Selective culture method for hepatocyte-like cells differentiated from human induced pluripotent stem cells

This study aimed to establish culture conditions which are able to give the differentiation of induced pluripotent (iPS) cells to hepatocytes. To this end, we examined the usefulness of a culture medium containing the components involved in the intermediary metabolism in the liver. More specifically, we examined the effect of the "modified L-15 medium" containing galactose, phenylalanine and ornitine, but deprived of glucose, tyrosine, arginine and pyruvic acid. The medium was altered according to changes in the expression of enzymes that participate in liver-specific pathways. After 25 days of differentiation, the differentiated cells expressed hepatocyte markers and drug-metabolizing enzymes. These expression levels were increased using modified L-15 medium. The survival of human fetal liver cells and the death of human fibroblasts were observed during culture in modified L-15 medium. Most of the cells that differentiated from human iPS cells using modified L-15 medium were stained by anti-human albumin antibody. These results suggest that iPS cells can be converted to high purity-differentiated hepatocytes by cultivating them in modified L-15 medium.

An efficient method for differentiation of human induced pluripotent stem cells into hepatocyte-like cells retaining drug metabolizing activity

The use of human induced pluripotent stem (iPS) cells would be of great value for a variety of applications involving drug development studies. Several reports have been published on the differentiation of human iPS cells into hepatocyte-like cells; however, the cells were insufficient for application in drug metabolism studies. In this study, we aimed to establish effective methods for differentiation of human iPS cells into hepatocytes. Two human iPS cell lines were differentiated by addition of activin A, dimethyl sulfoxide, hepatocyte growth factor, oncostatin M, and dexamethasone. The differentiated cells expressed hepatocyte markers and drug-metabolizing enzymes, revealing that the human iPS cells were differentiated into hepatocyte-like cells. Expression of CYP3A4 and UGT1A1 mRNAs increased with treatment with typical inducers of the enzymes, and the response of the cells against the inducers was similar to that of human hepatocytes. Furthermore, the drug-metabolizing activity of CYP3A4, as monitored by testosterone 6β-hydroxylase activity, was elevated by these inducers. In conclusion, we established methods for differentiation of hepatocyte-like cells expressing drug metabolizing activity from human iPS cells. The hepatocyte-like cells derived from human iPS cells will be useful for drug metabolism studies.

Differentiation of human induced pluripotent stem cells into functional enterocyte-like cells using a simple method

  Human induced pluripotent stem (iPS) cells were differentiated into the endoderm using activin A and were then treated with fibroblast growth factor 2 (FGF2) for differentiation into intestinal stem cell-like cells. These immature cells were then differentiated into enterocyte-like cells using epidermal growth factor (EGF) in 2% fetal bovine serum (FBS). At the early stage of differentiation, mRNA expression of caudal type homeobox 2 (CDX2), a major transcription factor related to intestinal development and differentiation, and leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5), an intestinal stem cell marker, was markedly increased by treatment with FGF2. When cells were cultured in medium containing EGF and a low concentration of FBS, mRNAs of specific markers of intestinal epithelial cells, including sucrase-isomaltase, the intestinal oligopeptide transporter SLC15A1/peptide transporter 1 (PEPT1), and the major metabolizing enzyme CYP3A4, were expressed. In addition, sucrase-isomaltase protein expression and uptake of β-Ala-Lys-N-7-amino-4-methylcoumarin-3-acetic acid (β-Ala-Lys-AMCA), a fluorescence-labeled substrate of the oligopeptide transporter, were detected. These results demonstrate a simple and direct method for differentiating human iPS cells into functional enterocyte-like cells.

Visceral fat accumulation is a significant risk factor for white matter lesions in Japanese type 2 diabetic patients

BACKGROUND

The presence of white matter lesions (WML) is an important prognostic factor for the development of stroke. The elevated visceral fat accumulation (VFA) has been reported to be closely related to the development of atherosclerosis. This preliminary study was therefore designed to test the hypothesis that the presence of WML correlates with VFA and insulin resistance in type 2 diabetic patients not receiving insulin treatment.

MATERIAL AND METHODS

Based on brain magnetic resonance imaging (MRI), 95 type 2 diabetic patients were divided into two groups: WML-positive group (aged 59 +/- 7 years, mean +/- SD n = 37) and WML-negative group (aged 58 +/- 5, years, n = 58). The level of blood glucose was assessed by fasting plasma glucose (FPG), fasting immunoreactive insulin, homeostasis model assessment (HOMA) index, and haemoglobin A1c. The fat distribution was evaluated by measuring the visceral fat accumulation by abdominal computerized tomography at the umbilical level.

RESULTS

The body mass index was higher in the WML-positive group than in the WML-negative group (P < 0.005). Plasma levels of triglycerides were higher while high-density lipoprotein cholesterol was lower in the WML-positive group than in the WML-negative group (P < 0.05 and P < 0.01, respectively). FPG (P < 0.01), insulin concentrations (P < 0.0001), HOMA index (P < 0.0001) and VFA (<0.0001) levels were higher in the WML-positive group than in the WML-negative group. Multivariate logistic analysis revealed that WML was independently predicted by the high VFA and insulin resistance (P < 0.001, P < 0.0001, respectively).

CONCLUSIONS

The results of this preliminary study indicate that the presence of WML was associated with the high VFA and insulin resistance in Japanese patients with type 2 diabetes mellitus. Further larger cohort studies are warranted to confirm these findings.

Pioglitazone shift circadian rhythm of blood pressure from non-dipper to dipper type in type 2 diabetes mellitus

BACKGROUND

Insulin resistance significantly correlated with a non-dipper type of essential hypertension. Thiazolidinediones (TZD), oral hypoglycaemic agents that act as insulin sensitizers, have been demonstrated in multiple in vivo and in vitro studies to possess antihypertensive properties. This study examined the efficacy of TZD therapy with pioglitazone at transforming the circadian rhythms of blood pressure from a non-dipper to a dipper type.

MATERIALS

We examined 31 patients with type 2 diabetes mellitus during both a baseline period and a period of treatment with pioglitazone. Patients received 15 mg day(-1) pioglitazone for four weeks and 30 mg day(-1) for 12 weeks. Twenty-four hour ambulatory blood pressure monitoring (ABPM) and laboratory data (blood tests for cardiovascular risk factors) were obtained at the beginning and end of the study.

RESULTS

In non-dippers (n = 16), but not dippers (n = 15), we observed a significant interaction between pioglitazone therapy and nocturnal falls in systolic and diastolic blood pressure. This examination indicated that the magnitude of the nocturnal blood pressure fall was affected by pioglitazone therapy. In non-dippers, but not dippers, a significant correlation was observed between the percent decrease in nocturnal BP and the homeostasis model assessment (HOMA) index (r = 0.774, P = 0.0007).

CONCLUSIONS

The present study demonstrated that pioglitazone can restore the nocturnal BP declines in parallel to reductions in the HOMA index, suggesting that insulin resistance may play an important role in the genesis of circadian BP rhythms. TZD-based treatment may thus have the additional therapeutic advantage of reducing the risk of cardiovascular complications by transforming the circadian rhythm of BP.

Effect of Lactobacillus casei on the Absorption of Nifedipine from Rat Small Intestine

Lactobacillus casei Shirota strain (L. casei) has a modulating effect on the production of cytokines, which often play important roles in drug metabolism, in the inflamed intestinal mucosa. We evaluated the effect of L. casei administered orally in advance for 4 weeks on the absorption of nifedipine from the rat small intestine. The maximum concentration of nifedipine in plasma after administration into the intestinal loop (0.8 mg/kg) was significantly higher in L. casei-treated rats (3.26 microg/mL) than in those untreated rats (2.33 microg/mL) by 40%. Accordingly, the bioavailability of nifedipine was tended to be higher in the former, while the effect of L. casei on the disposition of intravenously administered nifedipine was negligible. We also found that the availability of nifedipine for the passage through the intestinal mucosa was significantly increased in L. casei-treated rats from the single-pass intestinal perfusion experiments. Therefore, it is likely that the exposure to nifedipine after its administration into rat intestine was increased by oral ingestion of L. casei due to an increase in absorption by increased intestinal availability (decreased metabolic extraction) during passage through the intestinal mucosa. This study has suggested that L. casei has some effect on the metabolic activity in the intestinal mucosa, though it seems to be only mild.

