Cross-field transport by instabilities and blobs in a magnetized toroidal plasma

The mechanisms for anomalous transport across the magnetic field are investigated in a toroidal magnetized plasma. The role of plasma instabilities and macroscopic density structures (blobs) is discussed. Examples from a scenario with open magnetic field lines are shown. A transition from a main plasma region into a loss region is reproduced. In the main plasma, which includes particle and heat source locations, the transport is dominated by the fluctuation-induced particle and heat flux associated with a plasma instability. On the low-field side, the cross-field transport is ascribed to the intermittent ejection of macroscopic blobs propagating toward the outer wall. It is shown that instabilities and blobs represent fundamentally different mechanisms for cross-field transport.

Stress and crystallization of plasma enhanced chemical vapour deposition nanocrystalline silicon films

Nanocrystalline Si films were prepared with a RF-PECVD system using different SiH4/H2 ratios, plasma powers, substrate temperatures and annealing conditions. The film's intrinsic stress was characterized in relation to the crystallization fraction. Results show that an increasing H2 gas ratio, plasma power or substrate temperature can shift the growth mechanism across a transition point, past which nanocrystalline Si is dominant in the film structure. The film's intrinsic stress normally peaks during this transition region. Different mechanisms of stress formation and relaxation during film growth were discussed, including ion bombardment effects, hydrogen induced bond-reconstruction and nanocomposite effects (nanocrystals embedded in an amorphous Si matrix). A three-parameter schematic plot has been proposed which is based on the results obtained. The film structure and stress are presented in relation to SiH4 gas ratio, plasma power and temperature.

Experimental observation of the blob-generation mechanism from interchange waves in a plasma

The mechanism for blob generation in a toroidal magnetized plasma is investigated using time-resolved measurements of two-dimensional structures of electron density, temperature, and plasma potential. The blobs are observed to form from a radially elongated structure that is sheared off by the E x B flow. The structure is generated by an interchange wave that increases in amplitude and extends radially in response to a decrease of the radial pressure scale length. The dependence of the blob amplitude upon the pressure radial scale length is discussed.

Universal statistical properties of drift-interchange turbulence in TORPEX plasmas

A unique parabolic relation is observed to link skewness and kurtosis of around ten thousand density fluctuation signals, measured over the whole cross section of a toroidal magnetized plasma for a broad range of experimental conditions. All the probability density functions of the measured signals, including those characterized by a negative skewness, are universally described by a special case of the Beta distribution. Fluctuations in the drift-interchange frequency range are necessary and sufficient to assure that probability density functions can be described by this specific Beta distribution.

Detection of tissue abnormalities in normal mucosa surrounding colorectal cancer using an endocytoscopy system

The endocytoscopy system is a novel diagnostic technique that provides extremely high-magnification imaging of the gastrointestinal mucosa. We are currently using a prototype Olympus endocytoscope for clinical research in gastrointestinal tumors. In one surgical specimen obtained after resection of a cancer of the transverse colon, focal abnormalities of colonic glands were detected 7 cm away from the primary tumor, within macroscopically normal mucosa. Our finding, which was confirmed by histopathological examination, suggests the need for further clinical investigation to assess whether endocytoscopy is able to identify premalignant changes in apparently normal mucosa. This could potentially be useful for accurate evaluation before planning minimally invasive therapy.

Deterministic shape-selective synthesis of nanowires, nanoribbons and nanosaws by steady-state vapour-transport

We demonstrate the deterministic shape-selective synthesis and growth of CdSe nanowires, nanosaws and nanoribbons by a simple vapour-transport process in a tube furnace. The key step, in order to achieve reproducible shape selectivity for a given set of deposition parameters, is to exclude any effects of the temperature ramping. We prove that an efficient precursor-flow shutter is achieved just by varying the total furnace pressure. We then present a shape-diagram linking the different nanocrystals morphologies to only two parameters: powder and substrate temperature. These are varied in the 550-700 °C and 400-600 °C range, respectively. A model explaining the shape control is discussed.

