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Biomedical subjects

M Marsili

Publications and source records attributed to M Marsili.

At least 55 records · Page 3Linked to original sources

Alterations in the fine structure of the pig liver upon cold ischemia.

The fine structure of the pig liver was examined after 30 min of warm ischemia at 37 degrees C, after 2 h of cold ischemia at 4 degrees C and after 30 min of warm ischemia followed by a further 30 min of cold ischemia. After warm ischemia, limited mitochondrial swelling was observed in hepatocytes. After cold ischemia, alone or following warm ischemia, vesiculation and vacuolation of the hepatocyte cytoplasm and appearance of intrasinusoidal blebs deriving from hepatocytes were observed with different intensity among the animals. These findings suggest that cooling and storing the liver at 4 degrees C may lead to injury, which could negatively influence the viability of the organ, with different intensity from case to case.

Animals↗

Veno-venous bypass in experimental liver transplantation: portal-jugular versus caval-portal-jugular.

This study was undertaken to compare the changes in physiologic variables caused by the use of two different types of pump-assisted veno-venous bypass during experimental liver transplantation. The experiments, performed on female pigs weighing 30 +/- 2 kg, were divided into two groups depending on the bypass used. During the anhepatic phase a pump-assisted portal-jugular (PJ) bypass was used in Group 1 (n = 8) at a flow rate of 15 ml kg-1-min-1, while a pump-assisted caval-portal-jugular (CPJ) bypass was used in Group 2 (n = 8) at a flow rate of 20 ml kg-1-min-1. Intraoperative haemodynamics, pulmonary gas exchange, haematological and serum biochemical parameters were evaluated. Postoperative animal survival rate and complications associated with the bypass used were evaluated. Mean pulmonary artery pressure (Ppa) and pulmonary vascular resistance (Pvr) showed significantly different behaviour in the two groups, whereas the remaining parameters all showed the same trend. Thus an earlier and more substantial increase in Ppa and Pvr values was found in Group 1 when compared to Group 2 during the anhepatic phase. The different behaviour shown by Group 1 may depend on the release of circulating vasoactive substances generated following pelvic venous congestion caused by the temporary clamping of the inferior vena cava. In conclusion, this study indicates that the pump-assisted CPJ bypass is more suitable than the pump-assisted PJ bypass. Furthermore, in order to obtain better results it should be used routinely in porcine liver transplantation.

Anesthesia, General↗

A comparative chemometric study of QSAR descriptors.

Traditional descriptors for Qsar models are compared with two alternative blocks obtained by computer chemistry tools: electronic densities and principal properties. All three sets show similar prediction abilities by PLS modelling.

Models, Chemical↗

Defibrotide in extracorporeal circulation on healthy rabbits.

Defibrotide, a partially depolymerized DNA fraction obtained from mammalian lung, was found to have significant antithrombotic and fibrinolytic activities. On the basis of this evidence defibrotide could be of clinical value during hemoperfusive treatment. The present study was designed to evaluate the biological tolerance of this technique in a model of extracorporeal circulation, using an original Silastic apparatus, with defibrotide (0.83 mg/kg-1/min-1 after a 50 mg/kg-1 bolus injection) and heparin (0.66 IU/kg-1/min-1 after a 400 IU/kg-1 bolus injection) in ten rabbits (Group 1) and heparin only in ten others (Group 2, control group). In this study defibrotide produced a significantly lower pressure inside the circuit compared to the control group and gave a protective effect against those pathological changes which appeared during extracorporeal circulation and that may be considered omens of a state of shock. However the use of defibrotide in addition to heparin seemed to have a poor effect on platelet and leukocyte count alterations during application of this technique.

Animals↗

Experimental study of argon laser-induced microthrombosis during PGI2 infusion.

In order to evaluate the Argon laser-induced microthrombogenesis during prostacyclin (PGI2) infusion on newly formed microcirculation in the rabbit ear chamber, time-space parameters have been calculated in 118 observations subdivided into 4 groups according to the type and size of the vessels irradiated. The observations were carried out without drug treatment, with continuous infusion of pH 10.5 glycine buffer and with continuous infusion of PGI2 at the dosage of 125 ng X kg-1 X min-1 diluted in the glycine buffer. The results indicated that during PGI2 infusion the size of the thrombus, measured by maximal thrombus area, was always significantly less extended than in untreated animals. Moreover, the number of emboli detached during the first 5 min after laser exposure, measured by rate of embolization, during PGI2 infusion in venules and in the larger arterioles was smaller than in untreated animals. The vasoconstriction which usually takes place in the arteriolar vessels--upstream and downstream from the irradiated site--was in no way modified by the infusion of PGI2. Finally, it was noted that glycine buffer infusion showed an unforeseen activity on laser-induced vascular reactivity.

