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Publications (3)24.01 Total impact

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    ABSTRACT: Upper gastrointestinal (GI) bleeding in cirrhotic patients has a high incidence of mortality and morbidity. Postbleeding catabolism has been hypothesized to be partly due to the low biological value of hemoglobin, which lacks the essential amino acid isoleucine. The aims were to study the metabolic consequences of a "simulated" upper GI bleed in patients with cirrhosis of the liver and the effects of intravenous infusion of isoleucine. Portal drained viscera, liver, muscle, and kidney protein kinetics were quantified using a multicatheterization technique during routine portography. Sixteen overnight-fasted, metabolically stable patients who received an intragastric infusion of an amino acid solution mimicking hemoglobin every 4 hours were randomized to saline or isoleucine infusion and received a mixture of stable isotopes (L-[ring-2H5]phenylalanine, L-[ring-2H4]tyrosine, and L-[ring-2H2]tyrosine) to determine organ protein kinetics. This simulated bleed resulted in hypoisoleucinemia that was attenuated by isoleucine infusion. Isoleucine infusion during the bleed resulted in a positive net balance of phenylalanine across liver and muscle, whereas renal and portal drained viscera protein kinetics were unaffected. In the control group, no significant effect was shown. CONCLUSION: The present study investigated hepatic and portal drained viscera protein metabolism selectively in humans. The data show that hepatic and muscle protein synthesis is stimulated by improving the amino acid composition of the upper GI bleed by simultaneous intravenous isoleucine administration.
    Hepatology 04/2007; 45(3):560-8. · 12.00 Impact Factor
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    ABSTRACT: Upper gastrointestinal (UGI) bleeding in cirrhosis is associated with enhanced ammoniagenesis, the site of which is thought to be the colon. The aims of this study were to evaluate interorgan metabolism of ammonia following an UGI bleed in patients with cirrhosis. Study 1: UGI bleed was simulated in 8 patients with cirrhosis and a transjugular intrahepatic portasystemic stent-shunt (TIPSS) by intragastric infusion of an amino acid solution that mimics the hemoglobin molecule. We sampled blood from the femoral artery and a femoral, renal, portal, and hepatic vein for 4 hours during the simulated bleed and measured plasma flows across these organs. Study 2: In 9 cirrhotic patients with an acute UGI bleed that underwent TIPSS insertion, blood was sampled from an artery and a hepatic, renal, and portal vein, and plasma flows were measured. Study 1: During the simulated bleed, arterial concentrations of ammonia increased significantly (P =.002). There was no change in ammonia production from the portal drained viscera, but renal ammonia production increased 6-fold (P =.008). In contrast to an unchanged ammonia removal by the liver, a significant increase in muscle ammonia removal was observed. Study 2: In patients with an acute UGI bleed, ammonia was only produced by the kidneys (572 [184] nmol/kg bw/min) and not by the splanchnic area (-121 [87] nmol/kg bw/min). In conclusion, enhanced renal ammonia release has an important role in the hyperammonemia that follows an UGI bleed in patients with cirrhosis. During this hyperammonemic state, muscle is the major site of ammonia removal.
    Hepatology 07/2003; 37(6):1277-85. · 12.00 Impact Factor
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    ABSTRACT: The occurrence of acute cellular rejection after orthotopic liver transplantation is common. At present, no allowance is made in immunosuppressive regimens for parameters other than weight. We investigated parameters in 121 consecutive patients receiving their primary allograft to determine if there are pretransplantation factors predicting the occurrence of acute cellular rejection after transplantation. The case notes and dietetic notes of these patients were reviewed for age at transplantation, cause of liver disease, preoperative albumin and creatinine levels, lymphocyte count, anthropometric measurements, donor age, HLA DR mismatch, and cold ischemia time. Acute cellular rejection was more likely to occur in younger patients, patients with Child's class A disease, and those with normal midarm muscle circumference. Acute rejection was increased in transplant recipients from donors aged younger than 30 and older than 50 years. Acute cellular rejection was less likely to occur in patients who underwent transplantation for alcoholic liver disease. Chronic rejection was significantly increased in women and those patients who experienced recurrent acute rejection. On multivariate analysis, the only significant predictor was the decreased likelihood of acute rejection in patients with depleted midarm muscle circumference. In conclusion, it may be possible to individualize immunosuppressive regimens on the basis of pretransplantation characteristics.
    Liver transplantation and surgery: official publication of the American Association for the Study of Liver Diseases and the International Liver Transplantation Society 12/1999; 5(6):475-9.