A residual hepatic vein to left atrial communication may result in progressive cyanosis after the Fontan procedure. This problem has usually been treated surgically by ligation or re-inclusion of the residual hepatic vein in the Fontan circulation. Previous attempts at transcatheter closure of such veins have been unsuccessful. An Amplatzer septal occluder was successfully used for transcatheter closure of a post-Fontan hepatic vein to pulmonary venous atrium fistula in an 8 year old boy. (+info)
(2/498) Doppler sonographic enhancement of hepatic hemangiomas and hepatocellular carcinomas after perflenapent emulsion: preliminary study.
Ultrasonographic microbubble contrast agents improve Doppler signals by increasing blood backscatter. We retrospectively reviewed our experience with perflenapent (EchoGen), an emulsion of liquid dodecafluoropentane, in the evaluation of 13 patients with focal hepatic lesions (10 hemangiomas and six hepatocellular carcinomas). Perflenapent improved the detection of color Doppler flow signals within the lesions. The hemangiomas showed peripheral nonpulsatile signals and the hepatocellular carcinomas showed more diffuse enhancement with both arterial and venous type signals. This preliminary study suggests that perflenapent administration may aid in the sonographic differentiation of these focal lesions. (+info)
(3/498) Splanchnic glucagon kinetics in exercising alloxan-diabetic dogs.
The purpose of this study was to define the relationship between arterial immunoreactive glucagon (IRG) and IRG that perfuses the liver via the portal vein during exercise in the diabetic state. Dogs underwent surgery >16 days before the experiment, at which time flow probes were implanted in the portal vein and the hepatic artery, and Silastic catheters were inserted in the carotid artery, portal vein, and hepatic vein for sampling. Dogs were made diabetic with alloxan injected intravenously approximately 3 wk before study (AD) or were studied in the nondiabetic state (ND). Each study consisted of a 30-min basal period and a 150-min moderate-exercise period on a treadmill. The findings from these studies indicate that the exercise-induced increment in portal vein IRG can be substantially greater in AD compared with ND, even when arterial and hepatic vein increments are not different. The larger IRG gradient from the portal vein to the systemic circulation in AD dogs is a function of a twofold greater increase in nonhepatic splanchnic IRG release and a fivefold greater hepatic fractional IRG extraction during exercise. In conclusion, during exercise, arterial IRG concentrations greatly underestimate the IRG levels to which the liver is exposed in ND, and this underestimation is considerably greater in dogs with poorly controlled diabetes. (+info)
(4/498) Regional glycerol and free fatty acid metabolism before and after meal ingestion.
We measured splanchnic and leg glycerol [and free fatty acid (FFA)] uptake and release in 11 healthy volunteers before and after meal ingestion to assess whether regional FFA-to-glycerol release ratios mirror systemic release ratios. Basal splanchnic triglyceride release was also assessed. Although basal splanchnic glycerol uptake (111 +/- 18 micromol/min) accounted for most of systemic glycerol rate of appearance (156 +/- 20 micromol/min), leg glycerol uptake was also noted. The basal, systemic FFA-to-glycerol release ratio was less (2.6 +/- 0.2, P < 0.05) than the splanchnic ratio of 6.1 +/- 1.3, and the leg FFA-to-glycerol release ratio under fed conditions was less than the systemic ratio (0.9 +/- 0.1 vs. 1.6 +/- 0.2, respectively, P < 0.05). Basal splanchnic triglyceride production rates were 74 +/- 20 micromol/min, which could produce equimolar amounts of glycerol in the peripheral circulation via lipoprotein lipase action. In summary, 1) regional FFA-to-glycerol release ratios do not mirror systemic ratios, 2) leg glycerol uptake occurs in humans, and 3) splanchnic triglyceride production rates are substantial relative to systemic glycerol appearance. Glycerol appearance rates may not be a quantitative index of whole body lipolysis. (+info)
(5/498) Rapid reversal of the effects of the portal signal under hyperinsulinemic conditions in the conscious dog.
