Relationship between cellular ATP content and cellular functions of primary cultured rat hepatocytes in hypoxia

The importance of oxygen in maintaining the functional integrity of hepatocytes has been well established in a variety of experimental models, such as in vivo , perfused liver and isolated hepatocytes. However, one of the shortcomings of these systems is their short life span. Therefore, we have examined the effects of long-term hypoxia on cellular adenine nucleotide content and cellular functions, such as albumin production, urea production and DNA synthesis, in adult rat hepatocytes in primary culture. Hepatocytes were cultured at a density of 11 × 10⁴ and 5 × 10⁴ cells/0.18 mL per cm² for the study of albumin and urea production and DNA synthesis, respectively, at various oxygen tensions (20, 12, 8 and 5%) for 24 h. Cellular ATP content in cultured hepatocytes in hypoxia gradually declined, corresponding to the decrease in oxygen tension, and the cellular ATP level at 5% oxygen was approximately 20% of that at 20% oxygen. Albumin production also decreased in parallel with the decrease in cellular ATP content in cultured hepatocytes in hypoxia. However, even when cellular ATP content gradually declined corresponding with the decrease in oxygen tension in cultured hepatocytes in hypoxia, such as at 8 or 5% oxygen, urea production remained at a high level; in contrast, DNA synthesis was completely suppressed. These results suggest that the cellular ATP content decreases in cultured hepatocytes during long-term hypoxia in relation to oxygen tension and that the relationship between decreased ATP levels and liver function in cultured hepatocytes during hypoxia differs for albumin production, urea production and DNA synthesis.     

Intravenous glycerol therapy should not be used in patients with unrecognized fructose-1,6-bisphosphatase deficiency

BACKGROUND: In Asian countries, glycerol solution that contains fructose (5%) is often used for management of brain edema. However, glycerol and fructose may cause severe hypoglycemia and metabolic acidosis in patients with fructose-1,6-bisphosphatase (FBPase) deficiency, even under stable conditions. The aim of the present study was to determine whether glycerol solution was used for brain edema during acute metabolic decompensation of hypoglycemia and metabolic acidosis in patients with unrecognized FBPase deficiency in Japan and to examine a long-term prognosis of the patients who had this kind of severe metabolic decompensation with or without glycerol therapy. METHODS: A retrospective study of 20 children with FBPase deficiency was conducted, based on their medical records. RESULTS: Six of the 20 children were given glycerol solution for the presence or possibility of brain edema during acute metabolic decompensation of hypoglycemia and metabolic acidosis; two of the six patients administered with glycerol were given dialysis. In four patients treated with glycerol alone without dialysis, two had no brain edema before glycerol administration but it developed later after the administration. These four patients treated with glycerol alone died or developed severe neurological complications. Fourteen patients who were not treated with glycerol solution had no brain edema and showed good prognosis. CONCLUSIONS: Glycerol solution, which contains fructose in Asian countries including Japan, should not be used as an osmotic agent for treatment of brain edema in patients who have hypoglycemia and retention-type metabolic acidosis, until FBPase deficiency is ruled out by measuring blood concentration of lactate.     

Morphological comparison and functional reconstitution of rat hepatic parenchymal cells on various matrices

Four types of materials, type I collagen coat (Coat), acid-soluble type I collagen gel (Hardgel), pepsin-treated acid-soluble type I collagen gel (Softgel), and an extract of extracellular matrix of the murine Engelbreth-Holm-Swarm sarcoma (Matrigel), were used as matrices to culture rat hepatic parenchymal cells, and their morphological changes and adhesion were compared to the matrices by electron microscopic observations. Hepatic parenchymal cells cultured on Coat and Hardgel were extended and flattened, whereas cells cultured on Softgel and Matrigel assembled and formed aggregates. Such aggregates consisted of several hepatic parenchymal cells, with a recognizable bile duct-like alveolus on the inside. Morphologically, the aggregates were more spherical on Matrigel and oval shaped on Softgel. Microvilli of the cell surface were parallel to the matrix on Matrigel, but invaded into the gel on Softgel. Subsequently, investigation into how these morphological features affected the liver-specific functions, including secretion of albumin and induction of P450 by 3-methylcholanthrene, demonstrated that a high level of liver function was maintained in a long-term culture in hepatic parenchymal cells on Softgel. These results suggest that hepatic parenchymal cell interactions were stronger with Softgel than with Matrigel, and that Softgel appears to closely mimic the in vivo environment.     

