

Intraoperative assessment of graft patency and completeness of revascularization can increase the success of coronary artery bypass grafting. A 56-year-old man underwent a quadruple bypass operation. Flow in the graft to the anterior descending artery was verified after completion of the distal anastomosis using a Doppler flow detector. Visualization of the native artery by thermal coronary angiography demonstrated that the flow passed into the second diagonal branch and not into the distal anterior descending artery, which had an unsuspected obstruction just distal to the anastomosis. The obstruction was dilated. Patency was verified with cold solution, and flow of warm blood to the entire artery was accomplished. This case demonstrates how the early (intraoperative) recognition of an unsuspected coronary obstruction using an infrared imaging system can improve the results of myocardial revascularization and avoid potential postoperative complications.

Coronary Angiography↗
PubMed1994

Usefulness of late potentials on the immediate postoperative signal-averaged electrocardiogram in predicting ventricular tachyarrhythmias early after isolated coronary artery bypass grafting.

The present study was undertaken to determine the value of abnormal late ventricular potentials on signal-averaged electrocardiograms (ECG) in identifying patients at risk of developing ventricular tachycardia or ventricular fibrillation in the early postoperative period after coronary artery bypass grafting. Signal-averaged ECGs were recorded immediately after operation in 72 patients. Abnormal late potentials were defined as the presence of 2 or 3 of the following: (1) root-mean-square amplitude of the last 40 ms of the QRS < 20 microV; (2) duration of the terminal QRS potentials (after 40 microV) > or = 39 ms; and (3) high-frequency QRS duration > 120 ms (in patients with conduction defects, only the first 2 criteria were used). Abnormal late ventricular potentials were present on the immediate postoperative signal-averaged ECG in 26 of the 72 patients (36%). Life-threatening ventricular tachyarrhythmias occurred in 6 patients. Late potentials were present in all 6 patients, but only in 20 of 66 (30%) who did not develop ventricular tachyarrhythmias (p < 0.005) (sensitivity 100%, specificity 70%, predictive accuracy 72%). Of 12 pre- and perioperative variables examined by univariate and multivariate regression analysis, the presence of late potentials on the signal-averaged ECG and low cardiac output postoperatively were found to be independent predictors of life-threatening tachyarrhythmias.

Action Potentials↗
PubMed1994

Open heart operation after pneumonectomy.

A coronary artery bypass operation was performed successfully on a 70-year-old patient who had undergone left pneumonectomy 40 years earlier. This case, together with a search of the literature and a mail survey among 118 cardiothoracic surgeons worldwide, yielded data on 27 such patients for review. Two patients died perioperatively. Three patients had pneumothorax, and 1 patient had recurrent pleural effusion. Difficulty in exposing the circumflex marginal branches was reported in 2 patients after left pneumonectomy. We conclude that with attention to the specific features of the preoperative, intraoperative, and postoperative management, open heart procedures can be performed on patients after pneumonectomy with acceptable operative mortality and morbidity.

Aged↗
PubMed1994

Technique for reoperative median sternotomy in the presence of a patent left internal mammary artery graft.

Damage to a patent left internal mammary artery (IMA) graft during reoperation can be catastrophic. An organized approach to reenter the mediastinum in the presence of a functioning left IMA graft is described. The sternum is opened using an oscillating saw to carefully divide the anterior and posterior tables. The right side is then dissected out first, exposing the aorta and right atrium. After placing pursestring sutures for cannulation, attention is turned to the left side. An IMA retractor is used to elevated the left edge of the sternum in incremental stages. The dissection is begun at the inferior end of the sternum, exposing the distal anastomosis first and then dissecting superiorly anterior to the IMA. A Doppler flow detector probe is used to assist in locating the artery in the adhesions.

Coronary Artery Bypass↗
PubMed1994

Warm continuous antegrade blood cardioplegia: applications in congenital heart disease.