Experiments were performed on two groups of 42-h-fasted conscious dogs (n = 6/group). Somatostatin was given peripherally with insulin (4-fold basal) and glucagon (basal) intraportally. In the first experimental period, glucose was infused peripherally to double the hepatic glucose load (HGL) in both groups. In the second experimental period, glucose (21.8 micromol. kg-1. min-1) was infused intraportally and the peripheral glucose infusion rate (PeGIR) was reduced to maintain the precreating HGL in the portal signal (PO) group, whereas saline was given intraportally in the control (CON) group and PeGIR was not changed. In the third period, the portal glucose infusion was stopped in the PO group and PeGIR was increased to sustain HGL. PeGIR was continued in the CON group. The glucose loads to the liver did not differ in the CON and PO groups. Net hepatic glucose uptake was 9.6 +/- 2.5, 11.6 +/- 2.6, and 15.5 +/- 3.2 vs. 10.8 +/- 1.8, 23.7 +/- 3.0, and 15.5 +/- 1.1 micromol. kg-1. min-1, and nonhepatic glucose uptake (non-HGU) was 29.8 +/- 1.1, 40.1 +/- 4.5, and 49.5 +/- 4.0 vs. 26.6 +/- 4.3, 23.2 +/- 4.0, and 40.4 +/- 3.1 micromol. kg-1. min-1 in the CON and PO groups during the three periods, respectively. Cessation of the portal signal shifted NHGU and non-HGU to rates similar to those evident in the CON group within 10 min. These results indicate that even under hyperinsulinemic conditions the effects of the portal signal on hepatic and peripheral glucose uptake are rapidly reversible. (+info)
(6/498) Splanchnic and leg substrate exchange after ingestion of a natural mixed meal in humans.
The disposal of a mixed meal was examined in 11 male subjects by multiple (splanchnic and femoral) catheterization combined with double-isotope technique (intravenous [2-3H]glucose plus oral U-[14C]starch). Glucose kinetics and organ substrate balance were measured basally and for 5 h after eating pizza (600 kcal) containing carbohydrates 75 g as starch, proteins 37 g, and lipids 17 g. The portal appearance of ingested carbohydrate was maximal (1.0 mmol/min) between 30 and 60 min after the meal and gradually declined thereafter, but was still incomplete at 300 min (0.46+/-0.08 mmol/min). The total amount of glucose absorbed by the gut over the 5 h of the study was 247+/-26 mmol (45+/-6 g), corresponding to 60+/-6% of the ingested starch. Net splanchnic glucose balance (-6.7+/-0.5 micromol x kg(-1) x min(-1), basal) rose by 250-300% between 30 and 60 min and then returned to baseline. Hepatic glucose production (HGP) was suppressed slightly and only tardily in response to meal ingestion (approximately 30% between 120 and 300 min). Splanchnic glucose uptake (3.7+/-0.6 micromol x kg(-1) x min(-1), basal) peaked to 9.8+/-2.0 micromol x kg(-1) x min(-1) (P<0.001) at 120 min and then returned slowly to baseline. Leg glucose uptake (34+/-5 micromol x leg(-1) x min(-1), basal) rose to 151+/-29 micromol x leg(-1) x min(-1) at 30 min (P<0.001) and remained above baseline until the end of the study, despite no increase in leg blood flow. The total amount of glucose taken up by the splanchnic area and total muscle mass was 161+/-16 mmol (29+/-3 g) and 128 mmol (23 g), respectively, which represent 39 and 30% of the ingested starch. Arterial blood lactate increased by 30% after meal ingestion. Net splanchnic lactate balance switched from a basal net uptake (3.2+/-0.6 micromol kg(-1) x min(-1) to a net output between 60 and 120 min and tended to zero thereafter. Leg lactate release (25+/-11 micromol x leg(-1) x min(-1), basal) drastically decreased postprandially. Arterial concentration of both branched-chain amino acids (BCAA) and non-branched-chain amino acids (N-BCAA) increased significantly after meal ingestion (P<0.001). The splanchnic area switched from a basal net amino