Effects of a vertical magnetic field on particle confinement in a magnetized plasma torus

The particle confinement in a magnetized plasma torus with superimposed vertical magnetic field is modeled and measured experimentally. The formation of an equilibrium characterized by a parallel plasma current canceling out the grad B and curvature drifts is described using a two-fluid model. Characteristic response frequencies and relaxation rates are calculated. The predictions for the particle confinement time as a function of the vertical magnetic field are verified in a systematic experimental study on the TORPEX device, including the existence of an optimal vertical field and the anticorrelation between confinement time and density.

Platelet count/spleen diameter ratio: proposal and validation of a non-invasive parameter to predict the presence of oesophageal varices in patients with liver cirrhosis

BACKGROUND AND AIMS

Cirrhotic patients frequently undergo screening endoscopy for the presence of oesophageal varices (OV). In the future, this social and medical burden will increase due to the greater number of patients with chronic liver disease and their improved survival. In this study, our aims were (1) to identify clinical, biochemical, and ultrasonographic parameters which might non-invasively predict the presence of OV in patients with liver cirrhosis; (2) to evaluate the reproducibility of the obtained results in a different, although related, further group of patients; and (3) to assess the predictiveness of the identified rules in patients with compensated cirrhosis.

METHODS

In the first part of the study we retrospectively evaluated the presence of OV in 145 cirrhotic patients, and in the second part we evaluated the reproducibility of the study results in a subsequent group of 121 patients. Finally, we evaluated these parameters in a subgroup of 145 patients with compensated disease. All 266 patients underwent a complete biochemical workup, upper digestive endoscopy, and ultrasonographic measurement of spleen bipolar diameter. Platelet count/spleen diameter ratio was calculated for all patients.

RESULTS

The prevalence rates of OV were 61% and 58% in the first and second groups of patients, respectively. In the first part of the study, we found that platelet count, spleen diameter, platelet count/spleen diameter ratio, and Child- Pugh class were significantly different among patients with or without OV, although the platelet count/spleen diameter ratio was the only parameter which was independently associated with the presence of OV in a multivariate analysis. A platelet count/spleen diameter ratio cut off value of 909 had 100% negative predictive value for a diagnosis of OV. This result was reproduced in the second group of patients as well as in patients with compensated disease. In a cost-benefit analysis, screening cirrhotic patients according to the "platelet count/spleen diameter ratio strategy" was far more cost effective compared with the "scope all strategy".

CONCLUSIONS

The platelet count/spleen diameter ratio is the only parameter which is independently associated with the presence of OV, and its negative predictive value is reproducible. Its use is of value even in the subgroup of patients with compensated disease, and it is also cost effective.

Dynamical plasma response during driven magnetic reconnection

Direct measurements of a collisionless current channel during driven magnetic reconnection are obtained for the first time on the Versatile Toroidal Facility. The size of the diffusion region is found to scale with the electron drift orbit width, independent of the ion mass and plasma density. Based on experimental observations, analytic expressions governing the dynamical evolution of the current profile and the formation of the electrostatic potential that develops in response to the externally imposed reconnection drive are established. This time response is closely linked to the presence of ion polarization currents.

MELD scoring system is useful for predicting prognosis in patients with liver cirrhosis and is correlated with residual liver function: a European study

BACKGROUND

Indices for predicting survival are essential for assessing prognosis and assigning priority for liver transplantation in patients with liver cirrhosis. The model for end stage liver disease (MELD) has been proposed as a tool to predict mortality risk in cirrhotic patients. However, this model has not been validated beyond its original setting.

AIM

To evaluate the short and medium term survival prognosis of a European series of cirrhotic patients by means of MELD compared with the Child-Pugh score. We also assessed correlations between the MELD scoring system and the degree of impairment of liver function, as evaluated by the monoethylglycinexylidide (MEGX) test.

PATIENTS AND METHODS

We retrospectively evaluated survival of a cohort of 129 cirrhotic patients with a follow up period of at least one year. The Child-Pugh score was calculated and the MELD score was computed according to the original formula for each patient. All patients had undergone a MEGX test. Multivariate analysis was performed on all variables to identify the parameters independently associated with one year and six month survival. MELD values were correlated with both Child-Pugh scores and MEGX test results.