Absorption and Metabolic Extraction of Diltiazem from the Perfused Rat Small Intestine

The metabolic extraction of diltiazem was examined in conjunction with its absorption, using rat small intestine perfused in situ by the single-pass method, to clarify its intestinal metabolism. This is a topic of increasing interest which has not been fully clarified, particularly as far as the extent of metabolic extraction and the enzymes involved (cytochrome P450 (CYP) 3A and/or others) are concerned. The intestinal availability (Fi) of diltiazem was evaluated at steady-state by dividing the fraction absorbed into the mesenteric venous blood (Fa,b) by the fraction that disappeared from the intestinal lumen (Fa). The Fi of diltiazem (0.05 mM) was 0.126 and, hence, the extraction ratio (Ei=1-Fi) was 0.874, indicating that diltiazem undergoes extensive first-pass metabolism during its passage through the intestinal mucosa. The Ei was unchanged when the concentration was increased to 0.5 mM, suggesting that metabolism is linear over this concentration range. Thereafter, Ei decreased with concentration, demonstrating saturable metabolism, and reached an insignificant level at the highest concentrations of 30 and 50 mM. The decrease in Ei, or increase in Fi, was brought about by an increase in Fa,b (from about 0.02 to about 0.05) in the concentration range up to 10 mM and by a decrease in Fa (from about 0.15 to about 0.05) at concentrations higher than that. These results suggest that the extraction observed at the lower concentrations is almost solely attributable to metabolic extraction of a saturable nature. However, ketoconazole and cyclosporin A, which are specific CYP3A inhibitors, inhibited the metabolic extraction of diltiazem (0.05 mM) by only about 20% at the concentration (40 microM) at which they inhibited CYP3A almost completely, suggesting that the contribution of CYP3A to intestinal diltiazem metabolism is not marked. Thus, the present study demonstrates that diltiazem undergoes extensive first-pass metabolism in the rat small intestine, although the contribution of CYP3A seems to be relatively minor.

Metabolic Extraction of Nifedipine during Absorption from the Rat Small Intestine

Nifedipine is one of drugs that have been suggested to undergo significant first-pass metabolism by cytochrome P450 (CYP) 3A in the intestine, based mainly on pharmacokinetic analyses of in vivo observations. To further substantiate this suggestion, we examined the metabolic extraction of nifedipine from the rat small intestine, using intestine perfused in situ by a single-pass technique and microsomes in vitro. When the intestinal lumen was perfused with nifedipine solution (30 microM) at the flow rate of 0.15 mL/min and steady-state was achieved, the fraction that disappeared from the intestinal lumen (F(a)) and the fraction absorbed into the mesenteric venous blood (F(a,b)) was 0.26 and 0.13, respectively. Thus, F(a,b) was 50% smaller than F(a), indicating a significant extraction of nifedipine during passage through the intestinal mucosa. When ketoconazole (40 microM), a specific inhibitor of CYP3A, was added to the perfusion solution, F(a,b) was increased to a level comparable with F(a), while F(a) remained unchanged, suggesting the complete inhibition of metabolic extraction by CYP3A. A similar result was obtained for cyclosporin A (40 microM), another specific CYP3A inhibitor. In intestinal microsomes, the metabolic degradation of nifedipine (1 microM) was almost completely inhibited by ketoconazole (10 microM) and cyclosporin A (10 microM), consistent with the results in the perfused intestine. It was also found in intestinal microsomes that anti-rat CYP3A2 antibody can inhibit nifedipine metabolism completely. Thus, the present study demonstrates that nifedipine undergoes significant extraction during passage through the intestinal mucosa, and provides substantial evidence that CYP3A2 is responsible for that.

Suppression of cesium-induced ventricular tachyarrhythmias by atrial natriuretic peptide in rabbits

BACKGROUND

Intravenous injection of cesium chloride (Cs) causes ventricular tachyarrhythmias in rabbits. We investigated whether these tachyarrhythmias were caused by increased pressure load and whether they could be suppressed by atrial natriuretic peptide (ANP).

METHODS AND RESULTS

Cs was injected in a bolus dose (1.5 mmol/kg), which was repeated 20 minutes later. Rabbits were then divided into 3 groups: control, ANP-treated, and hydralazine-treated groups. ANP or hydralazine was administered between the first and second Cs injections. The experiments were performed during intrinsic sinus rhythm (protocol A) or during ventricular pacing (protocol B). In protocol A, the second injection of Cs in the control group induced early afterdepolarizations and ventricular tachycardia, which were preceded by a marked increase in left ventricular end-diastolic pressure (LVEDP). Both ANP and hydralazine significantly suppressed Cs-induced increase in LVEDP. The arrhythmia score after the second injection of Cs was significantly lower in the ANP-treated and hydralazine-treated group compared with the control group (P < .005 and P < .05, respectively). In protocol B, the duration of left ventricular monophasic action potential and early afterdepolarization amplitude before and/or after the injections of Cs did not differ significantly between control and ANP-treated groups.

CONCLUSIONS

Our results suggest that increased pressure load may play a role in the arrhythmogenic effect of Cs. The protective effect of ANP against Cs-induced ventricular tachycardia may be explained in part by a reduction in pressure overload. However, this effect might also be explained by the diverse action of ANP on the cardiovascular system.

Preceding stimulus frequency-dependent potentiation of the postrest shortening of the action potential duration in rabbits

Action potential duration (APD) in rabbit ventricular myocardium shortens after a rest period (postrest shortening). However, the effects of preceding stimulus frequency on the postrest shortening have not been elucidated. We recorded transmembrane action potentials (TAPs) and monophasic action potentials (MAPs) from the rabbit ventricle. In in vitro experiments. repetitive regular stimuli (S1) at cycle lengths ranging between 500 to 3000 ms were followed by a single extrastimulus (S2) at a coupling interval of 5000 ms. A decrease in S1S1 interval resulted in a progressive shortening of the duration of TAP (TAPD) elicited by S2 (S2-TAPD), which was potentiated by increasing extracellular calcium concentration ([Ca2+]o) or application of ouabain and was inhibited by lowering [Ca2+]o or verapamil. Application of ryanodine was most effective in lengthening S2-TAPD following a short S1S1 interval. 4-aminopyridine and E4031 caused marked lengthening of S2-TAPD when S1S1 was long. However, the lengthening effect was attenuated and disappeared with a shorter S1S1 interval. In in vivo experiments, regular ventricular pacing (S1) at cycle lengths ranging between 250 to 1000 ms was followed by a single extrastimulus (S2) with a coupling interval (S1S2) of 1500 ms. A decrease in the S1S1 interval also resulted in progressive shortening of the duration of MAP elicited by S2. Our results indicate that the postrest shortening is potentiated by an increase in the preceding stimulus frequency in the rabbit ventricle, in which the function of sarcoplasmic reticulum may play a significant role.

Radiofrequency catheter ablation from the left sinus of Valsalva in a patient with idiopathic ventricular tachycardia

We report the case of a 54-year-old woman with idiopathic VT originating in the left ventricular outflow tract. She initially presented with palpitations and light-headedness. The morphology of the PVCs exhibited an inferior axis and tall R waves were noted in all the precordial leads. Spontaneous PVCs were transiently terminated by an intravenous injection of adenosine triphosphate. Radiofrequency catheter ablation from the left sinus of Valsalva successfully abolished the PVCs and the VT.

High plasma cardiac natriuretic peptides associated with enhanced cyclic guanosine monophosphate production in preascitic cirrhosis

BACKGROUND/AIMS

The initial abnormalities of renal sodium handling in cirrhosis remain unclear. The aim of this study was to characterize sodium metabolism in preascitic cirrhosis.