acid uptake (31+/-16 and 92+/-48 micromol/min for BCAA and N-BCAA, respectively) to a net amino acid release postprandially. The net splanchnic amino acid release over 5 h was 11.3+/-4.2 mmol for BCAA and 37.8+/-9.7 mmol for N-BCAA. Basally, the net leg balance of BCAA was neutral (-3+/-5 micromol x leg(-1) x min(-1)), whereas that of N-BCAA indicated a net release (54+/-14 micromol x leg(-1) x min(-1)). After meal ingestion, there was a net leg uptake of BCAA (20+/-6 micromol x leg(-1) x min(-1)), whereas leg release of N-BCAA decreased by 50%. It is concluded that in human subjects, 1) the absorption of a natural mixed meal is still incomplete at 5 h after ingestion; 2) HGP is only marginally and tardily inhibited; 3) splanchnic and peripheral tissues contribute to the disposal of meal carbohydrate to approximately the same extent; 4) the splanchnic area transfers >30% of the ingested proteins to the systemic circulation; and 5) after meal ingestion, skeletal muscle takes up BCAA to replenish muscle protein stores. (+info)
(7/498) The terminal hepatic microcirculation in the rat.
The hepatic microcirculation was observed microscopically in the transilluminated liver of the rat. The portal and hepatic venous microvessels were classified into four orders according to their branching hierarchy, and the hepatic sinusoids into branching, direct and interconnecting types according to their topographic arrangements. The diameters of the various orders of microvessels and types of sinusoids were measured by serial photomicrography, and the velocity of the erythrocytes in these various microvessels and sinusoids by the dual-slit photometric technique. The microvascular volume flows were calculated from these data. In both portal and hepatic venous systems, the erythrocyte velocity and the volume flow significantly decreased in successive orders of the microvessels in apparent relation to the cross-sectional areas. The diameters of the three types of sinusoids did not significantly differ, but the velocity of the erythrocytes in the direct sinusoid was significantly faster than that in the branching sinusoid while that in the inter-connecting sinusoid fluctuated widely. (+info)
(8/498) Arterial KIC as marker of liver and muscle intracellular leucine pools in healthy and type 1 diabetic humans.
In human protein turnover studies with isotopically labeled leucine (Leu) as a tracer, plasma ketoisocaproate (KIC) enrichment is extensively used as a surrogate measure of intracellular leucine enrichment. To test how accurately arterial ketoisocaproate (A-KIC) represents leucine isotopic enrichment in the hepatic (HV) and femoral veins (FV), which drain liver and muscle beds, we measured Leu and KIC enrichments in samples collected from HV, FV, and femoral artery (A) in 24 control and 6 type I diabetic subjects after a primed, continuous infusion of L-[1-(13)C,(15)N]-Leu. Studies were performed during insulin deprivation or insulin replacement in the diabetic group, whereas the effect of normal saline or three different doses of insulin infusion (0.25, 0.50, and 1 mU. kg(-1). min(-1)) were assessed in healthy controls. The ratios of baseline isotopic enrichments of A-KIC to HV Leu and FV Leu were 0.93 +/- 0.01 and 0.94 +/- 0.02, respectively, in normal subjects and 1.07 +/- 0.04 and 1.05 +/- 0.03, respectively, in diabetic subjects (P < 0.01, diabetic vs. normal subjects). Insulin did not change A-KIC-to-HV Leu ratios in either group, but the A-KIC-to-FV Leu ratio decreased during insulin infusion in normal subjects (P < 0.05). In conclusion, A-KIC represents a reliable surrogate measure of HV Leu enrichment at different levels of circulating insulin in humans. The present data support the use of A-KIC as a surrogate precursor pool for hepatic protein synthesis. (+info)