Endothelial function of human gastroepiploic artery in comparison with saphenous vein.

OBJECTIVE: Endothelial function is one of the important determinants of patency rate of a graft material used in coronary revascularisation. The aim of this study was to compare the endothelial reactivity of human gastroepiploic artery versus saphenous vein in response to various vasoactive substances. METHODS: Gastroepiploic artery and saphenous vein rings were mounted in an organ bath containing Krebs-Ringer bicarbonate solution aerated with 95% O2 and 5% CO2 at 37 degrees C. Endothelium dependent responses of acetylcholine, histamine, and bradykinin were examined on the precontracted rings of the vessels. The sensitivity of these two graft materials to the potent vasoconstrictor agent endothelin-1 was also compared. RESULTS: Acetylcholine, histamine, and bradykinin caused dose dependent relaxations in saphenous vein and gastroepiploic artery rings. These agonists were more effective in producing endothelium dependent relaxations in the artery than in the vein. Endothelium removal and pretreatment with nitro-arginine abolished the relaxations completely in saphenous vein but not in gastroepiploic artery, depending on the relaxing agent used. On the other hand, both graft materials showed nearly equal sensitivity to endothelin-1 (EC50 values; 3.5 x 10(-9) M in the vein versus 6.4 x 10(-9) M in the artery, p = NS) which was not affected by endothelium removal. CONCLUSIONS: Gastroepiploic artery exhibited more pronounced relaxation and a different response profile to endogenous vasoactive substances than saphenous vein. The demonstration of higher capacity of the artery to release vasoactive substances in response to various endogenous agents shows that gastroepiploic artery may have a better long term patency rate than saphenous vein.

Cardioplegia with adenosine and adenosine triphosphate in the isolated guinea pig heart.

In order to determine the effect of adenosine triphosphate (ATP) and adenosine in cardioplegic solutions, a comparative study has been undertaken in isolated guinea pig hearts using the Langendorff perfusion technique as a model of cardiopulmonary bypass. The hearts (n = 10 in each group) previously being perfused by Krebs-Henseleit solution, were arrested by one of the following cardioplegic solutions: 1) Potassium 20 mM/L (Plegisol), 2) Potassium 20 mM/L+ATP 10 mM/L, 3) Adenosine 10 mM/L, 4) Adenosine 10 mM/L+ATP 10 mM/L. After 45 min of hypothermic ischemia, postischemic recovery of heart rate, ventricular contractility, heart work and postischemic changes in tissue enzymes (LDH, SGOT, SGPT) were compared among the 4 different cardioplegic solutions. Arrest time and number of arrest beats were also recorded and compared among the groups. Although similar beneficial results on postischemic recovery were achieved with adenosine cardioplegia and with ATP supplemented potassium cardioplegia, ATP supplemented adenosine cardioplegia did not show any beneficial effects on postischemic recovery.

Effect of ATP and verapamil as cardioplegic additives in the isolated guinea pig heart.

1. A comparative study on isolated guinea pig hearts was carried out to determine the effects of ATP and verapamil as cardioplegic additives. 2. The hearts were arrested by one of the plegic solutions: I, potassium 20 mmol/l; II, potassium 20 mmol/l+verapamil 1.1 mumol/l; III, potassium 20 mmol/l+ATP 10 mmol/l. After 45 min of hypothermic ischemia, the hearts were reperfused by Krebs-Henseleit buffer. 3. Postischemic percentage change of myocardial functions (heart rate, contractility, heart work) and tissue enzymes (LDH, SGOT, SGPT) were compared between the groups. 4. Although a rapid cardiac arrest could be obtained by verapamil added cardioplegia. Postischemic myocardial recovery was much better with ATP added cardioplegic solutions.

Protamine releases endothelium-derived relaxing factor from systemic arteries. A possible mechanism of hypotension during heparin neutralization.

