Plasma fibrinopeptide A (FPA), fibrinopeptide B β 15-42 (FPB β 15-42), and fibrin/fibrinogen degradation products (FDP) were measured before treatment for the determination of the diagnostic value of ...coagulation and fibrinolytic molecular markers in patients with pulmonary thromboembolism (n=16) and myocardial infarction (n=8). The levels of all markers measured prior to treatment were significantly higher in patients with pulmonaly thromboembolism than those in the patients with acute myocardial infarction, irrespective of shock (FPA, 40.0±22.1vs. 17.9±24.8ng·ml-1, p=0.0085; FBP β 15-42, 34.1±20.8vs. 12.8±8.7ng·ml-1, p=0.0044; FDP, 37.5±36.7vs. 6.3±6.5μg·ml-1, p=0.0022). All of the markers had high sensitivity, specificity and predictive values for the diagnosis of pulmonary thromboembolism when the cut off points of FPA, FPB β 15-42 and FDP were set at 20ng·ml-1, 15ng·ml-1 and 10μg·ml-1, respectively. We concluded that: 1) the markers measured in this study are all useful for the differential diagnosis of pulmonaly thromboembolism and acute myocardial infarction, and 2) pulmonaly thromboembolism is the most likely diagnosis when any of the following is positive: FPA>20ng·ml-1, FPB β 15-42>15ng·ml-1 or FDP>10μg·ml-1.
In septic ICU patients, cardiac function is depressed in the progress of septic shock. We examined to determine whether the depressed cardiac function in septic shock is associated with alterations ...in the β-adrenoceptor signal transduction system in myocardium. Male New Zealand White rabbits (2-2.2 kg) received a single ear-vein injection of 100 μg/kg lipopolysaccharide (LPS). LPS produced a gradual decrease in arterial blood pressure, which reached a nadir by 6 h. In isolated papillary muscles, the concentration-response curves for the positive inotropic response to isoproterenol were significantly shifted to the right 3 and 6 h after LPS. The maximum response was significantly reduced at 6 h. The diminished inotropic response to isoproterenol was not reversed by N^G -nitoro-L-arginine The positive inotropic effects of NKH 477 and dibutylic cyclic AMP were unaltered by LPS. Radioligand binding experiments with ^^125 I-iodocyanopindolol showed no significant defferences in the β-adrenoceptor density and dissociation constant between myocardial membranes from control and those from 3 and 6 h LPS-treated rabbits. Western and Northern blot analysis revealed a marked reduction in the protein and mRINA levels of Gsα, but not Giα, in septic myocardium. We conclude that the inotropic response to β-adrenoceptor stimulation is impaired in myocardium from LPS-induced septic rabbits. This did not appear to be due to an overproduction of nitric oxide or a decrease in myocardial β-adrenoceptor numbers, but was related to the reduced expression of Gaα protein and mRNA levels.
The difference in histamine receptor subtypes that are involved in the positive inotropic effect of histamine in guinea pig and rabbit ventricular myocardium was analytically characterized. In guinea ...pig papillary muscles, the positive inotropic effect of histamine was antagonized by cimetidine but not by mepyramine. The converse was true in rabbit papillary muscles. However, histamine evoked a positive inotropic effect through H_1 - and H_2 -receptors after blockade of H_2 - and H_1 -receptors in guinea pig and rabbit papillary muscles, respectively. Adenylate cyclase was significantly activated by histamine via H_2 -receptors in guinea pig but not in rabbit myocardial ventricular membranes. Accumulation of ^^3 Hinositol monophosphate in ventricular strips prelabeled with myo-^^3 Hinositol was increased by histamine via H_1 -receptors to a similar extent in rabbits and guinea pigs. Radioligand binding experiments with ^^3 Hmepyramine and ^^3 Htiotidine showed an increased number of H_1 -receptors and a decreased number of H_2 -receptors in guinea pig compared with rabbit ventricular myocardium. These results suggest that the positive inotropic effects of histamine are dominated by an H_1 -receptor-mediated effect in rabbits and by an H_2 -receptor-mediated one in guinea pig ventricular myocardium, and the positive inotropic effect manifested by one subtype apparently restricts the expression of the positive inotropic effect mediated by the other subtype. This species difference is not due to a difference in densities of the receptor subtypes, but may be partly related to a difference in the extents of coupling of H_2 -receptors to adenylate cyclase.
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