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Biomedical subjects

M A López-Boado

Publications and source records attributed to M A López-Boado.

At least 19 recordsLinked to original sources
PubMed2000

L-arginine reduces liver and biliary tract damage after liver transplantation from non-heart-beating donor pigs.

BACKGROUND: To evaluate whether L-arginine reduces liver and biliary tract damage after transplantation from non heart-beating donor pigs. METHODS: Twenty-five animals received an allograft from non-heart-beating donors. After 40 min of cardiac arrest, normothermic recirculation was run for 30 min. The animals were randomly treated with L-arginine (400 mg x kg(-1) during normothermic recirculation) or saline (control group). Then, the animals were cooled and their livers were transplanted after 6 hr of cold ischemia. The animals were killed on the 5th day, liver damage was assessed on wedged liver biopsies by a semiquantitative analysis and by morphometric analysis of the necrotic areas, and biliary tract damage by histological examination of the explanted liver. RESULTS: Seventeen animals survived the study period. The histological parameters assessed (sinusoidal congestion and dilatation, sinusoidal infiltration by polymorphonuclear cells and lymphocytes, endothelitis, dissociation of liver cell plates, and centrilobular necrosis) were significantly worse in the control group. The necrotic area affected 15.9 +/- 14.5% of the liver biopsies in the control group and 3.7 +/- 3.1% in the L-arginine group (P<0.05). Six of eight animal in the control group and only one of eight survivors in the L-arginine group developed ischemic cholangitis (P<0.01). L-Arginine administration was associated with higher portal blood flow (676.9 +/- 149.46 vs. 475.2 +/- 205.6 ml x min x m(-2); P<0.05), higher hepatic hialuronic acid extraction at normothermic recirculation (38.8 +/- 53.7% vs. -4.2 +/- 18.2%; P<0.05) and after reperfusion (28.6 +/- 55.5% vs. -10.9 +/- 15.5%; P<0.05) and lower levels of alpha-glutation-S-transferase at reperfusion (1325 +/- 1098% respect to baseline vs. 6488 +/- 5612%; P<0.02). CONCLUSIONS: L-Arginine administration during liver procurement from non heart beating donors prevents liver and biliary tract damage.

Animals↗
PubMed1999

Evaluation of ischemic injury during liver procurement from non-heart-beating donors.

UNLABELLED: The aim of this study was to assess liver viability after different periods of cardiac arrest and the predictive value of two markers of ischemia-reperfusion injury. METHODS: A pig liver transplantation model of non-heart-beating donors was studied. Four donor groups were designed; three groups were submitted to different periods of cardiac arrest (20, 30 and 40 min), and the fourth group served as the control group (without cardiac arrest). In the non-heart-beating donor groups, normothermic recirculation was established 30 min prior to total body cooling. Aminotransferase, alpha-glutathione-S-transferase, and hyaluronic acid determinations as well as liver biopsies, were serially performed. RESULTS: Although hepatocellular function could be preserved after 40 min of cardiac arrest, histological lesions at 5 days were considered irreversible due to the presence of a necrotic biliary tract. An overall significant relationship was found between the time period of cardiac arrest (20, 30 or 40 min) and the levels of hyaluronic acid (p = 0.004) or alpha-glutathione-S-transferase (p = 0.01) obtained during liver procurement and transplantation. CONCLUSIONS: The period of cardiac arrest is the determinant factor of liver viability after liver transplantation from non-heart-beating donors. As early markers of endothelial or hepatocellular damage, hyaluronic acid or alpha-glutathione-S-transferase levels may help to evaluate the ischemic injury of a potential donor.

Alanine Transaminase↗
PubMed1998

Hepatic blood flow and oxygen extraction ratio during normothermic recirculation and total body cooling as viability predictors in non-heart-beating donor pigs.

BACKGROUND: Our aim was to evaluate the hepatic blood flows and oxygen metabolism of non-heart-beating donor (NHBD) pigs, with the use of cardiopulmonary bypass (CPB) and normothermic recirculation (NR) before total body cooling, and its relationship with recipient survival. METHODS: Thirty-five pigs were transplanted with an allograft from NHBDs. After warm ischemia (WI) time (20, 30, or 40 min), CPB and NR were run for 30 min. After this period, the animals were cooled to 15 degrees C. In the control group (20 min of WI), the period of NR was excluded. Liver procurement was then performed. RESULTS: Survival rate was 100% in the 20WI, 70% in the 30WI, and 50% in the 40WI. Control group survival rate was 0%. Hepatic artery blood flow and portal blood flow recovered during NR. Pump blood flow during CPB increased rapidly during NR and was significantly higher in the 20WI. When donors of the livers transplanted in "surviving pigs" (DSP) were compared with donors of the livers transplanted in "nonsurviving pigs" (DNSP), hepatic artery blood flow, portal blood flow, and pump blood flow were higher in the DSP. Hepatic oxygen extraction ratio increased in the three groups with respect to baseline values. Hepatic oxygen extraction ratio was lower in the 20WI than in the other groups and was lower in the DSP than in the DNSP. CONCLUSIONS: The use of a NR period before total body cooling improves survival of liver transplantation in NHBDs. Portal blood flow and pump blood flow measurements can predict the viability of the grafts.

Animals↗
PubMed1998

Vena cava vascular reconstruction during orthotopic liver transplantation: a comparative study.

