Continuous Infusion of Iohexol to Monitor Perioperative Glomerular Filtration Rate.

Continuous monitoring of the glomerular filtration rate (GFR) in the perioperative setting could provide valuable information about acute kidney injury risk for both clinical and research purposes. This pilot study aimed to demonstrate that GFR measurement by a continuous 72 hrs iohexol infusion in patients undergoing colorectal cancer surgery is feasible. Four patients undergoing robot-assisted colorectal cancer surgery were recruited from elective surgery listings.

Vitamin K catabolite inhibition of ovariectomy-induced bone loss: structure-activity relationship considerations.

Scope: The potential benefit of vitamin K as a therapeutic in osteoporosis is controversial and the vitamin K regimen being used clinically (45 mg/day) employs doses that are many times higher than required to ensure maximal gamma-carboxylation of the vitamin K-dependent bone proteins. We therefore tested the hypothesis that vitamin K catabolites, 5-carbon (CAN5C) and 7-carbon carboxylic acid (CAN7C) aliphatic side-chain derivatives of the naphthoquinone moiety exert an osteotrophic role consistent with the treatment of osteoporosis.

Methods And Results: Osteoblast-like MG63 cell cultures were challenged with lipopolysaccharide and the levels of interleukin-6, an osteoclastogenic cytokine, measured with and without catabolites; low concentrations of CAN7C significantly inhibited interleukin-6 release, but CAN5C did not.

L-ornithine and phenylacetate synergistically produce sustained reduction in ammonia and brain water in cirrhotic rats.

Unlabelled: Treatment of hyperammonemia and hepatic encephalopathy in cirrhosis is an unmet clinical need. The aims of this study were to determine whether L-ornithine and phenylacetate/phenylbutyrate (administered as the pro-drug phenylbutyrate) (OP) combined are synergistic and produce sustained reduction in ammonia by L-ornithine acting as a substrate for glutamine synthesis, thereby detoxifying ammonia, and the phenylacetate excreting the ornithine-derived glutamine as phenylacetylglutamine in the urine. Sprague-Dawley rats were studied 4 weeks after bile duct ligation (BDL) or sham operation.

Ammonia impairs neutrophil phagocytic function in liver disease.

Unlabelled: Hyperammonemia is a feature of liver failure, which is associated with increased risk of infection. The aims of the present study were to determine in vitro, in rats fed an ammoniagenic diet and in patients with cirrhosis, whether induction of hyperammonemia results in neutrophil dysfunction. As hyperammonemia produces cell swelling, we explored the role of the osmoregulating, p38 mitogen-activated protein kinase (p38(MAPK)) pathway in mediating this neutrophil dysfunction.

Neutrophil dysfunction in alcoholic hepatitis superimposed on cirrhosis is reversible and predicts the outcome.

Unlabelled: Mortality in patients with alcoholic hepatitis (AH) remains high, and although corticosteroids are widely used for treatment, the results vary considerably. In AH, neutrophils are primed and infiltrate the liver to produce injury, but paradoxically, the main cause of death in such patients is infection. Our prospective study addressed this paradox of primed neutrophils on the one hand and increased risk of infection on the other.

Increased gene and protein expression of the novel eNOS regulatory protein NOSTRIN and a variant in alcoholic hepatitis.

Background & Aims: Increased intrahepatic resistance in cirrhosis is associated with reduced endothelial NO synthase (eNOS) activity and exacerbated by superimposed inflammation. NOSTRIN induces intracellular translocation of eNOS and reduces NO generation. Our aims were to quantify and compare hepatic expression of eNOS, NOSTRIN, NOSIP, and caveolin-1 in alcoholic cirrhosis with or without superimposed alcoholic hepatitis and in normal livers.

Endotoxemia produces coma and brain swelling in bile duct ligated rats.

Unlabelled: This study explores the hypothesis that the inflammatory response induced by administration of lipopolysaccharide (LPS) exacerbates brain edema in cirrhotic rats; and if so whether this is associated with altered brain metabolism of ammonia or anatomical disturbance of the blood-brain barrier. Adult Sprague-Dawley rats 4 weeks after bile duct ligation (BDL)/Sham-operation, or naïve rats fed a hyperammonemic diet (HD), were injected with LPS (0.5 mg/kg, intraperitoneally) or saline, and killed 3 hours later.