METHODS

Ten patients with preascitic cirrhosis and ten controls were studied. All subjects ate a diet providing 120 mmol sodium during an equilibration period lasting 5 days and the study day. On the study day, after remaining in bed, plasma levels of atrial natriuretic peptide, brain natriuretic peptide, renin activity, aldosterone, noradrenaline, and cyclic guanosine monophosphate were measured at 7 am. Thereafter, they were instructed to maintain an upright posture until dinner and the measurements were repeated at 9 am and 6 pm. After having dinner, all subjects were asked to remain in bed and the measurements were repeated at 11 pm. To measure renal sodium and cyclic guanosine monophosphate excretion, 24-h urine collections were performed, starting from 7 pm on the day before the experimental day.

RESULTS

Plasma levels of atrial natriuretic peptide, brain natriuretic peptide and cyclic guanosine monophosphate in patients with preascitic cirrhosis were significantly elevated compared with those in controls at every sampling time (p=0.03 or less, p= 0.04 or less, and p=0.01 or less). In contrast, plasma renin activities at every sampling time were significantly lower in patients than in controls (p= 0.04 or less). Plasma aldosterone and noradrenaline levels were not significantly different at every sampling time in the two groups. No significant differences in daily renal sodium excretion were found. However, urinary cyclic guanosine monophosphate excretion was significantly higher in patients than in controls (p<0.01).

CONCLUSIONS

The initial abnormalities of sodium metabolism in cirrhosis might be characterized by blunted renal responsiveness to natriuretic peptides. The results of the study also provide indirect evidence that the impairment is mainly located at postreceptor levels of signal transduction pathway to the peptides, if the activation of antinatriuretic factors other than renin-angiotensin or sympathoadrenergic systems does not play a role.

Effect of constant and intermittent vagal stimulation on the heart rate and heart rate variability in rabbits

To examine whether the high-frequency (HF) component of heart rate variability (HRV) reflects fluctuation or tonic level of vagal outflow, we investigated the effects of vagal efferent nerve stimulation (VS) on the heart rate and HRV in anesthetized open-chest rabbit under artificial respiration at a rate of 52 breaths/min (0.86 Hz). A power spectral analysis was performed at baseline and during VS (stimuli at 2 ms, 1-10 V and 5-25 Hz). VS was applied using two different patterns. The first was constant VS; continuous stimulation at graded frequency or voltage to simulate changes in the level of vagal "tone." The second pattern was intermittent VS; stimulation at 0.5 Hz of on-off cycle to simulate fluctuations in vagal efferent activity. The power spectrum at baseline showed a single narrow component at 0.86 Hz, identical to respiration rate. Both the constant and intermittent VS prolonged RR interval. The amplitude of the component at 0.86 Hz remained unaffected by either the constant or intermittent VS, whereas the latter evoked a distinct narrow component at 0.5 Hz, reflecting the on-off cycle of intermittent VS. Our results suggest that the HF component of the power spectrum of HRV measures the magnitude of fluctuations of vagal input associated with respiratory modulation.

Influence of autonomic tone on the filtered QRS duration from signal averaged electrocardiograms in healthy volunteers

We recently reported that signal averaged electrocardiograms (SAECG) measurements possess a circadian rhythm and are closely related to heart rate or heart rate variability in healthy volunteers. This study determines the influence of autonomic tone on the filtered QRS (f-QRS) duration from SAECG by using pharmacologic autonomic blockade and exercise in healthy volunteers. Eleven healthy male volunteers were studied. Three protocols were designed to study the effects of exercise (Ex) under control conditions, beta adrenergic blockade or double blockade. SAECGs and heart rate variability (LF and HF: low and high frequency power, LF/HF ratio) were determined from Holter recordings. Ex significantly decreased the f-QRS duration and HF and significantly increased heart rate and LF/HF. Ex during beta adrenergic blockade significantly increased heart rate and decreased f-QRS duration and HF, but did not change LF/HF. Ex during double blockade did not affect the f-QRS duration, HF, or LF/HF. The changes in f-QRS duration induced during Ex, autonomic blockade, or both were inversely correlated with changes in heart rate and LF/HF and positively correlated with changes in HF. These data suggest that f-QRS duration in healthy subjects is shortened by Ex with increased sympathetic tone or decreased parasympathetic tone or the combination.

Effect of transcatheter arterial chemoembolization on kidney hemodynamics and function in patients with cirrhosis and hepatocellular carcinoma

BACKGROUND/AIMS

Transcatheter arterial chemoembolization (TACE) may have deleterious effect on the kidney in patients with cirrhosis and hepatocellular carcinoma. The aim of the study was to test this hypothesis.

METHODS

Twenty-four patients with cirrhosis and hepatocellular carcinomas were included. They consisted of 16 patients undergoing a single TACE and eight patients undergoing diagnostic angiography. Doppler ultrasonography was used to measure hepatic artery pulsatility index (HA-PI) and renal artery pulsatility index (RA-PI) before and 1 day and 10 days after the procedure. Similarly, kidney function was assessed by measuring creatinine clearance. In addition, plasma renin activity, noradrenaline, and endothelin-1 were also measured.

RESULTS

In patients receiving diagnostic angiography, no significant changes in HA-PI were observed after the procedure. In contrast, HA-PI increased significantly 1 day after the procedure (19%, p<0.01) in patients undergoing TACE, although it returned to baseline value 10 days after the procedure. In patients undergoing diagnostic angiography, no significant changes in RA-PI were observed after the procedure. Similarly, no detectable changes in RA-PI were noted in patients undergoing TACE. A transient small reduction in creatinine clearance was noted after the procedure in patients undergoing diagnostic angiography (-12%, p<0.05) and in those undergoing TACE (-11%, p<0.05). However, the effect was similar in the two groups (two-way ANOVA, p=0.72). No significant changes in plasma renin activity, noradrenaline, and endothelin-1 were observed after either diagnostic angiography or TACE.

CONCLUSIONS

These results suggest that TACE per se has no deleterious effect on the kidney hemodynamics and function in patients with cirrhosis and hepatocellular carcinoma.

Evaluation of autonomic influences on QT dispersion using the head-up tilt test in healthy subjects

Our objective was to examine the autonomic influence on QT interval dispersion using the head-up tilt test in healthy subjects. RR and QT intervals, heart rate variability, and plasma norepinephrine concentration were measured in the supine position and tilting to 70 degrees for 20 minutes using a footboard support in 15 healthy male volunteers (mean age +/- SD: 28.0 +/- 4.5 years). The rate-corrected QT interval (QTc) was calculated using Bazett's formula, and QT and QTc dispersions were defined as the maximum minus minimum values for the QT and QTc, respectively, from the 12-lead ECG. Spectral analysis of the heart rate variability generated values for the low- and high-frequency powers (LF and HF) and their ratio (LF/HF). Compared with values obtained in the supine position, tilting significantly increased QT (P < 0.05) and QTc dispersion (P < 0.01), the LF/HF ratio (P < 0.0001), and plasma norepinephrine concentration (P < 0.0001), and significantly decreased HF (P < 0.0001). QTc dispersion was positively correlated with the LF/HF ratio and plasma norepinephrine concentration, and negatively correlated with HF. These results suggest that head-up tilt testing increases QT dispersion by increasing sympathetic tone and/or decreasing vagal tone in healthy subjects.

Noninvasive assessment of the cardiac baroreflex: response to downward tilting and comparison with the phenylephrine method

OBJECTIVES

We studied the relation between changes in systolic blood pressure and RR interval during downward tilting in comparison with assessment of baroreflex sensitivity (BRS) measured by the phenylephrine method (Phe-BRS) and with measures of heart rate variability (HRV).

BACKGROUND

The method most extensively used for assessing BRS involves bolus injections of phenylephrine. Several noninvasive methods proposed to assess BRS have not been widely applied in the clinical setting.

METHODS

Sixteen healthy male volunteers were studied (mean age +/- SD 27.5+/-4.6 years). Arterial blood pressure using tonometry and electrocardiogram was simultaneously recorded. After 20 min of 70 degrees upright tilting, the table was returned to supine position at a speed of 3.2 degrees/s. Subsequently, BRS was assessed using an intravenous bolus injection of phenylephrine (2 to 3 microg/kg). Heart rate variability under resting conditions also was analyzed.

