The interstitial fluid of the human myocardium was monitored in 13 patients undergoing aortic valve and/or bypass surgery before, during, and after hypothermic potassium cardioplegia. The regulation of glucose and lactate was studied after sampling with microdialysis. The following questions were addressed. 1) Is the rate of transcapillary diffusion the limiting step for myocardial uptake of glucose before or after cardioplegia? 2) Does cold potassium cardioplegia induce a critical deprivation of glucose and/or accumulation of lactate in the myocardium? Before cardioplegia, interstitial glucose was ∼50% of the plasma level ( P < 0.001). Interstitial glucose decreased significantly immediately after induction of cardioplegia and remained low (1.25 ± 0.25 mM) throughout cardioplegia. It was restored to precardioplegic levels 1 h after release of the aortic clamp. Interstitial glucose then decreased again at 25 and 35 h postoperatively to the levels observed during cardioplegia. Interstitial lactate decreased immediately after induction of cardioplegia but returned to basal level during the clamping period. At 25 and 35 h, interstitial lactate was significantly lower than before and during cardioplegia. Glucose transport over the capillary endothelium is considered rate limiting for its uptake in the working heart but not during cold potassium cardioplegia despite the glucose deprivation following perfusion of glucose-free cardioplegic solution. Lactate accumulated during cardioplegia but never reached exceedingly high interstitial levels. We conclude that microdialysis provides information that may be relevant for myocardial protection during open-heart surgery.

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Antibodies to BiP are found in the sera of patients with RA and in sera antedating the onset of RA.

Un ive rsity of Go thenburg. Go thenbu rg, Swe de n Summary Ten cons ec ut ive pa tien ts aged 2 5 to 75 with po stoperat ive emp yema or hemothorax co nven tionally t reated with drainage w itho ut sufficient effe ct wer e given int rapleural lnst ltlations of st rep t ok inase (K ab iki nase® , 250 .00 0 IE ) f or 4 hou rs!) . Th e eff ects on systemic fibrin oly sis were st ud ied .Venous bl ood samp les for dete rm inati on o f f ib ri noly ti c activity on fibrin plate s, plasmin ogen , Qrant iplasmin. Cl'r macroglob ulin, fibrin ogen , fib rin toqen } degrada tio n product s (FOP) and thrombin t ime were taken befo re inst illat ion, after inst illat ion and th en after 24 hour s. Preinatillation values were co mpa red to the values 4 and 24 hour s afte r instillat ion with Student 's paired t-te st . There ware no differen ces in fibrin olyti c activit y, Ct2-macroglo bulin and thrombi n time . There was a slight increase in plasminog en, Q2-antiplasmin and fibrinogen , probably due to an acute phas e react ion . Fibrin degradati on produ cts showed an increase with borde r line significance. These changes are not consisten t with genera lized fibrin olysis, and it is concluded that int rapleural instil lation s of st rept oki nase can be given safely in the early postt raumat ic or posto perative per iod . Key-Words: Fibrinolysis -Pleur a eff usion -Streptokin ase Int roductionIntrapleural instillations of strep tokinase and fibrinolytic enzyme s have been used for more than 30 years in treating patients with intrathoracic fluid, such as empyema or hemoth orax, not responding to conventional treatment with anti biotic s (I , 6 , 7, 10, 1I) . Streptokinase is a p rotein which acts by transforming plasminogen to plasmin , which in tum splits fibrin ogen and, in particular, fibrin . After an intravenous injection of strep tokinase plasma plasminogen decreases due to consumption . The plasmin fonned bind s to a, -antipl asrnin and a, -macroglobulin, which likewise decrease. Part of the plasmin also binds to fibrin and starts the degradation pro cess. Fibrin degradation products are formed and can be estimated in blood by thrombin time measurements and immunological methods. Successful intravenous st rep tokinase tre atment should therefore produce low plasma concentrations of pla sminogen, a,-antiplasmin, a, -macroglobulin and fibrinog en, and high concent ratio ns of fibrinogen degradation p rodu ct s, and at the same time any intravenou s fibrin is dissolved . 1) Kabi AB, Stoc kho lm, Sweden

This study aims at developing per- and postopertive surveillance of the myocardium and focuses on ischemic damage following cardioplegic heart arrest. Levels of troponin T and total aspartate aminotransferase (ASAT) were analyzed in the myocardial interstitium of 10 patients with ischemic heart disease (IHD) who underwent coronary bypass surgery and in 12 patients with nonischemic heart disease (N-IHD) who underwent valvular surgery. Fluid from the myocardial interstitium of the anterior and the lateral wall of the heart was sampled by microdialysis probes that were implanted during surgery and extracted percutaneously 70–100 h later. There were no adverse reactions, and the equipment did not interfere with the surgical procedures. The peak in troponin T serum levels that occurred 4 h after cardiac arrest was preceded by a peak in troponin T levels in the microdialysates from the interstitium that occurred 1 h earlier. The concentration of troponin T in the microdialysate peak was 300 times higher than in the serum peak. The increase in serum ASAT levels during the first 7 h after cardiac arrest corresponded in time with a decrease in interstitial ASAT levels, which had already reached a maximum during cardiac arrest. The microdialysate/serum concentration ratio was considerably smaller for ASAT than for troponin T. Interstitial peak levels of troponin T correlated positively and significantly with peak levels of ASAT. Of the 22 patients, 15 had no postoperative events according to clinical outcome, ECG and serum tests. Fourteen of these had low to normal levels of interstitial ASAT and troponin T. Conversely, atrial fibrillation and/or premature atrial contractions were recorded in 8/22 patients, 7 of whom had elevated interstitial ASAT and/or troponin T concentrations in one or both of the sampled heart regions. The N-IHD patients had higher levels of troponin T in the interstitium 20–70 h following cardioplegia, while the peak levels did not differ between the groups. In conclusion, microdialysis sampling of troponin T and ASAT is safe and allows a highly sensitive analysis of the ischemic trauma exerted by the cardioplegic arrest.