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Biomedical subjects

M Angelescu

Publications and source records attributed to M Angelescu.

At least 19 recordsLinked to original sources
PubMed2001

Characterization of renal parenchymal perfusion during experimental infrarenal aortic clamping and declamping with enhanced thermodiffusion electrodes.

Despite multiple previous experimental and clinical investigations, it has not been fully clarified until now whether infrarenal aortic cross-clamping (IRAC) induces a significant disturbance of renal parenchymal perfusion. Most renal cortical flow data collected thus far have been heterogenous because of inherent limitations of available measurement technology. The enhanced thermal diffusion (TD) electrode is a newly developed and previously validated prototype device that allows continuous quantification of parenchymal kidney perfusion after local probe implantation. We monitored renal perfusion during experimental IRAC with TD for the first time, thereby also evaluating the potential applicability of the method in clinical aortic surgery. IRAC (20 min) followed by sudden declamping was performed in pigs under general anesthesia (n = 14). Renal cortical blood flow (RCBF) was continuously quantified by TD, total aortic flow (TABF) and renal artery flow (RABF) were measured by ultrasonic flow probes, and parameters of systemic circulation were determined by Swan-Ganz catheter. Our results showed that kidney perfusion can be continuously quantified using TD electrodes during experimental aortic surgery in a porcine model. IRAC does not lead to a significant impairment of RCBF in young pigs as measured by TD. Renal perfusion appears to be predominantly pressure driven. Consequently, abrubt aortic declamping can bring about prolonged renal ischemia. Transfer of the TD method to RCBF monitoring during clinical aortic surgery appears to be feasible and should be investigated in selected cases.

Animals↗
PubMed2001

Endothelin-1 and big-endothelin concentrations are elevated in liver graft tissue during cold storage and reperfusion.

Endothelin (ET) and its precursor big-ET were synchronously analyzed by RIA in liver biopsies and systemic plasma during porcine orthotopic liver transplantation (OLT) before graft harvesting (phase A), after cold storage (phase B), and early (phase C) and late reperfusion (phase D). Tissue and plasma concentrations were correlated with length of survival and reperfusion. Increased tissue ET/big-ET levels were already detected during phase B (ET: 46 +/- 20; big-ET: 245 +/- 119 pg/mg cytosolic protein) and remained elevated in phase C (ET: 49 +/- 16; big-ET: 306 +/- 144 pg/mg) compared to baseline (ET: 32 +/- 13; big-ET: 185 +/- 164 pg/mg; p < 0.05). In phase D, a rapid concentration decline was detected (ET: 36 +/- 26; big-ET: 163 +/- 138 pg/mg). Systemic ET levels were elevated in phase B (3.4 +/- 3.0 pg/ml), C, (2.8 +/- 1.2 pg/ml) and D (2.6 +/- 2.0 pg/ml), compared to baseline (1.7 +/- 1.1 pg/ml; p < 0.05). ET/big-ET kinetics in liver tissue and systemic plasma showed analogous characteristics. Intrahepatic ET accumulation during storage and early reperfusion could be of relevance for harvest-related disturbances of hepatic microcirculation.

Animals↗
PubMed1999

[Current management of hepatic, biliary and pancreatic trauma].

The management of hepatic trauma should be, if possible, non-operative and is initially determined by hemodynamic stability, absence of coagulopathy and limited need for blood transfusions. In hemodynamically unstable patients specific attempts to control intraparenchymal hemorrhage and resection are contraindicated. Perihepatic packing is the therapy of choice. If the hemorrhage cannot be controlled, parenchymal resection or hepatectomy with subsequent transplantation must be performed. Biliary leakage is the cause of chronic complications. The current management of intraparenchymal lesions consists of longterm drainage or stenting as combined radiological and endoscopical techniques. Pancreatic ruptures without ductal injury are treated non-operatively or by external drainage. Ductal lesions with persistent fistulas are handled depending on localization either by distal resection, pancreaticojejunostomy of the injured segment, or partial pancreaticoduodenectomy if massive disruption of the pancreatic head, duodenum or bile duct are present.

Abdominal Injuries↗
PubMed1998

[Disorders of hepatic microcirculation as early manifestation of rejection in clinical liver transplantation].

By means of thermodiffusion, monitoring of hepatic microcirculation was performed in 43 patients during the first week after liver transplantation. A significant decrease of liver perfusion was registered in 15 patients with early rejection. The disturbance of hepatic microcirculation preceded the increase of transaminases by 36 hours and the subsequent biopsy by 60 hours. Already 12 hours after the beginning of corticoid therapy liver perfusion started to recover. The quantification of hepatic microcirculation may facilitate faster diagnosis and treatment of early rejection following liver transplantation.

Graft Rejection↗
PubMed1996

Anticoagulant effects and tissue factor pathway inhibitor after intrapulmonary low-molecular-weight heparin.

The present study was designed to investigate the anticoagulant action of inhaled low-molecular-weight (LMW) heparin on the release of tissue factor pathway inhibitor (TFPI) and on antifactor Xa activity, Heptest, activated partial thromboplastin time (APTT) and thrombin clotting time (TCT) in healthy volunteers. 3000 IU (group 1), 9000 IU (group 2), 27,000 IU (group 3) or 54,000 IU (group 4) LMW-heparin were given to 20 healthy volunteers each at 4 weeks intervals by inhalation. For safety reasons a dose escalating design was chosen. APTT and TCT did not change after inhalation of any dose of LMW-heparin as well as all parameters in group 1. In group 2, Heptest coagulation times were prolonged from 18.7 +/- 2.0 s before to 26.1 +/- 5.2 s 6 h and 20.5 +/- 1.9 s 24 h after inhalation and the other parameters remained uneffected. In group 3, S2222 method and the protamine assay increased from 0.01 to about 0.1 IU/ml 6 h after inhalation and returned to normal values after 24 h. TFPI antigen increased from 74.1 +/- 13.9 to 80.5 +/- 14.2 ng/ml 3 h after inhalation. TFPI activity remained unchanged. Heptest coagulation values were prolonged to 42 +/- 7.6 s after 6 h and returned to normal within 72 h after inhalation. In group 4, the following changes were observed: antifactor Xa activity increased to 0.343 +/- 0.196 U/ml after 6 h and normalized after 72 h. The protamine assay detected 0.2 +/- 0.18 U LMWH/ml after 6 h, TFPI antigen increased to 103 +/- 17.9 ng/ml and TFPI activity to 1.14 +/- 0.23 U 3 h after inhalation. All tests were normal after 24 h. Heptest coagulation values increased to 77.5 +/- 11.8 s 6 h after inhalation and normalized after 144 h. The area under the activity time curve of the S2222 method and of the Heptest assay increased with increasing doses (r = 0.677 and r = 0.571), respectively. The calculated elimination half-life of the aXa-effect was 7.5 h using S2222-, Heptest- and protamine assays. The data demonstrate a resorption of LMW-heparin by intrapulmonary route in man. The dose to produce antifactor Xa levels, prolongations of Heptest coagulation values and in releasing TFPI is about ten-fold higher than after subcutaneous administration.

Administration, Inhalation↗