RESULTS

In all subjects, a beat to beat systolic blood pressure increase associated with corresponding RR interval lengthening was observed during downward tilting as well as during phenylephrine administration. During both testing procedures, these two variables showed linear correlation, and the slope of regression line during downward tilting (DT-BRS) correlated significantly with Phe-BRS (r = 0.79, p = 0.0003). The DT- and Phe-BRS also correlated significantly with the high frequency component of resting HRV (r = 0.70, p = 0.0023 for DT-BRS; r = 0.58, p = 0.0185 for Phe-BRS).

CONCLUSIONS

We conclude that in a small homogeneous group DT-BRS provided an assessment of reflex cardiac vagal function comparable to that obtained by the phenylephrine method.

Upright posture blunts postprandial splanchnic hyperemia in patients with cirrhosis and portal hypertension

The aim of this study was to compare postprandial hemodynamic changes observed during assumption of the recumbent posture and upright posture in patients with cirrhosis and portal hypertension. Eleven patients with cirrhosis and portal hypertension were studied. Echo-Doppler examinations were performed to measure flow volume in the portal vein (PV), superior mesenteric artery (SMA), and splenic artery (SA) in the fasting condition. Collateral blood flow was indirectly calculated by determining the difference between the sum of SMA, SA, and PV blood flows. After these measurements were done, each patient received a standardized liquid meal and was then randomly assigned to either maintain supine or upright posture, in a crossover design, on 2 different days (recumbent day and upright day). On each study day, the above-mentioned measurements were repeated 30 min and 60 min after the meal. PV blood flow increased significantly after the meal on the recumbent day (P < 0.01) but not on the upright day (P = 0.78). Although there were significant postprandial increases in SMA blood flow on both study days (P < 0.01, P < 0.01), the effect was less pronounced on the upright day than on the recumbent day (P < 0.01). Postprandial SA blood flow showed no change on the recumbent day (P = 0.64), but decreased significantly on the upright day (P < 0.01). The calculated postprandial collateral blood flow increased significantly on the recumbent day (P < 0.05), but showed no change on the upright day (P = 0.53). These results suggest that the upright posture blunts postprandial splanchnic hyperemia in patients with cirrhosis and portal hypertension.

Erythropoietic protoporphyria with fatal liver failure

A 33-year-old woman with a history of photosensitivity, persistent abdominal pain, and liver dysfunction was admitted to our department because of abdominal pain and progression of liver dysfunction. On admission, levels of protoporphyrin and coproporphyrin within erythrocytes were markedly increased. Autofluorescent erythrocytes were also detected, leading to a diagnosis of erythropoietic protoporphyria. A liver biopsy specimen revealed cirrhosis with dark brown granules filling hepatocytes, bile canaliculi, and bile ductules. Transfusion of washed erythrocytes, hemodialysis, and administration of cholestyramine and beta-carotene transiently improved levels of porphyrins and liver function. The patient died of rupture of esophageal varices followed by multiple organ failure. However, the treatments were believed to have extended survival.

Gene mutations of K-ras in gallbladder mucosae and gallbladder carcinoma with an anomalous junction of the pancreaticobiliary duct

OBJECTIVE

In this study, we examined the mutational spectrum of K-ras in cases of gallbladder and gallbladder carcinoma with an anomalous junction of the pancreaticobiliary duct (AJPBD).

METHODS

We examined 35 gallbladders with AJPBD (20 with hyperplasia, 15 with carcinoma) and 38 gallbladders without AJPBD (four normal gallbladders, four with hyperplasia, six with adenoma, 24 with carcinoma). Polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) and direct sequencing were performed to detect mutations in codon 12 or 13 of K-ras.

RESULTS

In the cases with AJPBD, the prevalences of K-ras mutation were 15% (3/20) in hyperplasia, 60% (6/10) in stage I carcinoma, and 100% (5/5) in stage II-IV carcinoma. In the cases without AJPBD, the prevalences of K-ras mutation were 0% (0/4) in normal gallbladder, 0% (0/4) in hyperplasia, 17% (1/6) in adenoma, 7% (1/16) in stage I carcinoma, and 38% (3/8) in stage II-IV carcinoma. Prevalences of K-ras mutation in hyperplasia and carcinoma with AJPBD were greater than those without AJPBD (p < 0.05). The point mutation of GGT to GAT in codon 12 was frequently observed in the cases with AJPBD.

CONCLUSION

These results suggest that the specific K-ras mutation in codon 12 (GGT to GAT) may contribute to the early stage of carcinogenesis in the gallbladder with AJPBD.

Cholecystokinin regulates the invasiveness of human pancreatic cancer cell lines via protein kinase C pathway

We have previously reported that cholecystokinin (CCK) plays an important role in the invasiveness and the production of matrix metalloproteinase-9 (MMP-9) in two human pancreatic cancer cell lines. In this study we investigated the pathway of the invasiveness associated with MMP-9 of those lines regulated by CCK. Two human pancreatic cancer cell lines were treated with CCK-8 alone, CCK-8 and staurosporine, or CCK-8 and indomethacine. The invasiveness and the production of MMP-9 were decreased with staurosporine but not indomethacine. These results suggest that CCK may regulate the invasiveness and the production of MMP-9 via protein kinase C in human pancreatic cancer cell lines.

Effect of meal induced splanchnic arterial vasodilatation on renal arterial haemodynamics in normal subjects and patients with cirrhosis

AIMS

To investigate the relation between changes in splanchnic arterial haemodynamics and renal arterial haemodynamics in controls and patients with cirrhosis.

METHODS

Superior mesenteric artery pulsatility index (SMA-PI) and renal artery pulsatility index (R-PI) were measured using Doppler ultrasonography in 24 controls and 36 patients with cirrhosis. These measurements were repeated 30 minutes after ingestion of a liquid meal or placebo. Sixteen controls and 24 patients received the meal, and eight controls and 12 patients received placebo.

RESULTS

In the fasting condition, patients with cirrhosis had a lower SMA-PI (p<0.01) and a greater R-PI (p<0.01) compared with controls. Placebo ingestion had no effect on splanchnic and renal haemodynamics. In contrast, ingestion of the meal caused a notable reduction in SMA-PI (p<0.01, p<0.01) and an increase in R-PI (p<0.01, p<0.01) in controls and patients with cirrhosis. The meal induced haemodynamic change in SMA-PI was inversely correlated with that in R-PI in controls (t=-0.42, p<0.05) and in patients with cirrhosis (t=-0.29, p<0.05).

CONCLUSIONS

Results support the hypothesis that renal arterial vasoconstriction seen in patients with cirrhosis is one of the kidney's homoeostatic responses to underfilling of the splanchnic arterial circulation.

Sustained left ansae subclaviae stimulation for a 5-hour period inhibits cesium-induced ventricular arrhythmogenesis in rabbits

The acute stimulation of the left ansae subclaviae (LAS) augments cesium chloride (Cs)- induced early afterdepolarizations (EADs) and ventricular arrhythmias. However, the effect of sustained cardiac sympathetic nerve stimulation on Cs-induced arrhythmogenesis remains to be elucidated. Three protocols were used. In protocol A, seven rabbits received continuous LAS stimulation for 5 h (study group), and were then given bolus injections of Cs at 5-min intervals (initial dose 1.5 mmol/kg, followed by repetitive doses 1 mmol/kg). Another eight rabbits received the same dose of Cs after a 5-h observation period without LAS stimulation (control group). The effects of 2 h of LAS stimulation were also assessed in five rabbits of each group. In protocol B, a bolus injection of Cs (1 mmol/kg) was administered during atrial pacing (cycle length: 250 ms) after a 5-h period with (study group, n = 5) or without (control group, n = 5) LAS stimulation, and the amplitude of Cs-induced EADs was measured. In protocol C, a bolus injection of isoproterenol (0.05 mg/kg) was given after a 5-h period with (study group, n = 5) or without (control group, n = 5) LAS stimulation to assess the sensitivity to beta-adrenergic stimulation. In protocol A, the cumulative doses of Cs required for the induction of ventricular tachycardia (VT) and fibrillation (VF) were significantly greater in the study group than in the control group (4.4 +/- 0.1 v 2.8 +/- 0.3 mmol/kg for VT, P<0.05; 5.8 +/- 0.3 v 4.1 +/- 0.4 mmol/kg for VF, P<0.05). However, 2 h of LAS stimulation did not influence the cumulative doses of Cs required for the induction of VT and VF. In protocol B, the amplitude of Cs-induced EADs was significantly lower in the study group than in the control group. In protocol C, the increase in rate-pressure product by isoproterenol was significantly less in study than in control groups (3492 +/- 612 v 6504 +/- 829, P<0.05). These results suggest that sustained LAS stimulation exerts a protective effect against Cs-induced arrhythmogenesis in the rabbit heart, which may be partially explained by desensitization to the beta-adrenergic stimulation.