RESULTS

Thirty one patients died within the first year of follow up. Child-Pugh and MELD scores, and MEGX serum levels were significantly different among patients who survived and those who died. Serum creatinine, international normalised ratio, and MEGX(60) were independently associated with six month mortality while the same variables and the presence of ascites were associated with one year mortality. MELD scores showed significant correlations with both MEGX values and Child-Pugh scores.

CONCLUSIONS

In a European series of cirrhotic patients the MELD score is an excellent predictor of both short and medium term survival, and performs at least as well as the Child-Pugh score. An increase in MELD score is associated with a decrease in residual liver function.

13C-aminopyrine breath test to evaluate severity of disease in patients with chronic hepatitis C virus infection

BACKGROUND

There are few data on the use of the 13C-aminopyrine breath test to evaluate the severity of disease in patients with hepatitis C virus-related chronic liver disease, although these patients represent one of the most important problems in clinical hepatology.

AIMS

To compare 13C-aminopyrine breath test results of patients with hepatitis C virus-related chronic hepatitis and Child-Pugh class A cirrhosis with those of normal subjects, and to evaluate different methods of expressing 13C-aminopyrine breath test results.

METHODS

Twenty-four patients with hepatitis C virus-related chronic hepatitis and 17 patients with Child-Pugh class A cirrhosis underwent 13C-aminopyrine breath test. Breath samples were collected every 30 min up to 2 h after 13C-aminopyrine administration. 13C-Aminopyrine breath test results were expressed as a percentage of the administered dose of 13C recovered per hour (% dose/h) and the cumulative percentage of administered dose of 13C recovered over time (% dose cum). Nineteen healthy subjects served as controls. Patients with hepatitis C virus-related chronic hepatitis were divided into subgroups on the basis of histological staging and grading.

RESULTS

The 13C-aminopyrine breath test result (% dose/h) at 30 min was significantly different among the three subgroups of subjects (normal subjects, 11.5 +/- 3.5; chronic hepatitis patients, 8.1 +/- 4.1; cirrhosis patients, 5.0 +/- 3.1; P < 0.0005). Moreover, the differences between chronic hepatitis and cirrhosis patients were statistically significant (P < 0.03). The fibrosis score showed a significant inverse correlation with the 13C-aminopyrine breath test result (% dose/h) at 30 min (rs=- 0.409, P=0.05). The 13C-aminopyrine breath test result (% dose/h) at 30 min also allowed normal subjects and chronic hepatitis patients with low (< or = 2) or high (> 2) fibrosis scores to be distinguished. The 13C-aminopyrine breath test results (% dose cum) at 30, 60 and 90 min allowed discrimination between normal subjects and chronic hepatitis and cirrhosis patients. The 13C-aminopyrine breath test result (% dose cum) was also able to distinguish between normal subjects and chronic hepatitis patients with high but not low fibrosis scores. Both 13C-aminopyrine breath test results (% dose/h and % dose cum) at 120 min allowed the differentiation between normal subjects and chronic hepatitis patients with high (> or = 6) necro-inflammatory activity.

CONCLUSIONS

In patients with hepatitis C virus-related chronic liver disease, the 13C-aminopyrine breath test proved to be safe and easy to perform, and was able to evaluate different degrees of liver function impairment which were partly correlated to clinical and histological evaluation. In future studies, 13C-aminopyrine breath test results should be expressed in a standardized fashion to permit comparison.

Impairment of cytochrome P-450-dependent liver activity in cirrhotic patients with Helicobacter pylori infection

BACKGROUND

Helicobacter pylori gastric infection has been associated with various digestive and extra-digestive diseases. The systemic influence of gastric H. pylori infection seems to be mediated by the release of various cytokines. In liver disease, bacterial infections have been associated with the impairment of liver metabolic function.

AIMS

To evaluate the influence of H. pylori infection on liver function as assessed by means of the monoethylglycinexylidide test, which depends upon liver blood flow and cytochrome P-450 activity, and the 13C-galactose breath test, which depends on cytosolic enzymatic activity and is correlated with hepatic functional mass. Moreover, to evaluate whether H. pylori-associated modifications of liver function may be related to tumour necrosis factor-alpha serum levels.