UNLABELLED: Continuous warm blood cardioplegia is utilized by many surgeons as their method of choice for myocardial protection during operations for acquired heart disease. OBJECTIVE: this study was performed to determine the feasibility and safety of this method for intracardiac procedures through the right atrium and in particular, total cavopulmonary connection. MATERIALS AND METHODS: procedures included closure of an atrial septal defect (23), atrial septectomy (2) and total cavopulmonary connection (4). Antegrade blood cardioplegia was delivered continuously for an average of 27 +/- 21 minutes at an average flow of 130 +/- 60 cc/min to maintain the aortic root pressure between 60 and 80 mmHg (mean 74 +/- 5 mmHg). Perfusion with regular blood commenced in the last 2 to 8 minutes and complete de-airing procedure was performed on the beating heart before removal of the aortic cross-clamp. RESULTS: all patients resumed sinus rhythm and all but one had normal cardiac output postoperatively. In one patient after cavopulmonary connection the inferior vena-cava to pulmonary-artery connection was taken down because of increased pulmonary vascular resistance resulting in low output state. All patients made an uneventful recovery without neurological complications. CONCLUSIONS: this initial experience suggests that normothermic aerobic arrest can be used safely in the repair of congenital defects and may provide superior myocardial protection for complex procedures such as the Fontan procedure.

Adolescent↗
PubMed1994

Value of dobutamine/nitrate radionuclide angiography in predicting revascularization effects on ventricular function.

OBJECTIVE: Dobutamine and Nitrate Radionuclide Angiography (RNA) may help to distinguish viable from nonviable myocardium and to predict revascularization effects on LV function. SETTING: Ambulatory. EXPERIMENTAL DESIGN: Prospective. PATIENTS AND METHODS: We studied 12 patients (11 male, 1 female; mean age 56 +/- 10 years) with three-vessel disease, severe LV dysfunction, and prior MI for a mean follow-up time of 10 +/- 3.4 months. Thallium-201 scintigraphy favored potential viability in all patients: inducible ischemia with satisfactory perfusion in more than one coronary arterial territory. Global and regional LVEF's were calculated from preoperative RNA (baseline rest study and with continuous dobutamine infusion with gradual rate increase plus oral nitrates) and postoperative RNA at 1 and 6 months. RESULTS: There was no operative mortality, but two late deaths occurred. Symptomatically, most patients showed improvement. Global LVEF increased during dobutamine and nitrates preoperatively (p < 0.01), but not at 1 and 6 months postoperatively (without pharmacological intervention). Mean LVED volume was not significantly changed postoperatively. Regional EF improvement was found in 4 out of 9 LV wall segments under dobutamine and nitrates, and this increase persisted postoperatively at 1 and 6 months. CONCLUSIONS: Mild but significant increase in global LVEF during dobutamine and nitrates administration is not predictive of postoperative LVEF improvement. However, regional EF improvement appears to be predictive of post-revascularization LV functional improvement.

Administration, Sublingual↗
PubMed1993

Early IL-2/sIL-2R surge following surgery leads to temporary immune refractoriness.

High serum level of immunoreactive but not biologically active IL-2 was detected 1 day after surgery in patients undergoing major operation (abdominal, open-heart), in proportion to the tissue injury caused by surgical trauma. IL-2 values were highest in those patients who underwent open-heart surgery and received blood transfusions. In all patients they declined in the third and fourth post-operative days. Elevated serum levels of soluble IL-2 receptors (sIL-2R) were already present 1 day after operation, and peaked in the third and fifth post-operative days after mitogen triggering. Blood lymphocytes derived from operated patients secreted reduced amounts of both IL-2 and sIL-2R compared with control lymphocytes. The extent and duration of this reduction were also proportional to the tissue trauma and were affected by blood transfusions. Based on these data we suggest that early post-operative systemic immunological activation (appearance of IL-2 in the serum) is followed by elevation of sIL-2R, which then interferes with IL-2-dependent immunity. Blood lymphocytes are probably not involved in the post-operative immunological activation. The trigger for and the site of IL-2/sIL-2R synthesis are not yet clear.

Adult↗
PubMed1993

Use of the internal mammary artery for urgent myocardial revascularization.

The effect of using the internal mammary artery (IMA) as a conduit for revascularization on the outcome of early (< 30 days) coronary artery bypass graft surgery after acute myocardial infarction was determined. Forty patients were studied: 27 underwent urgent operation for ongoing ischaemia and/or haemodynamic instability early after acute myocardial infarction and 13 had emergency surgery for failed percutaneous transluminal coronary angioplasty associated with clinical and enzymatic evidence of myocardial infarction. Nine patients experienced low cardiac output before operation, in six of whom intra-aortic balloon counterpulsation was used to treat cardiogenic shock. In 26 patients (group 1) the left IMA was utilized with or without additional vein grafts. In the remainder (group 2, n = 14), only vein grafts were used. Group 1 patients were younger than those in group 2 (mean(s.d.) age 55(9) versus 67(8) years, P = 0.0001). Other preoperative and perioperative variables were similar in the two groups. There was one death in hospital (2%, group 2). Eight (31%) group 1 patients sustained postoperative low cardiac output compared with ten (71%) in group 2 (P < 0.04). Preoperative low cardiac output (P < 0.025) and non-use of the IMA (P < 0.05) were identified by univariate and multivariate analysis as the most significant independent predictors of low cardiac output after operation. Although age was excluded as a predictor of low cardiac output, it is concluded that the IMA is an adequate conduit that can safely be used in patients younger than 70 years of age undergoing myocardial revascularization during or early after acute myocardial infarction.