BACKGROUND: When used to reverse the anticoagulant effect of heparin, protamine sulfate often causes vasodilation that can lead to systemic hypotension. Protamine is rich in the basic amino acid arginine, which is the precursor of endothelial cell synthesis of nitric oxide, and nitric oxide is the active component of endothelium-derived relaxing factor (EDRF). METHODS AND RESULTS: To determine whether the hypotensive effect of protamine could be due to stimulated release of EDRF, we studied rings (4-5 mm) of canine coronary, femoral, and renal artery suspended in organ chambers containing physiological salt solution (37 degrees C and 95% O2-5% CO2). Arterial rings with and without endothelium were contracted with prostaglandin F2 alpha (2 x 10(-6) M) and exposed to increasing concentrations of protamine (final organ bath concentration, 40-400 micrograms/ml). In arterial segments without endothelium, protamine caused only a modest decrease in tension. However, protamine induced concentration-dependent relaxation in all arterial segments with endothelium, which was significantly greater than in segments without endothelium (p less than 0.05). The endothelium-dependent relaxation induced by protamine was inhibited by NG-monomethyl-L-arginine (L-NMMA) (10(-5) M), but L-NMMA had no effect on rings without endothelium. The action of L-NMMA could be reversed by L-arginine (10(-4) M) but not D-arginine (10(-4) M). CONCLUSIONS: This study demonstrates that protamine stimulates the release of EDRF from arterial endothelium, and that endothelium-dependent vasodilation may be an important cause of systemic hypotension during protamine infusion.

Comparison of potassium and adenosine cardioplegia with or without verapamil in the isolated guinea pig heart.

1. The cardioprotective effects of adenosine cardioplegia and classical potassium cardioplegia with or without adding verapamil were investigated in isolated guinea pig heart. 2. Four different cardioplegic solutions were used to arrest the hearts which were previously perfused by Krebbs-Henseleit solution. (A) potassium 20 mMol/l. (B) Potassium 20 mMol/l + verapamil 1 micromol/l. (C) Adenosine 10 mMol/l. (D) Adenosine 10 mMol/l + verapamil 1 microgram/l. 3. Both of the adenosine-containing solutions shortened the arrest time and maintained better postischemic recovery according to the potassium cardioplegia. 4. A rapid cardiac arrest was observed when verapamil was added to cardioplegic solutions, on the contrary there was no significant effect on postischemic recovery.

An unusual late complication following surgical repair of tetralogy of Fallot.

A case is presented of extrusion of right ventricular outflow tract patch material through a mediastino-cutaneous fistula occurring five years after repair of tetralogy of Fallot. The focus of the mediastinal infection was an infected epicardial pacemaker electrode placed at the time of initial surgery. Subsequent echocardiographic studies showed minimal right ventricular outflow tract or pulmonary arterial dilatation, and, with no further surgery, the child is well after two and a half years follow-up.

Surgical treatment of bronchiectasis: a collective review of 487 cases.

Pulmonary resection to treat bronchiectasis in a total of 487 patients between December 1976 through June 1988 is reported on. The surgical treatment consisted of pneumonectomy in 190 cases (144 left and 46 right), lobectomy in 202 cases, bilobectomy in 23 cases and lobectomy combined with segmental resection in 72 cases. The overall mortality rate was 3.5%. Patients were followed up for a period ranging between 4 months to 10 years: at the end of the study 71% of the patients were completely asymptomatic. It is concluded that though the first choice of therapy must be conservative, in those patients with bronchiectasis in whom disease progresses despite medical treatment and in those whose disease requires frequent hospitalization, continuing medical treatment is unwarranted and surgery must be the choice of therapy.

Primary mediastinal liposarcoma. A report of a case and review of the literature.

A case of primary liposarcoma of the mediastinum with a review of the literature is presented. Liposarcomas may attain a large mass and exhibit various kinds of clinical symptoms according to their localisation. Histological typing is very important in determining the type and extent of therapy. Surgical excision of the tumour is the therapy of choice in all cases. Radiotherapy may be of value for the palliation of unresectable cases.