PATIENTS AND METHODS

Thirty-five patients with liver cirrhosis of various aetiologies, who underwent monoethylglycinexylidide and 13C-galactose breath tests, were retrospectively evaluated for H. pylori infection by means of anti-H. pylori immunoglobulin G. The main clinical, biochemical and functional characteristics of the patients as well as their tumour necrosis factor-alpha serum levels were then analysed on the basis of the presence of H. pylori infection.

RESULTS

Twenty-one patients tested positive for H. pylori infection (60%), and 11 tested negative (31.4%). No clinical or biochemical differences were observed between H. pylori-infected and non-infected patients. H. pylori infection showed no difference in distribution according to Child-Pugh classes (A, 55%; B and C, 67%). The monoethylglycinexylidide test results were significantly lower at each sampling time in H. pylori-positive patients compared to H. pylori-negative patients (MEGX15, P=0.027; MEGX30, P=0.014; MEGX60, P=0.028), while 13C-galactose breath test showed no significant differences considering both cumulative percentage dose and percentage dose/h. The median tumour necrosis factor-alpha serum levels were no different between H. pylori-positive (16.1 pg/mL, 95% confidence interval, 8.7-28.7) and H. pylori-negative (12.3 pg/mL, 95% confidence interval, 8.7-23.4) patients.

CONCLUSIONS

In cirrhotic patients, H. pylori infection seems to selectively affect cytochrome P-450 liver activity, while hepatic functional mass does not seem to be impaired. Tumour necrosis factor-alpha does not seem to be the mediator of this impairment. Further studies are needed to evaluate the impact of H. pylori eradication on parameters of liver function.

Liver iron accumulation in chronic hepatitis C patients without HFE mutations: relationships with histological damage, viral load and genotype and alpha-glutathione S-transferase levels

BACKGROUND

Host and viral factors have been suggested as possible causative factors for the presence of liver iron accumulation in chronic hepatitis C. However, there is no agreement regarding the influence of liver iron accumulation on the biochemical and histological severity of chronic hepatitis C. Moreover, data concerning the relationships between both viral load and genotype and liver iron accumulation are scanty.

AIMS

To evaluate the biochemical, histological and virological assessment of a group of chronic hepatitis C patients without risk factors for iron overload, on the basis of the presence, degree and distribution of liver iron accumulation.

METHODS

Fifty-three chronic hepatitis C patients (34 men, 19 women; age 44 +/- 11 years) with no risk factors for liver iron accumulation and showing no HFE mutations were chosen from a broader cohort of chronic hepatitis C patients. The presence, degree and distribution of liver iron accumulation were assessed using Deugnier's score. Relationships between the presence of liver iron accumulation and grading and staging were carried out separately. Hepatitis C virus RNA serum levels and viral genotype were compared in patients with or without liver iron accumulation. Alpha glutathione S-transferase serum levels were assessed in all patients.

RESULTS

Overall, liver iron accumulation was mild and was present in 19 patients (36%). It was associated with male gender (P = 0.0358), and was reflected by high serum iron levels (P = 0.001) and high ferritin levels (P < 0.0001). Hepatitis C virus RNA levels and genotype were not associated with the presence of liver iron accumulation. In multivariate analysis, ferritin was the only variable significantly associated with liver iron accumulation (P < 0.0001). Grading was higher in patients with liver iron accumulation regardless of the site of iron deposition. Fibrosis was present in all patients with iron overload; these patients were more frequently cirrhotic. Moreover, patients with mesenchymal or mixed deposition had higher staging than patients with hepatocytic or no iron deposition. This feature was reflected by higher alpha-glutathione S-transferase levels.

CONCLUSIONS

Liver iron accumulation is mild in chronic hepatitis C patients without HFE mutations and is mainly reflected by serum ferritin levels. Viral characteristics do not seem to play a role in iron deposition. Liver iron accumulation is associated with higher grading, advanced fibrosis and cirrhosis. Moreover, higher staging is associated with mesenchymal or mixed iron deposition. In these patients, higher alpha-glutathione S-transferase levels seem to reflect more complex damage.

Single-particle dynamics in collisionless magnetic reconnection

The role of single-particle dynamics in driven magnetic reconnection in collisionless plasmas is investigated experimentally and analytically. The trapping of particle orbits in the magnetic cusp is observed to allow fast reconnection in the absence of a macroscopic current layer, at a rate identical to that of vacuum. The development of an electrostatic potential structure around the magnetic X line during reconnection is predicted theoretically and observed experimentally.