The aim of this study was to evaluate the influence of preserving the recipient's inferior vena cava during orthotopic liver transplantation (OLT) on hemodynamic alterations, blood component requirements, postoperative liver and renal function, as well as vascular-related complications. A total of 122 OLTs was studied. In 35 OLTs, venovenous bypass (BP) was used; in 35 OLTs, bypass was not used (NBP); and in 52 OLTs, the recipient's inferior vena cava was preserved (PC). Preservation of the inferior vena cava means that venous return is not compromised at any time during transplantation. The time of hepatectomy was not different among the three groups (208 +/- 11, 188 +/- 13, and 194 +/- 6 minutes for BP, NBP, and PC, respectively); however, the total operating time was significantly lower in PC patients (492 +/- 24, 459 +/- 18, and 419 +/- 10 minutes for BP, NBP, and PC, respectively; P = .004, ANOVA). Blood component requirements were significantly lower in patients with PC. For red blood cells, these were 15.2 +/- 2.6, 16 +/- 3.4, and 7.1 +/- 1.5 units for BP, NBP, and PC, respectively (P = .009, ANOVA), and for fresh-frozen plasma, these were 5.4 +/- .7, 5.8 +/- .9, and 3 +/- .4 L for BP, NBP, and PC, respectively (P = .005, ANOVA). Postoperative liver and renal function did not differ among the three groups. The incidence of surgical complications (bleeding and vascular) was similar. Preservation of the inferior vena cava of the recipient significantly reduces the magnitude of OLT.

Blood Transfusion↗
PubMed1998

Liver conditioning after cardiac arrest: the use of normothermic recirculation in an experimental animal model.

The aim of this study was to compare the possible role of normothermic recirculation with the role of liver transplants from non-heart-beating donor pigs after 20 min of cardiac arrest. Three groups were studied, of which two were control groups: group 1, in which the liver was harvested from a heart-beating donor; group 2, in which the liver was harvested after a period of cardiac arrest followed by total body cooling; and group 3, in which the liver was procured as in group 2, but including a period of 30 min of cardiopulmonary bypass and tissue oxygenation at 37 degrees C before total body cooling. Survival at 5 days; endothelial (hyaluronic acid) and hepatocellular damage (AST, ALT, and alpha-GST); adenine nucleotides (energy charge), and histological changes were evaluated. Normothermic recirculation during 30 min showed a significant effect on survival (p = .03), endothelial damage (p < .05), and histological changes after reperfusion (p = .04). Cardiopulmonary bypass significantly increased the energy charge during the normothermic recirculation period (p = .001). Moreover, this study shows that a significant survival (100%) can be achieved with a liver allograft after 20 min of cardiac arrest. Although the liver suffers a major insult in terms of endothelial damage and hepatocellular damage, lesions caused by the ischemic injury are reversible. Histological changes also indicate lesion reversibility, since they almost disappear after 5 days.

Adenine Nucleotides↗
PubMed1996

[Asymptomatic pneumoperitoneum after fiber gastroscopy].

A case of asymptomatic pneumoperitoneum after fiber gastroscopic sclerosis of bleeding gastric erosions is presented. Air bubbles in gastric curvatures without evidence of macroscopic perforation were found at laparotomy. We comment the etiologies of pneumoperitoneum without macroscopic perforation and suggest that the management of patients with asymptomatic pneumoperitoneum with normal clinical examination and blood analysis might be conservative to avoid needless laparotomies.

Aged↗
PubMed1993

Pancreatic ascites.

Pancreatic ascites is the accumulation of high protein, amylase-rich intraperitoneal fluid which occurs during the course of chronic pancreatitis, in association with rupture of a pseudocyst or disruption of a pancreatic duct. This is an uncommon complication, with less than 250 cases reported in the literature. We have treated 6 patients with pancreatic ascites. Five were males with a history of chronic alcoholism, but no known pancreatic disease. The diagnosis was made by ascitic tap and the site of the leakage identified by ERCP. Treatment was initiated with total parenteral nutrition in all cases. In 5 patients, the ascites failed to respond to medical therapy. Surgical intervention was indicted in 3 of these patients. The diagnosis of pancreatic ascites should be considered in patients with refractory ascites, and a combination of medical care and judicious surgery have contributed to an improved outcome.

Adolescent↗
PubMed1992

Pancreas prostanoid production in ischemia and reperfusion.

This study was carried out to investigate the proportion of the 6-keto prostaglandin F1 alpha (6-keto PGF1 alpha) and thromboxane B2 (TXB2) alteration that is due to ischemia in pancreas transplantation against the proportion due to reperfusion. For this purpose, Lewis rats were divided in three experimental groups: Group I = Control, Group II = Donor pancreas subjected to 15 minutes of cold ischemia, Group III = Same as group II but pancreas were transplanted to the recipient individual and then subjected to reperfusion. The results indicate that increases in pancreas 6-keto PGF1 alpha occur as a consequence of cold ischemia while TXB2 remains unchanged. When blood flow was restored, 6-keto PGF1 alpha remained unchanged compared to the ischemic group while pancreatic levels of TXB2 were significantly increased. These results suggest a different induction of prostanoid metabolism during ischemia and reperfusion in pancreatic tissue.

6-Ketoprostaglandin F1 alpha↗