Normal or increased bile acid uptake in isolated mucosa from patients with bile acid malabsorption.

INTRODUCTION: Bile acid malabsorption as reflected by an abnormal Se-labelled homocholic acid-taurine (SeHCAT) test is associated with diarrhoea, but the mechanisms and cause-and-effect relations are unclear. OBJECTIVES: Primarily, to determine whether there is a reduced active bile acid uptake in the terminal ileum in patients with bile acid malabsorption. Secondarily, to study the linkage between bile acid malabsorption and hepatic bile acid synthesis. METHODS: Ileal biopsies were taken from patients with diarrhoea and from controls with normal bowel habits. Maximal active bile acid uptake was assessed in ileal biopsies using a previously validated technique based on uptake of C-labelled taurocholate. To monitor the hepatic synthesis, 7alpha-hydroxy-4-cholesten-3-one, a bile acid precursor, was assayed in blood. The SeHCAT-retention test was used to diagnose bile acid malabsorption. RESULTS: The taurocholate uptake in specimens from diarrhoea patients was higher compared with the controls [median, 7.7 (n=53) vs 6.1 micromol/g per min (n=17)] (P<0.01) but no difference was seen between those with bile acid malabsorption (n=18) versus diarrhoea with a normal SeHCAT test (n=23). The SeHCAT values and 7alpha-hydroxy-4-cholesten-3-one were inversely correlated. CONCLUSIONS: The data do not support bile acid malabsorption being due to a reduced active bile acid uptake capacity in the terminal ileum.

Effects of pretreatment with a xanthine oxidase inhibitor on free radical levels during carotid endarterectomy.

OBJECTIVE: Free radicals contribute to the tissue damage caused by ischaemia-reperfusion. The aim of the present study was to investigate whether preoperative antioxidant therapy (allopurinol) affects free radical levels in cerebral venous blood in connection with surgery for carotid artery stenosis. MATERIALS AND METHODS: Twenty-five patients were randomised into the study. Thirteen were controls and 12 were pretreated with allopurinol the day before surgery. Before, during and after surgery, blood samples were drawn from the ipsilateral jugular vein. Radical levels were measured using the spin trap technique ex vivo using OXANOH as the spin trap. Multivariate statistics were used with Principal Component Analysis and Partial Least Square regression analysis. RESULTS: Radical levels increased with diabetes, high leukocyte count, high creatinine and a high degree of contralateral stenosis. Radical levels decreased with high age, blood pressure, collateral circulation as well as operation for left-side carotid artery stenosis. After pretreatment with allopurinol, several of the relationships noted in the control group were eliminated, i.e. leukocyte count, side of operation, Betapred pretreatment and collateral circulation. CONCLUSIONS: Radical levels can be determined in connection with surgery for carotid artery stenosis using an ex vivo spin trap method. With preoperative antioxidant therapy the relationships between enhanced radical levels and clinical data, as seen in control subjects, disappeared. This might indicate a beneficial effect of preoperative pretreatment with antioxidants.

Enhanced post-ischaemic recovery in rabbit kidney after pretreatment with an indeno-indole compound and ascorbate monitored in vivo by 31P magnetic resonance spectroscopy.

OBJECTIVE: To investigate whether combined pretreatment with lipid- and water-soluble antioxidants gave better restoration of energy phosphates after ischaemia-reperfusion of rabbit kidneys than single pretreatment with a lipid-soluble antioxidant. MATERIAL AND METHODS: Thirteen New Zealand white rabbits were used for the study. Changes in energy phosphates were measured in vivo using volume-selective 31P magnetic resonance spectroscopy. The indeno-indole compound H290/51 was chosen as a lipid-soluble antioxidant and ascorbate as a water-soluble antioxidant. RESULTS: The combined pretreatment led to significantly better restoration of the beta-adenosine triphosphate:inorganic phosphate ratio after 60 min of ischaemia and 120 min of reperfusion compared with the single pretreatment. Analyses of blood pressure and blood gas changes showed that the beneficial effect of combined pretreatment was not caused by a better general condition of the animals in that group but by a direct effect on the kidneys. CONCLUSIONS: Combined pretreatment with lipid- and water-soluble antioxidants leads to better restoration of energy phosphates in rabbit kidneys subjected to ischaemia-reperfusion compared with single pretreatment with a lipid-soluble antioxidant.