The Journal of surgical research
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To characterize the mesenteric alpha1- and alpha2-adrenoceptor populations in newborn piglets, an extracorporeal circuit was established to control intestinal blood flow in 0- to 2-day old and 10- to 14-day old animals. In both groups, alpha-adrenoceptor activation was first documented by observing dose-dependent increases in mesenteric perfusion pressure after intramesenteric arterial injection of alpha-adrenoceptor agonists. ⋯ In addition, mesenteric vasoconstrictor responses to other known vasoconstrictor agents--angiotensin II, neuropeptide Y, and a thromboxane A2 mimic (U-46619)--were not effected in either age group by prazosin or yohimbine, implying these agents act independently of alpha-adrenoceptor mechanisms. These data suggest that (1) there exists functional mesenteric alpha1- and alpha2-adrenoceptor-like activity in 10- to 14-day old piglets that, in 0- to 2-day old animals, is not specifically expressed; and (2) mesenteric alpha-adrenoceptor function becomes more selective as newborn piglets mature.
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Translocation of bacteria and endotoxin leading to sepsis occurs in animals subjected to burns or intestinal ischemia. This may be mediated in part by bowel mucosal microcirculatory dysfunction. However, the direct effect of sepsis on the mucosal microcirculation is unknown. ⋯ The intercapillary areas were also more highly variable in the CLP group (median coefficient of variation 102 vs 83% in the sham group, P = 0.025). Intravital microscopy may be used to examine microcirculatory function of the small bowel mucosa. Sepsis induced by CLP leads to a decrease in the number of perfused capillaries in the small bowel mucosa.
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With the advent of transjugular intrahepatic porta-systemic stent shunt and the wider application of the surgically placed small diameter prosthetic H-graft portacaval shunt (HGPCS), partial portal decompression in the treatment of portal hypertension has received increased attention. The clinical results supporting the use of partial portal decompression are its low incidence of variceal rehemorrhage due to decreased portal pressures and its low rate of hepatic failure, possibly due to maintenance of blood flow to the liver. Surprisingly, nothing is known about changes in portal hemodynamics and effective hepatic blood flow following partial portal decompression. ⋯ In contrast to the significant decreases in portal pressures, portal vein blood flow and effective hepatic blood flow do not decrease significantly. Changes in portal vein pressures and portal vein-inferior vena cava pressure gradients are great when compared to changes in portal vein flow and effective hepatic blood flow. Reduction of portal hypertension with concomitant maintenance of hepatic blood flow may explain why hepatic dysfunction is avoided following partial portal decompression.
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A thoracic electric bioimpedance device with improved signal processing was used to noninvasively measure cardiac output in eight New Zealand White rabbits (average wt = 4.7 kg). Prospective correlation was performed between aortic thermodilution and impedance cardiography in a closed chest model. Aortic thermodilution was compared to the electromagnetic flowmeter in an open chest model. ⋯ A statistically significant decline in the mean magnitude of the dZ/dt signal tracing (1.6 +/- 0.10 V-pre, 0.31 +/- 0.4 V-post, P < 0.005, n = 21) was observed upon aortic arch occlusion. conversely, pulmonary artery occlusion did not have a statistical effect on the impedance signal (1.07 +/- 0.09-pre, 0.95 +/- 0.08-post, P > 0.05, n = 20). In conclusion, a significant correlation was observed between impedance cardiography and aortic thermodilution in measurement of cardiac output in sedated, anesthetized rabbits. This simple technique which involves application of skin electrodes may prove useful in measurement of cardiac output in surgical experimental small animal models.(ABSTRACT TRUNCATED AT 250 WORDS)
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A common method for calculating energy needs (PEE) in acute trauma patients is multiplying the Harris-Benedict equation (BEE) by activity factors (AF) and variable stress factors (SF) depending on the injury severity. Selection of the SF can be an arbitrary and potentially inaccurate decision. The purposes of this study were: (1) to investigate the relationship between injury severity score (ISS) to postinjury energy expenditure (MEE), and (2) to compare the MEE to PEE when using the SF of 1.75. ⋯ There was a significant correlation (r = 0.772, P < 0.05) between PEE and MEE when using the SF of 1.75 for all of the patients. These results suggest that there is not a correlation between ISS and subsequent MEE in major trauma patients. In addition, using the SF of 1.75 will closely estimate energy needs in acute trauma patients.