Portal-hypertensive gastropathy

In the present article we describe updated information concerning the clinical feature of portal-hypertensive gastropathy (PHG), which is characterized by mucosal and submucosal vascular dilatation without inflammation. Although this lesion represents non-variceal bleeding, there is a wide variation of its prevalence. Portal pressure and some humoral factors may play important roles in its pathogenesis. Gastric acid secretory activity is reduced, whereas the gastric mucosal barrier is impaired. With regard to gastric mucosal haemodynamics, whether 'overflow' (i.e. active congestion) or 'stasis' (i.e. passive congestion) cause gastric mucosal hyperaemia is not known. A severe lesion is a potential source of bleeding, while mild lesions are of little clinical significance and endoscopic variceal obliteration aggravates PHG in some patients. In the treatment of PHG, pharmacological (e.g. propranolol), surgical (e.g. portosystemic shunt) and radiological (e.g. transjugular intrahepatic portosystemic shunt) procedures may be useful in preventing bleeding from PHG.

Vagal modulation of ventricular tachyarrhythmias induced by left ansae subclaviae stimulation in rabbits

Previous evidence has shown that vagal nerve activity modulates ventricular arrhythmias in patients and in animal models. However, the effects of direct vagus nerve stimulation on ventricular tachyarrhythmias brought by direct sympathetic nerve stimulation have not been elucidated. In the present study, the effects of electrical stimulation of the left cervical vagus nerve on ventricular tachycardia (VT) which was induced by electrical stimulation of the left ansae subclaviae (LAS) in rabbits were assessed. Monophasic action potentials (MAPs) of the left ventricular endocardium were recorded simultaneously with surface ECG. In 27 rabbits tested, the stimulation of LAS induced VT in 19 rabbits. Polymorphic VT (PVT) was induced in 14 rabbits (PVT group), whereas monomorphic VT (MVT) was induced in 5 rabbits (MVT group). Vagus nerve stimulation during the sympathetically-induced PVT led to a restoration of sinus rhythm in 10 of 14 rabbits, while that during the sympathetically-induced MVT did not restore sinus rhythm in any of the 5 rabbits. Vagus nerve stimulation during the stimulation of LAS, which was of subthreshold intensity for the induction in VT, did not result in an induction of PVT in any of the 14 rabbits in the PVT group, while it induced slow MVT in 3 of 5 rabbits in the MVT group. These results indicate that vagus nerve stimulation preferentially exerts protective antiarrhythmic effects against PVT induced by sympathetic neural stimulation in this model, while it occasionally induces slow MVT under conditions in which sympathetic nerve activity in potentially elevated.

Mechanism of beta-adrenergic receptor upregulation induced by ACE inhibition in cultured neonatal rat cardiac myocytes: roles of bradykinin and protein kinase C

BACKGROUND

Although bradykinin is thought to contribute to the effects of ACE inhibitors on the cardiovascular system, its precise role remains to be elucidated. Evidence suggests that bradykinin might be important in the upregulation of beta-adrenergic receptors (beta-ARs) induced by ACE inhibitors, and the role of bradykinin in this effect has now been investigated with cultured neonatal rat cardiac myocytes.

METHODS AND RESULTS

The density of beta-ARs on the myocyte surface was determined with a binding assay with [3H]CGP-12177. Incubation of cultured myocytes for 24 hours with the ACE inhibitor captopril (1 micromol/L) increased beta-AR density by 35% and enhanced the response of cells to isoproterenol but not to forskolin. Neither an angiotensin-II type 1 (AT1) receptor antagonist, CV-11974, nor angiotensin-I affected beta-AR density. However, the bradykinin B2 receptor antagonist Hoe 140 abolished the effect of captopril on beta-AR upregulation in a dose-dependent manner. The protein kinase C inhibitor staurosporine (20 nmol/L) but neither indomethacin nor L-NAME also inhibited captopril-induced upregulation of beta-ARs. Exogenous bradykinin increased the spontaneous beating frequency of cultured myocytes and Hoe 140 abolished this effect. Bradykinin level in the medium increased 1.4-fold by the treatment of cultured myocytes with captopril for 24 hours.

CONCLUSIONS

The results suggest that captopril enhances beta-AR responsiveness by inducing beta-AR upregulation and that the latter effect is mediated by activation of bradykinin B2 receptors and protein kinase C. These observations also offer insight into the different roles of ACE inhibitors and AT1 receptor antagonists in the treatment of heart failure.

Postrest shortening of the action potential duration in rabbits: in vitro and in vivo correlation

Previous evidence has shown that the action potential duration of rabbit ventricular muscle cells shortens after a rest period (postrest shortening). However, there has not been much research on postrest shortening in the intact heart. We recorded transmembrane action potentials (TAPs) of isolated papillary muscle from rabbit ventricle with glass microelectrodes and monophasic action potentials (MAPs) of the rabbit left ventricular endocardium with contact electrodes. In the in vitro experiments, repetitive regular stimuli (S1) at a cycle length of 1 sec were followed by a single extrastimulus (S2) at coupling intervals (S1S2) ranging between 0.5 sec and 8 sec. The increase in the S1S2 interval resulted in a progressive shortening of the duration of TAP elicited by the S2, which was abolished by the simultaneous application of 1 mmol/L 4-aminopyridine and 2 micromol/L ryanodine. In the in vivo experiments, regular right ventricular pacing (S1) at a cycle length of 0.35 sec was followed by a single extrastimulus (S2) with coupling intervals (S1S2) ranging between 0.25 sec and 3 sec. The increase in the S1S2 interval also resulted in a progressive shortening of the duration of MAP elicited by the S2. This is the first report to demonstrate postrest shortening in the intact heart, which probably occurs because of a mechanism analogous to that observed in the isolated ventricular muscle.

Elucidating the mechanism of cesium-induced sustained monomorphic ventricular tachycardia in rabbits

The mechanisms of sustained ventricular tachycardia (VT) induced by large cumulative dose of cesium chloride (Cs) remains unclear. Seven anesthetized rabbits were intravenously injected with Cs (1 mmol/kg) 3 times at 20-min intervals. The surface ECG and monophasic action potential of the left ventricular endocardium were simultaneously recorded. In another 12 rabbits, transmembrane action potentials of right ventricular muscles were recorded with glass microelectrodes. In experiments in vivo, sustained monomorphic VT was induced after the third injection of Cs, whereas the early afterdepolarization (EAD)-related nonsustained polymorphic VT was induced after the second injection. Overdrive pacing during the sustained VT resulted in postdrive acceleration. The pacing and recovery cycle lengths showed an inverse relation. In experiments in vitro, preparations were superfused with Tyrode's solution containing 7.5 mM Cs. Cs initially induced EADs. Additional exposure to Cs depolarized the membrane potential, which consequently attained threshold, producing spontaneous activities. Further exposure resulted in an induction of sustained rhythms that were accelerated by overdrive pacing. Our results indicate that the sustained rhythms at low membrane potential induced by a long exposure to Cs in vitro may underlie an electrophysiologic mechanism for the sustained VT induced after large cumulative dose of Cs in vivo.

Noninvasive hemodynamic measurements of superior mesenteric artery in the prediction of portal pressure response to propranolol

BACKGROUND/AIMS

The portal pressure response to propranolol administration is heterogeneous in patients with cirrhosis. The aim of this study was to examine the diagnostic accuracy of noninvasive hemodynamic parameters of superior mesenteric artery (SMA) and femoral artery (FA) in the prediction of portal pressure response to propranolol.