Significance of Ventricular Pacing Site in Manifest Entrainment During Orthodromic Atrioventricular Reentrant Tachycardia with Left-Sided Accessory Pathway

We examined entrainment by ventricular pacing in six patients during orthodromic atrioventricular reentrant tachycardia (AVRT) utilizing a left-sided lateral accessory pathway. Constant fusion and progressive fusion were demonstrated in all patients by left ventricular pacing during tachycardia, but in none of the patients by right ventricular pacing. When left ventricular pacing was performed during AVRT, the antidromic wave front from the pacing impulse (n) collided with the orthodromic wave front of the previous pacing beat (n - 1) within the ventricle, therefore, constant fusion and progressive fusion were demonstrated in the surface electrocardiographic QRS complexes. On the other hand, when right ventricular pacing was performed during orthodromic AVRT, the antidromic wave front from the pacing impulse (n) collided with the orthodromic wave front of the previous paced beat (n - 1) within the normal atrioventricular pathway, and constant fusion and progressive fusion were therefore not demonstrated. These phenomena were explained by the relationship of the ventricular pacing site and the reentrant circuit. This study demonstrates the importance of the pacing site in manifest entrainment of orthodromic AVRT during ventricular pacing.     

Efficacy of hypothermic perfusion using University of Wisconsin solution in extended hepatectomy with hepatic inflow occlusion in a canine model

This study was designed to elucidate the efficacy of University of Wisconsin (UW) solution for preventing liver injury, when used as a hypothermic perfusate infused into the systemic circulation during extended hepatectomy with hepatic inflow occlusion. Adult mongrel dogs (9.5–17.5 kg, n= 14) were subjected to 75% hepatectomy under 60 min hepatic inflow occlusion. The animals were divided into two groups. The UW group (n= 7) underwent hypothermic perfusion using 4°C UW solution (core temperature of the liver: 12.3±0.2°C). The control group designated as the Ringer's lactate (LR) group (n= 7) underwent hypothermic perfusion using 4°C LR solution. The perfusate was introduced into the systemic circulation via the hepatic vein. Blood from the hepatic vein was sampled, and alanine amino-transferase, purine nucleoside phosphorylase activities and the ammonia concentration were measured. The 7 day survival rate was higher in the UW group than in the LR group. The parameters of liver function were less significantly altered in the UW group than in the LR group. The plasma ammonia concentration was significantly (P<0.05) lower 6h after reperfusion in the UW group than in the LR group. A small volume of hypothermic perfusion of the liver using UW solution was safe if it returned to systemic circulation. Hypothermic perfusion of the liver using UW solution may be effective for preventing hepatic tissue injury during extended hepatectomy with hepatic vascular occlusion.     

Visualization of palisade veins in esophageal varices by endoscopic color Doppler ultrasonography

Background: Endoscopic color Doppler ultrasonography (ECDUS) is a useful modality for obtaining color flow images of esophageal varices. Levovist is a microbubble echo‐enhancing agent that improves Doppler ultrasound examination. This study is designed to evaluate the usefulness of ECDUS using Levovist in diagnosing palisade veins of esophageal varices. Methods: The study involved 67 patients with esophageal varices using ECDUS. All 67 patients received Levovist intravenously at a concentration of 300 mg/mL. A 7.5‐mL dose of the contrast agent was injected at a slow infusion rate of 1 mL/min. We compared vessel images detected with precontrast with those detected by enhanced ECDUS. Results: Color flow images of palisade veins were obtained in 16 (23.9%) of the 67 patients with precontrast ECDUS. Vessel images of palisade veins were detected in 15 of 61 F2 type varices (24.6%) and in one of six F3 varices (16.7%). The color flows of these vessels showed a continuous wave on fast‐Fourier transform analysis. Sixteen palisade veins had velocities in the 3.3 cm/s?11.6 cm/s range. Color flow images of palisade veins were obtained in 27 (40.3%) of the 67 cases by enhanced ECDUS using Levovist. Palisade veins could be delineated after Levovist contrast in 11 patients who could not be detected on precontrast ECDUS. After Levovist contrast, color flow images detected with precontrast ECDUS were enhanced in all patients. Conclusion: Endoscopic color Doppler ultrasonography with Levovist contrast can improve the diagnostic quality of the palisade veins in esophageal varices.