Long-term follow up of chronic hepatitis C patients after alpha-interferon treatment: a functional study

AIM

To evaluate the long-term functional outcome of chronic hepatitis C (CHC) patients treated with interferon (IFN) therapy.

METHODS

Thirty-six patients with CHC were followed up for a mean of 36 months (+/- 19, SD) after a course of IFN therapy. Biochemical, virological (qualitative hepatitis C virus (HCV)-RNA and HCV genotype), and functional (monoethylglycinexylidide (MEGX) test) evaluations were carried out at the time of liver biopsy. Patients were divided into long-term responders (LTR), relapsers (RR), or non-responders (NR) according to IFN therapy outcome. At the end of follow up, patients were non-invasively re-evaluated by means of biochemistry, qualitative HCV-RNA, MEGX test, and liver ultrasonography.

RESULTS

A significant decrease in MEGX values was observed in all patients. However, when patients were examined according to treatment outcome, only NR and RR showed a significant decrease in liver function as compared to pretreatment levels (MEGX30, 80.5 +/- 26.8-62.9 +/- 24.2 ng/mL, P< 0.01; MEGX60, 72.9 +/- 18.1-60.5 +/- 19.7 ng/mL, P< 0.05; MEGXAUC, 3,816 +/- 1,243-3,095 +/- 1,205 ng/mL per h, P< 0.05). On the contrary, LTR patients showed no significant modifications in MEGX values at each sampling time (MEGX,5, 72.9 +/- 31.4-70.3 +/- 29.7 ng/mL; MEGX30, 84.0 +/- 27.6-71.5 +/- 21.8 ng/ mL; MEGX60, 69.5 +/- 26.8-63.2 +/- 14.4 ng/mL; MEGXAUC 4028 +/- 1,378-3,620 +/- 1,041 ng/mL per h). At the end of follow up, LTR patients showed normal liver biochemistry and negativity of serum HCV-RNA, while NR and RR patients showed a significant decrease in platelets.

CONCLUSIONS

In CHC patients long-term response to IFN therapy, besides favoring positive clinical and virologic long-term outcome, results in maintaining preserved liver function. Furthermore, IFN therapy seems to determine a decrease in the rate of functional disease progression, even in NR and RR. The MEGX test may be considered as a useful tool for performing serial follow up of CHC patients.

Increased levels of gammaGT suggest the presence of bile duct lesions in patients with chronic hepatitis C: absence of influence of HCV genotype, HCV-RNA serum levels, and HGV infection on this histological damage

Damage to bile ducts in chronic hepatitis C is a characteristic histological lesion. Moreover, the presence of abnormal levels of gammaGT in these patients is also a common finding. Assessing whether the presence of bile duct lesions is indicated by biochemical abnormalities or whether virological characteristics can influence their development may help in the definition of clinical-histological relationships in chronic hepatitis C. In this study we evaluated the relationships among routine biochemical parameters, serum bile acids, and pi-class glutathione S-transferase levels, and the presence of bile duct lesions in 60 patients with chronic hepatitis C. Furthermore, we assessed whether the presence of bile duct lesion might be related to HCV genotype, HCV-RNA serum levels, and positivity for HGV-RNA. We found that gammaGT was the only parameter related to the presence of bile duct lesions. Although a trend towards higher serum bile acids and pi-class glutathione S-transferase levels was observed in patients with bile duct lesions, this trend did not reach statistical significance. Different HCV genotypes and RNA levels, and HGV-RNA positivity did not seem to influence the presence of bile duct damage. In conclusion we found that gammaGT levels point out the presence of bile duct lesions in patients with chronic hepatitis C. Since we observed a different pattern of alteration of gammaGT, serum bile acids, and pi-class glutathione S-transferase, we suggest that these various biochemical alterations reflect a more complex damage to bile duct structures, which is not likely represented by the common assessment of bile duct lesions. Viral factors such as HCV genotype and RNA levels as well as HGV-RNA positivity are probably not the main cause of this histological damage.