Adult↗
PubMed1992

Serum levels of IL-1, IL-6 and tumour necrosis factors in patients undergoing coronary artery bypass grafts or cholecystectomy.

Plasma levels of biologically active IL-1, tumour necrosis factor (TNF) and IL-6 were measured before, during and after coronary artery bypass graftings (CABG) (n = 9) and cholecystectomy (CHO, n = 9), and in normal controls (nine healthy volunteers). Mean pre-operative IL-1 concentration in four of the nine CABG patients was 0.452 + 0.03 ng/ml, significantly (P less than 0.001) higher than that of the other five (0.045 +/- 0.009 ng/ml), CHO patients (0.035 +/- 0.005 ng/ml) and controls (0.029 +/- 0.008 ng/ml). Three of the four patients with high pre-operative IL-1 had functional capacity IV, while the other five had functional capacity IIa or IIb. Slight IL-1 elevation after anaesthesia, followed by reduction after initiation of bypass, elevation on completion of surgery and reduction to basal levels after 7 days was found in patients undergoing CABG. Mean basal TNF levels of CABG and CHO patients did not differ, but were higher than those of controls (2.85 +/- 0.5 ng/ml for CABG, 2.05 +/- 0.06 ng/ml for CHO, 0.72 +/- 0.07 ng/ml for normals, P less than 0.001). A unique kinetics of release during CABG was observed also for TNF. Mean pre-operative IL-6 levels were normal (50 +/- 3 ng/ml for CABG, 50 +/- 0.5 ng/ml for CHO and 65 +/- 10 ng/ml for controls). Gradual elevation to a mean peak of 725 +/- 100 ng/ml on completion of CABG was observed as compared with 275 +/- 50 ng/ml in CHO (P less than 0.01). On the seventh post-operative day mean IL-6 levels returned to normal. Two patients with post-operative low-grade fever (38 degrees C) had high, late cytokine levels. One of these two patients had leucocytosis, sterile discharge from the operative wound and was diagnosed as suffering from the Dressler syndrome. In this study elevated cytokine values and unique kinetics of release into the serum were found in patients undergoing CABG.

Adult↗
PubMed1991

[Early revascularization after acute myocardial infarction].

Coronary artery bypass grafting (CABG) was performed on 40 consecutive patients within the first month after acute myocardial infarction (AMI) between January 1985 and July 1988. Group I (N = 27) included patients with unstable postinfarction angina who underwent operation within 16 +/- 14 days after infarction. Group II (N = 13) underwent emergency operation after failed percutaneous transluminal coronary angioplasty (PTCA) which was complicated by AMI. This group was operated on within 4.5 +/- 3 hours after onset of symptoms. There was left ventricular dysfunction (ejection fraction less than .35) in 8 Group I patients. Ventricular function of Group II patients during and after infarction could not be evaluated. The internal thoracic (mammary) artery (ITA) was used in 26 patients. Early mortality was 2.5% (1 patient). Preoperative low cardiac output (LCO) was associated with increased need for inotropic and intra-aortic balloon pump support during termination of cardiopulmonary bypass (p less than 0.02), and it predicted postoperative LCO (p less than 0.03). Preoperative reduced ventricular function was associated with increased need for inotropic support, LCO, and ventricular arrhythmias (p less than 0.02, p less than 0.05, p less than 0.02, respectively). The postoperative course was complicated by LCO in 71% of those with saphenous vein grafts, but in only 30% of those with ITA grafts (p less than 0.02). Inotropic and mechanical support needed during weaning from cardiopulmonary bypass was significantly less in those with the ITA graft (p less than 0.05, p less than 0.03, respectively). Hospital stay after surgery was 12 +/- 7 and 9 +/- 2 days for Groups I and II, respectively (NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