METHODS

Twenty-six patients with cirrhosis were studied. Portal pressure was assessed by measurements of hepatic venous pressure gradient. Mean arterial pressure and heart rate were also recorded. Cardiac index, and flow velocity of SMA and FA, and pulsatility index of SMA and FA were then measured by means of Doppler ultrasonography. After intravenous propranolol administration (0.10 mg/kg), the above measurements were repeated.

RESULTS

Propranolol significantly reduced cardiac index, heart rate, SMA flow velocity, and FA flow velocity and increased SMA pulsatility index and FA pulsatility index. Although propranolol significantly decreased hepatic venous pressure gradient, a reduction of > or =20% was seen in only 10 patients (good responders); the remaining 16 patients exhibited <20% reduction (poor responders). No significant differences in clinical and baseline hemodynamic data were found in the two groups. There were no also significant differences in changes in heart rate and cardiac index. However, reductions in SMA and FA flow velocity were significantly greater in good responders than in poor responders. Although there was no the increase in FA pulsatility index, the increase in SMA pulsatility index was significantly greater in good responders than in poor responders. When appropriate cut-off points were determined for these variables, overall predictive values of SMA flow velocity (-20%) and SMA pulsatility index (+15%) were 91% and 83%, whereas the overall predictive value of FA flow velocity (-25%) was only 69%.

CONCLUSIONS

These results suggest that SMA flow velocity and SMA pulsatility index, but not FA flow velocity and FA pulsatility index, are useful noninvasive parameters in the prediction of portal pressure response to propranolol administration.

Circadian rhythm of the signal averaged electrocardiogram and its relation to heart rate variability in healthy subjects

OBJECTIVE

To examine the circadian variation in the signal averaged electrocardiogram (saECG) and heart rate variability and investigate their relations in healthy subjects.

METHODS

24 hour ECGs were obtained with a three channel recorder using bipolar X, Y, and Z leads in 20 healthy subjects. The following variables were determined hourly: heart rate, filtered QRS (f-QRS) duration, low and high frequency components of heart rate variability (LF and HF), and the LF/HF ratio.

RESULTS

Heart rate, f-QRS duration, HF, and the LF/HF ratio showed significant circadian rhythms, as determined by the single cosinor method. Heart rate and the LF/HF ratio increased during daytime, and f-QRS duration and HF increased at night. f-QRS duration was negatively correlated with heart rate (r = 0.95, p < 0.001) and the LF/HF ratio (r = 0.94, p < 0.001) and positively with HF (r = 0.93, p < 0.001).

CONCLUSIONS

f-QRS duration has a significant circadian rhythm in healthy subjects and is closely related to the circadian rhythm of autonomic tone.

[Telomerase activity in pancreatic juice for the preoperative diagnosis of pancreatic cancer]

Although many diagnostic challenges have been tried in pancreatic cancer, its prognosis still remains poor. One of the reason that it is difficult to diagnose using present diagnostic procedure in early stage of pancreatic cancer. Therefore, we tried new procedure using telomerase activity from pancreatic juice. In this study, telomerase was assayed by use of pancreatic duct cells obtained preoperatively from 32 cases with pancreatic duct abnormalities. Telomerase activity was undetectable in all 17 subjects with benign pancreatic diseases, whereas 13 (87%) of 15 subjects with pancreatic cancer had detectable telomerase activity. Interestingly, we also detected telomerase activity in the case of carcinoma in situ. If future studies confirm, the detection of telomerase activity of pancreatic duct cells may become an useful tool for diagnosis of pancreatic cancer, perhaps at early stages.

The establishment of a preoperative diagnosis of pancreatic carcinoma using cell specimens from pancreatic duct brushing with special attention to p53 mutations

BACKGROUND

Previously, the authors reported that 82% of cases of pancreatic carcinoma were positive for p53 in cytologic specimens obtained by selective endoscopic pancreatic duct brushing (SEPB). However, there was an extreme discrepancy between the authors' data of p53 overexpression using cytologic specimens and other reports using surgically resected specimens. In this study, the authors demonstrate that p53 positive cells precisely reflect its gene mutations, and also establish systematic procedures for the preoperative diagnosis of patients with pancreatic carcinoma.

METHODS

The authors examined 44 cases of pancreatic carcinoma, 30 cases of chronic pancreatitis, and 9 cases of papillary adenoma. In all cases, pathologic diagnosis was made by surgery or autopsy. The conventional cytology and p53 immunocytology were performed simultaneously in the cell specimens obtained by SEPB. In the cases immunostained for p53, DNA was extracted selectively from p53 immunostained cells using a light microscope. p53 mutations in exons 5 to 8 were examined by direct sequencing.

RESULTS

Forty of 44 pancreatic carcinomas (91%) were diagnosed correctly by the methods of conventional cytology associated with p53 immunocytology. p53 mutations were detected in 12 of 14 cases that were positive for p53 (86%). Four of six cases that were inoperable due to massive metastasis or invasion had the mutation at codon 273 (CGT to CAT) in exon 8.

CONCLUSIONS

These results suggest that p53 immunocytology reflects its gene mutations precisely, and that the point mutation at codon 273 (CGT to CAT) of p53 may play an important role in the invasive potential and metastasis of pancreatic carcinoma.

Role of extravariceal collateral channels in the development of portal-hypertensive gastropathy before and after sclerotherapy

We investigated whether extravariceal collateral pattern contributed to the development of portal-hypertensive gastropathy (PHG) before and after sclerotherapy. Ninety-nine patients with cirrhosis and large esophageal varices were examined in this retrospective study. They were divided into four groups according to transhepatic portographic findings: group A (with neither paraesophageal veins nor gastrorenal shunt; n = 46), group B (with paraesophageal veins; n = 27), group C (with gastrorenal shunt; n = 14), and group D (with paraesophageal veins and gastrorenal shunt; n = 12). To assess PHG, endoscopic examinations were carried out before and 1 week and 1 month after sclerotherapy. The severity of PHG was classified according to a modified McCormack's classification and scored as: absence, 0; mild, 1; severe, 2. There were no significant differences in age, sex, cause of cirrhosis, severity of liver dysfunction, and extent of esophageal varices in the four groups. The PHG score before sclerotherapy was significantly higher in group A than in either group C (P < 0.05) or group D patients (P < 0.05). The calculated, integrated incremental change in PHG score after sclerotherapy was significantly higher in group A than in group C (P < 0.01) and group D patients (P < 0.01). Although the integrated change in PHG score was lower in group B than in group A patients, the difference was not significant (P = 0.68). These results suggest that gastrorenal shunt, but not paraesophageal veins, may play a protective role in the development of PHG before and after sclerotherapy.

Signal-averaged electrocardiogram shows a heart rate dependent diurnal variation in healthy subjects

It has not been determined if signal-averaged electrocardiograms (SAECGs) have a diurnal variation. We recorded 3-channel 24-hour ECGs in 30 healthy volunteers and calculated the following parameters for the first 500 sec of every hour over the 24-hour period: the mean heart rate, the filtered QRS duration (f-QRS), the root-mean-square voltage of the signals in the last 40 msec of the QRS (RMS40), and the duration of low-amplitude signals (< 40 microV) in the terminal portion of the QRS (LAS40). Heart rate and RMS40 increased in the daytime compared with the nighttime; f-QRS and LAS40 increased during the nighttime hours. The f-QRS and LAS40 were negatively correlated with heart rate in all and 22 (73%) of 30 subjects, respectively, and RMS40 was positively correlated with heart rate in 21 subjects (70%). In conclusion, SAECGs exhibit a clear diurnal variation in healthy subjects, which is closely related to changes in heart rate.

Dynamics of QT interval in a patient with long QT syndrome and a normal QT interval

A case report of a 15-year-old girl who experienced syncope and torsades de pointes is presented. The girl had a normal QT interval (QTc=0.37 sec) on the resting electrocardiogram (ECG). Infusion of isoproterenol induced QT prolongation (QTc=0.62 sec) and frequent occurrence of multiform ventricular premature beats. Her Holter ECG showed a prolongation of the QTc interval with a shortening of the RR interval. Low-frequency power (LF) and high-frequency power (HF) of heart rate variability were evaluated from the Holter ECG. The patient showed a statistically significant negative QTc/HF and a significant positive QTc/(LF/HF) relationship, whereas none of the age- and sex-matched healthy subjects showed these relationships. The slope of the QT/RR relationship for the patient was below the lower limit of the normal range. This report describes the unusual relationship of QT interval to RR interval and heart rate variability in a long QT syndrome patient with a normal QT interval on resting ECG.