Influence of Helicobacter pylori eradication therapy on 13C aminopyrine breath test: comparison among omeprazole-, lansoprazole-, or pantoprazole-containing regimens

OBJECTIVE

Proton pump inhibitors and antimicrobial agents are widely used to eradicate Helicobacter pylori (H. pylori) infection. In the general population the prevalence of infection and of polypharmacy increases the possibility of drug-drug interactions during H. pylori eradication therapy. The purpose of the present study was to assess the prevalence, degree, and clinical relevance of metabolic interference with the cytochrome P450 enzymatic system occurring during 1 wk of administration of omeprazole, lansoprazole, or pantoprazole followed by the association of clarithromycin and metronidazole for another week. The 13C aminopyrine breath test (ABT) was chosen to screen for possible interactions.

METHODS

We studied 30 patients referred to our Unit for H. pylori eradication therapy. They were randomized to receive either omeprazole (20 mg b.i.d.), lansoprazole (30 mg b.i.d.), or pantoprazole (40 mg b.i.d.) for 2 wk. During the second week clarithromycin (250 mg b.i.d.) and metronidazole (500 mg b.i.d.) were added. ABT was performed before, and at the end of the first and second week of therapy. Percentage of the administered dose of 13C recovered per hour at the peak (percent 13C dose/h at the peak) and cumulative percentage of administered dose of 13C recovered over time at 120 min (percent 13C dose cum120) were the ABT evaluated parameters.

RESULTS

At baseline all patients showed a normal liver function. In individual patients during treatment we observed various liver metabolic interactions both as inhibition and induction, as well as after the first and the second week of therapy. However, mean modifications of the ABT parameters during the 2 weeks of therapy were not statistically significant compared to baseline values. None of the patients who had ABT variations complained of side effects.

CONCLUSIONS

H. pylori eradication therapy interferes with cytochrome P450-dependent liver metabolic activity. However, the clinical relevance of these metabolic interactions is not yet apparent, and further investigation is needed. H. pylori eradication therapy appears safe, but these interactions should be considered in the choice of proton pump inhibitor and antimicrobial agents.

Does surveillance for hepatocellular carcinoma in HCV cirrhotic patients improve treatment outcome mainly due to better clinical status at diagnosis?

BACKGROUND/AIMS

Cirrhotic patients with hepatitis C virus infection are a group at higher risk for hepatocellular carcinoma. Conventional screening programs detect only few early hepatocellular carcinomas that are eligible for radical treatment. Our aim was to compare characteristics of patients, modality of treatment, and outcome in anti-HCV positive cirrhotics with hepatocellular carcinoma diagnosed during follow-up, or incidentally.

METHODOLOGY

Sixty-one hepatocellular carcinomas were consecutively diagnosed in cirrhotic anti-HCV patients from 1993-1998 among which 34 during biannual ultrasonographic-biochemical follow-up and the others incidentally. Child-Pugh's score, alpha-fetoprotein levels, uni- or multifocality of the tumor, and treatment and survival of the patients were then analyzed on the basis of modality of diagnosis.

RESULTS

Surgical treatment was feasible only in a minority of patients. Radical and palliative treatment was more frequent among patients with HCC diagnosed during follow-up. Child-Pugh's score was lower in these patients, moreover their survival rate was better. Analysis of survival of patients treated with the same procedure and grouped by modality of diagnosis did not demonstrate any differences. Regression analysis showed that patients with a lower Child-Pugh's score, one nodule, with a tumor diagnosed during follow-up and who were treated had a better survival rate.

CONCLUSIONS

In our population surveillance did not detect a higher percentage of curable HCC. Nevertheless the results of palliative treatment and of curative treatment overlapped. Overall better outcome was observed in patients with preserved liver function whatever the treatment. Surveillance allowed us to diagnose HCC in patients with these characteristics thus leading to an improved survival rate.