Animals↗

Increased survival in experimental dog heatstroke after reduction of gut flora.

A study was undertaken to determine if gut flora contribute to the pathophysiology of experimental canine heatstroke. Fifty animals in four groups were anesthetized with sodium pentobarbital (25 mg/kg) intravenously. An air temperature of 42-46 degrees C was maintained adjacent to the dog with a water-heated blanket for approximately 2 h until rectal temperatures rose to 43.5 +/- 0.4 degrees C. Animals were then cooled passively in room air (28 degrees C, 20% RH) until death or until 18 h elapsed, and were euthanized. Reduction of intestine stool and bacterial contents with antibiotics, cathartics, and enemas prior to heatstroke increased the incidence of 18-h survival from 20.0% to 70.6%; antibiotics administered after heatstroke did not alter the incidence of survival over control values. These data suggest that gut flora, presumably through endotoxemia, contribute to the evolution of heatstroke pathophysiology.

Animals↗

Peritoneal lavage cooling in an anesthetized dog heatstroke model.

This study was undertaken to compare cooling in room air (27 degrees C, 20% RH), ice slush surface cooling, and peritoneal lavage cooling (6-10 degrees C) as methods for lowering body temperature in an anesthetized dog heatstroke model. We anesthetized 19 animals with sodium pentobarbital (25 mg/kg) intravenously, and maintained them in an ambient temperature of 42-46 degrees C with a water heating blanket approximately 2.0 h until rectal temperatures rose to 43.2 +/- 0.2 degrees C. At the maximum rectal temperature, the heating blankets were removed, and animals were cooled, observed until death occurred or 18 h elapsed, and then sacrificed. The data demonstrate that maximum cooling rates of rectal temperature were: peritoneal lavage, 0.56 degrees C/min; ice slush, 0.11 degrees C/min; and 27 degrees C air cooling, 0.06 degrees C/min. The incidence of 18-h survival for lavage-cooled dogs when supported with normothermic dialysis every 4 h was significantly greater than for either ice slush or air cooled dogs.

Animals↗

An anesthetized dog heatstroke model.

This study was undertaken to develop an anesthetized dog heatstroke model. Forty-six animals were anesthetized with pentobarbital sodium (25 mg/kg) intravenously, and maintained at an ambient temperature of (42-46 degrees C) with a water-heated blanket over 2.5-3.0 h until rectal temperatures rose to 43.0-44.5 degrees C. Animals then cooled passively until death occurred or until 18 h elapsed, and were prepared for autopsy. Liver, kidney, and brain temperature, mean weighted skin temperature, mean weighted surface heat loss, and metabolic rates were obtained. There were no significant differences between liver, kidney, brain, and rectal temperatures during the heating and cooling periods. Cardiac output rose to 127% of initial value, and dropped rapidly to zero at 43.4 degrees C rectal temperature. The rapid decline was accompanied by a doubling of heart rate and a rapid drop in blood pressure and respiratory rate. Cheyne-Stokes respiration and apnea preceded bradycardia followed by asystole or ventricular fibrillation. Certain serum constituents demonstrated modest elevations suggestive of widespread tissue damage. Autopsy did not reveal a clear pattern of heat injury, with the exception of consistent congestion of the major organs and karyorrhexis of lymphocytes. These data are in agreement with similar data from human heatstroke victims and other heatstroke modeling in dogs, and support the concept that the anesthetized dog can in many respects provide an adequate model for human heatstroke.

Anesthesia, Intravenous↗

Influence of liver metabolism on the actions of althesin and thiopentone.

To examine the role of liver metabolism on the actions of Althesin, its duration of action and circulatory effects were measured under the following experimental conditions in the rat: (a) non pretreated rats; (b) non pretreated rats: injection through the portal vein; (c) rats with cholestasis; (d) rats with induced microsomal enzymes; (e) rats with a depressed microsomal enzymatic synthesis. The experiments were repeated in the same animals by injecting equivalent doses of thiopentone. The effects of Althesin depend upon the functional conditions of the liver, while a relationship of this kind does not occur with thiopentone.

Alfaxalone Alfadolone Mixture↗