Upright posture decreases esophageal varices flow velocity in patients with cirrhosis

BACKGROUND/AIMS

Patients with cirrhosis tend to have esophageal variceal bleeding episodes at night, rather than during the day time. Since human beings carry on ordinary activities in the upright posture in the day time and are recumbent at night, we hypothesized that posture may be a factor related to a circadian variation of variceal bleeding. The aim of this study was to examine the effect of upright posture on esophageal varices hemodynamics in patients with cirrhosis.

METHODS

Nine patients with cirrhosis and esophageal varices were included in a crossover study performed on 2 separate days. On the non-endoscopic day, cardiac output, portal vein flow velocity, and superior mesenteric artery flow velocity were measured with percutaneous Doppler ultrasonography. Plasma renin activity and plasma norepinephrine concentrations were also determined. On the endoscopic day, in addition to the above measurements, esophageal varices flow velocity was measured using transesophageal Doppler ultrasonography. These measurements were performed in the supine position and 20 min after the assumption of the upright position.

RESULTS

On the non-endoscopic day, the upright posture significantly decreased cardiac output, portal vein flow velocity, and superior mesenteric artery flow velocity. Plasma renin activity and plasma norepinephrine concentration were significantly increased after assumption of the upright position. On the endoscopic day, similar hemodynamic and hormonal changes were observed. In addition, the upright posture significantly decreased esophageal varices flow velocity. Furthermore, the magnitude of the reduction in esophageal varices flow velocity (-42%) was significantly greater than that in portal vein flow velocity (-22%, p<0.01) and that in superior mesenteric artery flow velocity (-25%, p<0.01). Although the change in esophageal varices flow velocity was not significantly correlated with that in plasma renin activity (r=-0.28) and that in plasma norepinephrine concentration (r=-0.10), it was significantly correlated with the change in superior mesenteric artery flow velocity (r=0.73, p<0.05).

CONCLUSIONS

The upright posture decreases esophageal varices flow velocity mainly because of the reduction in splanchnic blood flow. This effect may contribute to a low prevalence of esophageal variceal bleeding in the day time in patients with cirrhosis.

Ligation plus low-volume sclerotherapy for high-risk esophageal varices: comparisons with ligation therapy or sclerotherapy alone

Endoscopic variceal ligation therapy (EVL) seems to be a more effective and safer method than endoscopic injection variceal sclerotherapy (EVS) for treating bleeding esophageal varices. However, EVL may entail a higher recurrence rate than EVS. The aim of this study was to examine whether EVL combined with low-dose EVS reduced the recurrence rate compared to treatment with EVL alone and reduced the complication rate compared to treatment with EVS alone. In this prospective study, 59 patients with cirrhosis and high-risk (F2 or F3, red color sign ++ or ) esophageal varices were enrolled. They were randomly assigned to an EVS group (n = 18), an EVL group (n = 20), and a combination EVL plus low-dose EVS group (n = 21). After the eradication of varices, follow-up endoscopic examinations were carried out for 24 months to determine the recurrence of varices. Complications, e.g., severe dysphagia, fever, renal dysfunction and pleuritis were also evaluated. The recurrence-free rate was significantly lower in the EVL group (60% at 24 months) than in either the EVS group (90%, P < 0.05) or the combination group (88%, P < 0.05). However, no significant difference was found between the EVS group and the combination group. The complication rate was significantly higher in the EVS group (50%) than in either the EVL group (5%, P < 0.01) or the combination group (10%, P < 0.01). The combination therapy seems to be useful to improve the benefits achieved with EVL alone and to reduce the harmful effects induced by EVS alone. EVL plus low-volume EVS is advisable in the treatment of high-risk esophageal varices.

Effect of large fundal varices on changes in gastric mucosal hemodynamics after endoscopic variceal ligation

BACKGROUNDS AND STUDY AIMS: Effect of endoscopic variceal ligation (EVL) on gastric mucosal hemodynamics would differ in patients with and without large fundal varices. The aim of this study was to test this hypothesis.

PATIENTS AND METHODS

Twenty-seven patients with cirrhosis and large sized esophageal varices were prospectively studied. There were eight patients with large fundal varices and 19 patients without large fundal varices. Before EVL, gastric mucosal hemodynamics were endoscopically assessed by laser-Doppler velocimetry and reflectance spectrophotometry in the antrum and the corpus. In the reflectance spectrophotometric measurements, gastric mucosal hemoglobin content (IHb) and gastric mucosal oxygen saturation (ISO2) were determined. The severity of portal-hypertensive gastropathy (PHG) was also recorded at the antrum and the corpus. For data analysis, PHG was scored (absent, 0; mild, 1; severe, 2; bleeding, 3). These measurements were repeated after initial (three days after initial session) and repeated (seven days after last session) EVL.

RESULTS

At the antrum, neither PHG score nor gastric mucosal hemodynamic parameters were modified after initial and repeated EVL in patients with and without large fundal varices. In addition, no significant differences of the integrated changes in PHG score and gastric mucosal hemodynamic parameters were observed in the two groups. At the corpus, PHG score significantly increased after initial and repeated EVL in patients without large fundal varices. In these patients, laser-Doppler signal and ISO2 significantly decreased and IHb significantly increased after initial and repeated EVL. In contrast, PHG score, laser-Doppler signal, and ISO2 did not change significantly in patients with large fundal varices, although IHb transiently increased after initial EVL. Furthermore, the integrated changes in PHG score and gastric mucosal hemodynamic parameters were significantly lower in patients with large fundal varices than in those without.

CONCLUSION

The aggravation of PHG after EVL is due to congestion of the gastric mucosal circulation. The presence of large fundal varices plays a protective role in the development of EVL-induced gastric mucosal hemodynamic derangement.

Prognostic factors in cirrhotic patients receiving long-term sclerotherapy for the first bleeding from oesophageal varices

OBJECTIVE AND DESIGN

The aim of this study was to identify prognostic factors in cirrhotic patients receiving long-term sclerotherapy for their first bleeding from oesophageal varices.

METHODS

Ninety-eight patients with acute bleeding from oesophageal varices receiving long-term endoscopic injection sclerotherapy were retrospectively investigated. Thirteen variables (five qualitative and eight quantitative) related to clinical, biological, and radiographic features were collected at admission. The qualitative variables were: gender, hepatocellular carcinoma, cause of cirrhosis, ascites and degree of encephalopathy. The quantitative variables were age, bilirubin, albumin, prothrombin index, number of sessions of sclerotherapy, volume of ethanolamine oleate, time taken to reach the hospital and shock index. These variables were examined with a multivariate analysis using stepwise logistic regression procedures and a prognostic index was calculated from the Cox equation. The predictive power of the final Cox model was prospectively tested in 43 patients with cirrhosis receiving long-term sclerotherapy for their first variceal bleeding.

RESULTS

Of the 13 variables studied in a multivariate analysis using a logistic regression model, four had an independent prognostic value: the presence of hepatocellular carcinoma, bilirubin, albumin and time taken to reach the hospital. When the Cox model was examined in an independent set of 43 patients, there were no statistically significant differences between the observed and expected survival.

CONCLUSION

Prognosis of patients with bleeding from oesophageal varices is related to residual liver function and time taken to reach the hospital. Furthermore, the presence of hepatocellular carcinoma is an additional risk factor.

[The role of similarity and category in confirmation judgement of category-based induction: an examination of the similarity-coverage model]

Induction is called category-based induction if its premises and conclusion are of the form "All members of a category C have property P." Osherson, Smith, Wilkie, Lopez, and Shafir (1990) advanced similarity-coverage model. But their data from a quantitative test of specific induction did not necessarily support the model. Three experiments investigate whether their modeling of similarity and coverage was not valid or their experiments were not valid. The following results were obtained. Coverage did not affect confirmation judgement in premise-variation type induction which Osherson et al. (1990) dealt with, and coverage effect was verified in conclusion-variation type induction which is more everyday and needs less processing load. In the latter case, coverage had to be weighted by typicality of conclusion in an inclusive category. And when mixed inductions were included, confirmation judgement was based not on coverage but on a belonging relation to an upper category and similarity between premise categories and a conclusion category.