The monoethylglycinexylidide test does not impair psychometric performance in patients with chronic hepatitis or cirrhosis

Lidocaine (LID) is an aminoethylamide used in hepatology to perform the monoethylglycinexylidide (MEGX) test for the evaluation of liver function in patients with cirrhosis (CIR) or chronic hepatitis (CH). The authors evaluated whether the MEGX test changes psychometric performance in patients with chronic liver disease and, in particular, whether it might trigger subclinical portosystemic encephalopathy in patients with CIR. Thirty patients with CIR and 20 patients with CH were studied. They underwent a standard-dose MEGX test, before and after which a psychometric test was administered and blood pressure, heart rate, and adverse effects were recorded. The MEGX test did not modify psychometric performance. Mean arterial blood pressure and heart rate did not change at the end of the MEGX test in either patients with CH or CIR. Adverse effects were present in 66% of all patients during lidocaine injection and lasted up to 3 minutes afterwards. They were more frequent in patients with CH than in patients with CIR (85% vs 53%). No relationship was found between adverse effects and lidocaine dosage, nor between adverse effects and MEGX or lidocaine concentration at 15 minutes. Standard-dose MEGX test does not worsen or trigger portosystemic encephalopathy in CIR. Adverse effects were frequent but mild.

Histologic determinants of monoethylglycinexylidide formation in patients with chronic hepatitis C

Patients affected by chronic hepatitis C (CHC) display a peculiar histologic picture characterized by the presence of steatosis and bile duct damage in addition to evidence of inflammation, necrosis, and fibrosis. In the staging of these patients, functional evaluation may be considered a complementary tool. The monoethylglycinexylidide (MEGX) test has been used in diagnostic and prognostic assessment of chronic liver disease as a quantitative liver function test. In this study the authors evaluated whether different sampling times for the test could reflect different histologic patterns. The authors studied 82 patients with biopsy-proven CHC who underwent functional evaluation by means of MEGX test. The authors found that MEGX15 better reflected the histologic findings of necrosis and inflammation, and MEGX60 the presence of fibrosis. Neither steatosis nor bile duct damage showed a strong correlation with either sampling time. Moreover, MEGX levels showed a progressive decrease as histologic grading of chronic hepatitis progressively increased. Stepwise regression analysis identified necrosis and inflammation as histologic variables associated with both MEGX15 and MEGX30, and fibrosis as a variable associated with MEGX60. These results suggest that a decline in liver metabolic function corresponds to a progressive increase in liver damage, and that this circumstance should be taken into account when prescribing drugs to patients with CHC.

Serum leptin levels in patients with viral chronic hepatitis or liver cirrhosis

BACKGROUND/AIM

Serum levels of leptin, the adipocyte-derived hormone regulating food intake and energy expenditure in mammals, have been found to be increased in cirrhotic patients. The aim of the present study was to investigate leptin serum level in relation to anthropometric features and liver function in patients with viral chronic hepatitis or liver cirrhosis.

METHODS

Serum leptin levels were determined by radioimmunoassay in 30 male and 10 female patients with chronic hepatitis, in 42 male and 10 female patients with liver cirrhosis, and in four respective control groups. Liver function was evaluated by the monoethylglycinexylidide formation test. Body mass index and body fat mass were estimated by weight, height and skinfold thickness measurements.

RESULTS

Compared with controls, absolute serum leptin levels were significantly (p<0.01) lower in chronic hepatitis patients and similar in cirrhotic patients. Leptin serum levels were significantly (p<0.05) higher in cirrhotic than in chronic hepatitis patients. When expressed in relation to body fat mass, the above differences persisted; however, cirrhotic females showed significantly (p<0.05) higher serum leptin values than controls. Serum leptin values correlated negatively (p<0.01) with monoethylglycinexylidide serum values in all groups of patients.

CONCLUSIONS

In patients with chronic viral liver disease, serum leptin levels tend to increase as liver function worsens. This may reflect a decline in the ability to downregulate energy expenditure as an adaptation to anorexia and/or to defective substrate utilisation due to liver disease and may negatively influence body weight homeostasis in these patients.

Utility of alpha-glutathione S-transferase assessment in chronic hepatitis C patients with near normal alanine aminotransferase levels

OBJECTIVES

To study whether determining alpha-glutathione S-transferase (alpha-GST) might improve the assessment of chronic hepatitis C (CHC) patients with near normal alanine aminotransferase levels (NNA).

DESIGN AND METHODS

We studied 119 viraemic CHC patients. They were subdivided into two groups according to the pattern of alanine aminotransferase (ALT) alteration, i.e. consistently above (HA) or below (NNA) twice the upper normal value. In these patients we assessed alpha-GST and correlated its levels to clinical, histological, and virological findings, further evaluating whether alpha-GST might improve the assessment of CHC patients with NNA.