Inflammation is an important determinant of levels of the endogenous nitric oxide synthase inhibitor asymmetric dimethylarginine (ADMA) in acute liver failure.

Acute liver failure (ALF) is characterized by rapid progressive organ failure and poor outcome. The pathophysiology of multiorgan dysfunction in ALF remains unclear but increased systemic inflammatory response is believed to be an important determining factor. Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, results from proteolysis and the liver is a major site for its metabolism.

Increasing dimethylarginine levels are associated with adverse clinical outcome in severe alcoholic hepatitis.

Unlabelled: Previous studies suggest reduced hepatic endothelial nitric oxide synthase activity contributes to increased intrahepatic resistance. Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, undergoes hepatic metabolism via dimethylarginine-dimethylamino-hydrolase, and is derived by the action of protein-arginine-methyltransferases. Our study assessed whether ADMA, and its stereo-isomer symmetric dimethylarginine (SDMA), are increased in alcoholic hepatitis patients, and determined any relationship with severity of portal hypertension (hepatic venous pressure gradient measurement) and outcome.

Hepatic guanylate cyclase activity is decreased in a model of cirrhosis: a quantitative cytochemistry study.

The production of nitric oxide (NO) in liver disease and its role in vascular control has been a subject of much interest in recent years. However, the activity of guanylate cyclase (GC), the enzyme activated by NO has received little attention with regard to liver disease. In this study we have utilised a quantitative cytochemical technique to examine the activity of GC on a per cell basis in a rat model of cirrhosis.

Effect of albumin dialysis on intracranial pressure increase in pigs with acute liver failure: a randomized study.

Background: Increased intracranial pressure (ICP) worsens the outcome of acute liver failure (ALF). This study investigates the underlying pathophysiological mechanisms and evaluates the therapeutic effect of albumin dialysis in ALF with use of the Molecular Adsorbents Recirculating System without hemofiltration/dialysis (modified, M-MARS).

Methods: Pigs were randomized into three groups: sham, ALF, and ALF + M-MARS.

Determination of the urinary aglycone metabolites of vitamin K by HPLC with redox-mode electrochemical detection.

We describe a method for the determination of the two major urinary metabolites of vitamin K as the methyl esters of their aglycone structures, 2-methyl-3-(3'-3'-carboxymethylpropyl)-1,4-naphthoquinone (5C-aglycone) and 2-methyl-3-(5'-carboxy-3'-methyl-2'-pentenyl)-1,4-naphthoquinone (7C-aglycone), by HPLC with electrochemical detection (ECD) in the redox mode. Urinary salts were removed by reversed-phase (C18) solid-phase extraction (SPE), and the predominantly conjugated vitamin K metabolites were hydrolyzed with methanolic HCl. The resulting carboxylic acid aglycones were quantitatively methylated with diazomethane and fractionated by normal-phase (silica) SPE.

Pathophysiological effects of albumin dialysis in acute-on-chronic liver failure: a randomized controlled study.

The pathophysiological basis of acute-on-chronic liver failure (ACLF) is unclear but systemic inflammatory response is thought to be important. In patients with ACLF, the molecular adsorbents recirculating system (MARS) improves individual organ function, but the effect of MARS on the proposed mediators of systemic inflammatory response is unclear. The present study was designed to determine the effect of MARS on the cytokine profile, oxidative stress, nitric oxide, and ammonia.

Anti-tumor necrosis factor-alpha monoclonal antibody therapy in severe alcoholic hepatitis.

Background/aims: Severe alcoholic hepatitis (AH) is associated with high mortality. Tumor necrosis factor-alpha (TNFalpha) has been demonstrated to play an important role in its pathophysiology.

Methods: Twelve patients with biopsy-confirmed AH and a Maddrey discriminant factor >32 were treated with a single infusion of the anti-TNF monoclonal antibody Infliximab at a dose of 5mg/kg body weight.