Influence of extravariceal collateral channel pattern on recurrence of esophageal varices after sclerotherapy

We investigated the influence of extravariceal collateral channel pattern on the recurrence of esophageal varices after sclerotherapy. One hundred and fifteen patients with cirrhosis and esophageal varices were studied. They were divided into four groups according to extravariceal collateral pattern on portal venography. Group 1 patients had neither paraesophageal veins nor gastrorenal veins (n = 49); group 2 patients had paraesophageal veins only (n = 30); group 3 patients had gastrorenal veins only (n = 25); and group 4 patients had paraesophageal veins plus gastrorenal veins (n = 11). Sclerotherapy was repeated to eradicate esophageal varices and follow-up endoscopic examination were performed. The overall recurrence-free rate at 36 months was 68%. The log-rank test showed the recurrence-free rate to be significantly higher in group 3 (76%) and group 4 patients (89%) than in group 1 patients (51%; P < 0.05 and P < 0.05, respectively). Although the recurrence-free rate was higher in group 4 than in group 2 patients (59%), this did not reach the level of significance (P = 0.10). No significant differences were found between other pairs of groups. These results suggest that gastrorenal veins play an important role in the protection against recurrent esophageal varices after sclerotherapy, while the protective role of paraesophageal veins appears to be small.

Effects of glucagon on superior mesenteric artery and femoral artery haemodynamics in humans

OBJECTIVE

It remains unclear whether glucagon is a localized splanchnic arterial vasodilator in humans. This study examined this issue by assessing the haemodynamic effect of exogenous glucagon on splanchnic and extrasplanchnic arteries.

METHODS

After an overnight fast, flow velocity of superior mesenteric artery and femoral artery was recorded by means of echo-Doppler in 10 controls and 10 patients with cirrhosis. Mean arterial pressure, heart rate and plasma glucagon level were also determined. These measurements were repeated after intramuscular injection of glucagon (1 mg) at 15 min and 30 min.

RESULTS

Patients with cirrhosis had much higher glucagon levels than controls (P < 0.01). Plasma glucagon level rose following glucagon administration in controls (P < 0.01) and patients with cirrhosis (P < 0.01). Glucagon administration had no effect on mean arterial pressure, heart rate and femoral artery velocity in controls and patients with cirrhosis. In contrast, superior mesenteric artery velocity significantly increased after glucagon administration in both groups (P < 0.01, P < 0.01), although the effect was less pronounced in patients with cirrhosis than in controls (P < 0.05).

CONCLUSION

These data suggest that glucagon might be a localized splanchnic arterial vasodilator. Thus, glucagon may be one of the factors contributing to the pathogenesis of the splanchnic hyperdynamic circulation seen in patients with cirrhosis.

Splanchnic and extrasplanchnic arterial hemodynamics in patients with cirrhosis

BACKGROUND/AIMS

This study was designed to assess the contribution of splanchnic and extrasplanchnic vascular hemodynamics to the hyperdynamic circulation in patients with cirrhosis.

METHODS

Cardiac index and flow volume index and pulsatility index (PI) of superior mesenteric artery (SMA) and femoral artery (FA) were measured with Doppler ultrasonography in 40 controls and 86 patients with cirrhosis (Child-Pugh grade A=41, grade B=30, and grade C=15). Mean arterial pressure was also recorded to calculate systemic vascular resistance index.

RESULTS

Systemic vascular resistance index was significantly lower in each Child-Pugh group than in controls. SMA blood flow index was significantly higher in each Child-Pugh group than in controls and the increase in SMA blood flow index paralleled the degree of liver dysfunction. SMA-PI was significantly lower in each Child-Pugh group than in controls and the decrease in SMA-PI paralleled the degree of liver dysfunction. FA blood flow index was slightly higher in Child-Pugh grade A patients and significantly higher in grade B patients than in controls, whereas grade C patients had normal FA blood flow index. FA-PI was significantly lower in grade A and grade B patients than in controls, whereas grade C patients had normal FA-PI. When all patients were examined together, SMA-PI significantly correlated with systemic vascular resistance index (r=0.69, p<0.01). In contrast, FA-PI did not significantly correlate with systemic vascular resistance index (r=0.15, p=0.18).

CONCLUSIONS

Splanchnic arterial vasodilatation plays an important role in the pathogenesis of decreased systemic vascular resistance seen in patients with cirrhosis.

Splanchnic hemodynamic pattern and liver function in patients with cirrhosis and esophageal or gastric varices

OBJECTIVES

This study was designed to characterize the splanchnic hemodynamic pattern and liver function in patients with cirrhosis and esophageal or gastric varices.

METHODS

Forty control subjects and 112 patients with cirrhosis were studied. Portal inflow (the sum of superior mesenteric arterial and splenic arterial flows), portal venous flow, and collateral flow (the difference between portal inflow and portal venous flow) were measured using duplex ultrasonography. Endoscopic examination showed that 45 patients had no varices or small esophageal or gastric varices, 49 had large esophageal varices, and 18 had large gastric varices. Liver function was assessed by Pugh-Child score.

RESULTS

Portal inflow was significantly greater in patients with large esophageal varices or large gastric varices than in control subjects and patients with no varices or small esophageal or gastric varices. Portal venous flow was significantly lower in patients with large gastric varices than in the other three groups. Collateral flow was significantly greater in patients with large gastric varices than in patients with large esophageal varices. The Pugh-Child score was significantly higher in patients with large gastric varices than in patients with large esophageal varices. The Pugh-Child score was also inversely correlated with portal venous flow (r = -0.35, p < 0.01) and directly correlated with collateral flow (r = 0.59, p < 0.01).

CONCLUSIONS

Both patients with esophageal varices and those with gastric varices have increased portal inflow. However, patients with gastric varices, in contrast to patients with esophageal varices, have a reduced portal venous flow associated with an increased collateral flow. Such a portal outflow pattern may contribute to the worse liver function seen in patients with gastric varices.

Effect of posture-induced blood volume expansion on systemic and regional hemodynamics in patients with cirrhosis

BACKGROUND/AIMS

This study aimed to investigate the effects of posture-induced blood volume expansion on systemic and regional hemodynamics in patients with cirrhosis.

METHODS

The mean arterial pressure, cardiac index, peripheral vascular resistance index, and flow volume index of the superior mesenteric artery (SMA) and femoral artery (FA) were measured in 10 patients with cirrhosis and portal hypertension and 10 controls after they had been standing for 2 h. Plasma atrial natriuretic peptide, plasma renin activity, and plasma glucagon levels were also determined. These measurements were repeated after 30 min and 60 min when the patients were recumbent.

RESULTS

In the upright posture, systemic hemodynamics, FA blood flow index, plasma atrial natriuretic peptide level, and plasma renin activity level were similar in patients and controls. However, SMA blood flow index and plasma glucagon level were significantly higher in patients than in controls. On the assumption of the supine position, cardiac index and plasma atrial natriuretic peptide level significantly increased in the two groups, but the changes were greater in patients than in controls. Mean arterial pressure remained unchanged. The reduction in peripheral vascular resistance index was therefore greater in patients in controls. SMA and FA blood flow index increased significantly in the two groups, but the changes were greater in patients than in controls. Furthermore, SMA blood flow fraction (SMA blood flow index/cardiac index) was steady in controls, whereas it increased significantly in patients. In contrast, FA blood flow fraction (FA blood flow index/cardiac index) remained unchanged in the two groups. In patients, the change in peripheral vascular resistance index was correlated inversely with that of SMA blood flow index, but not with that of FA blood flow index. Plasma renin activity level dropped significantly, but the decline was similar in the two groups. Plasma glucagon level was not modified in either group.

CONCLUSIONS

In patients with cirrhosis, splanchnic vasodilation appears to be present, even in the upright position, and further abnormal vasodilation occurs on recumbency-induced blood volume expansion. This abnormal shear-stress phenomenon observed in the splanchnic circulation seems to be mediated by a local vasodilator rather than a general vasodilator.