RESULTS

alpha-GST showed a significant correlation with aminotransferases, though not with histological necroinflammatory activity and fibrosis or with hepatitis C virus RNA levels. Twenty-seven patients had NNA (23%), and within this subgroup of patients alpha-GST identified a subset of patients with a higher viral load.

CONCLUSIONS

alpha-GST in CHC patients is related to hepatocellular necrosis parameters, but unrelated both to histology and to viraemia. However, in patients with NNA, alpha-GST identified a subgroup of patients with a higher viral load. In this subgroup of patients alpha-GST alteration likely represents the expression of a more severe damage. Because this injury is not detectable by the usual biochemical or histological work-up, we suggest that alpha-GST could a useful tool for monitoring liver damage over time.

13CO2 excretion in breath of normal subjects and cirrhotic patients after 13C-aminopyrine oral load. Comparison with MEGX test in functional differentiation between chronic hepatitis and liver cirrhosis

BACKGROUND/AIMS

Liver function can be evaluated using 13C breath tests that explore liver Cytochrome P450 activity. Aminopyrine is one of the first compounds used in liver function testing. Lidocaine metabolism to monoethylglycinexylidide is also a valid tool to assess liver function. Although liver Cytochrome P450 metabolizes both compounds, lidocaine metabolism is flow-dependent while aminopyrine metabolism does not depend on liver blood flow.

METHODOLOGY

The 1st part of the study evaluated the appearance and disappearance rate of 13CO2 in the breath of both normal subjects and in cirrhotic patients, so as to establish optimal sampling times and to evaluate the amount of time needed before performing a subsequent breath test. The 2nd part of the study compared the aminopyrine breath test with the monoethylglycinexylidide test in patients with chronic hepatitis or cirrhosis.

RESULTS

Complete 13CO2 disappearance was recorded 24 hours after the test in normal subjects, while it took 3 days to disappear from the breath of cirrhotic patients. Breath sampling at 60, 120 and 180 min were equally valid in differentiating chronic hepatitis from cirrhosis. The aminopyrine breath test and monoethylglycinexylidide test showed a good yet not close correlation.

CONCLUSIONS

This study showed that in cirrhotic patients a 13C breath test can be performed 3 days after the previous one. In chronic hepatitis and cirrhotic patients, the aminopyrine breath test and the monoethylglycinexylidide test evaluated similar, but not identical, hepatic subfunctions, suggesting that multiple 13C breath test using different substrates could explore liver function better.

Steatosis and bile duct damage in chronic hepatitis C: distribution and relationships in a group of Northern Italian patients

BACKGROUND/AIMS

Hepatitis C virus (HCV) related disease follows a long, benign course and most affected patients have mild disease. Liver biopsy is mandatory to grade and stage the disease. Characteristic, though non-specific, HCV histological lesions such as bile duct damage and steatosis have been singled out but their association with non-histological parameters has not been completely defined. Our aim was to study the relationships among these histological lesions and clinical, biochemical, functional and virological characteristics in a group of Northern Italian patients with chronic hepatitis.

METHODS

We studied 172 patients with HCV-related chronic hepatitis. Patients were divided into groups on the basis of histology including bile duct damage and steatosis. Clinical, biochemical, functional and virological profiles were related to histological findings.

RESULTS

Histological grading and staging of disease increased as the age of patients increased. Steatosis was present in 70% of our patients and was related to a higher degree of fibrosis and to decreased functional activity. The prevalence of bile duct damage was 20%. This lesion was present in older patients with higher staging and impaired liver function. Biochemically it was associated with an increase in aspartate aminotransferase, gammaglutamyltranspeptidase, alkaline phosphatase, and total bilirubin.

CONCLUSIONS

In the population we studied, HCV chronic hepatitis was predominantly a mild disease. Moreover both steatosis and bile duct damage were also mild. Steatosis was associated with fibrosis and this might influence liver metabolic function. Bile duct lesions were found in older patients with advanced disease showing biochemical evidence ofcholestasis. The molecular role HCV might play in the pathogenesis of these histological features should be addressed in further studies.