Philippe Thiry

The predictive value of FIB‐4 versus FibroTest, APRI, FibroIndex and Forns index to noninvasively estimate fibrosis in hepatitis C and nonhepatitis C liver diseases

Noninvasive indirect biochemical markers of liver fibrosis have gained popularity, but hepatologists are now facing the difficult dilemma of choosing among the 20 fibrosis markers that are now available.1 Stanislas Pol’s group2 claim that FIB-4, initially developed in a human immunodeficiency virus (HIV)-hepatitis C virus (HCV) coinfected population, is a simple, inexpensive, and readily available marker which is reliable for predicting fibrosis in HCV monoinfected patients. It combines platelets, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and age as measurement factors. However, they did not present comparative area under the receiver operating characteristic curves (AUROCs) with other inexpensive, simple, and readily available scores such as APRI (aspartate aminotransferase-to-platelet ratio index), Forns index, FibroIndex, and FibroTest, which have been widely validated in the HCV3-5 and non-HCV population.6-8 They do not provide data for other liver diseases besides HCV and, finally, they do not give data related to the value of FIB-4 for the prediction of significant (Metavir F2-4 or Brunt S2-4) fibrosis, another important issue for the clinician because this is the cut-off above which progression of fibrosis occurs and medical treatment is needed. We sought to compare, independently from the promoters, the diagnostic accuracy using AUROCs of the 5 biochemical scores in our HCV population (n 152) and our global series (n 290) of patients with chronic liver disease including also hepatitis B virus (n 16), alcoholic (n 54), nonalcoholic (n 38), and other (n 23) diseases. The prevalence of significant fibrosis (F2-4 or S2-4), advanced fibrosis (F3-4 or S3-4), and cirrhosis (F4 or S4), evaluated histologically using the METAVIR (in the HCV, HBV, and other populations) or the BRUNT classification (in alcoholic and nonalcoholic liver disease) was 77%, 23%, and 12% and 77%, 34%, and 21%, respectively, in the HCV series and the global series. This compares to 36%, 17%, and 7% in Pol’s HCV series. Comparing the performance of the 5 tests in our HCV and global series for the diagnosis of significant fibrosis, advanced fibrosis, and cirrhosis (Table 1), FibroTest and FIB-4 have equal excellent diagnostic power, FibroIndex being the least accurate. Table 1 and Fig. 1 show a trend for FibroTest to have better AUROCs, even if they are not statistically significant. In the global series, the Forns index is less accurate than FibroTest and FIB-4 for the diagnosis of cirrhosis and APRI also has less discriminative power than FibroTest and FIB-4 for the diagnosis of significant fibrosis, advanced fibrosis, and cirrhosis. Thus, the results of our study reinforce the last recommendations9 of the HAS (Haute Autorité de la Santé) in France, which equally ranked the following methods for the diagnosis of liver cirrhosis: liver biopsy, Fibroscan, and FibroTest. Our data are in accordance with those of Pol’s group2 and confirm, in a HCV series where the prevalence of advanced fibrosis is similar, that FIB-4 is an alternative to FibroTest albeit with less expense for 3 clinically pertinent issues: the noninvasive diagnosis

Prognostic evaluation of patients with parenchymal cirrhosis. Proposal of a new simple score

BACKGROUND/AIMS The current shortage of organs makes it desirable to establish the prognosis of patients with cirrhosis in order to assess priority for liver transplantation. METHODS We compared the utility of two exogenous tests (aminopyrine breath test and lidocaine metabolization test), two clinical parameters (encephalopathy, ascites), 18 endogenous tests and five scores (Pugh, Merkel, Orrego, Adler, Pignon) for predicting 1-year mortality in patients with parenchymal cirrhosis. Retrospective (n=49 out of 63 patients) and prospective (n=38 out of 46 patients) series were included. Univariate, multivariate, receiver operator curves and survival curves were employed. RESULTS We found that endogenous tests were more discriminant than exogenous tests. The best parameters of the univariate analysis (encephalopathy, bilirubin, alkaline phosphatase, cholinesterase and bile acids) and their 25th and 75th percentiles were included in an additive new score which turned out to be superior to the five other scores. Prospectively, the sensitivity of our new score compared to the Pugh score was 82% versus 95% (NS) and the specificity was 89% versus 56% (p<0.01). CONCLUSIONS Our new simple score appears to be very powerful for predicting prognosis at 1 year for patients with cirrhosis and should be evaluated in other centers.

Trypsin activity : a new marker of acute alcoholic pancreatitis

A normal serum amylase level is found in up to 32% of patients with acute alcoholic pancreatitis. This underlines the need for more sensitive diagnostic tests in this frequent cause of pancreatitis. Animal and human studies have shown that chronic alcohol consumption leads to important modifications in trypsinogen metabolism. The present work has prospectively analyzed admission serum trypsin activity with a new biochemical test and usual markers such as amylase, lipase, and immunoreactive trypsin in 32 attacks of acute pancreatitis. Seventeen were due to alcohol and 15 to other causes, including 11 with gallstone pancreatitis. High trypsin activity (median: 235 units/liter; range: 165–853) was found in all patients with acute alcoholic pancreatitis even when the amylase level was normal on admission (3/17: 18%). Trypsin activity did not differ between nonalcoholic pancreatitis (N=15): 84 units/liter (42–98), alcoholic controls (N=15): 77 units/liter (40–122), and healthy controls (N=62): 81 units/liter (15–143). The difference was not related to the severity of disease or circulating α2-macroglobulin, α1-protease inhibitor, or immunoreactive trypsinogen levels. Lipase/amylase ratio was less discriminant than trypsin activity between alcoholic and nonalcoholic diseases. We conclude that serum trypsin activity seems specific to acute alcoholic pancreatitis and should be included in new prospective studies assessing biochemical testing of alcohol-related pancreatic diseases.

Evaluation of a new generation of plastic evacuated blood-collection tubes in clinical chemistry, therapeutic drug monitoring, hormone and trace metal analysis.

Abstract Polyethylene terephthalate (PET) tubes have several advantages over glass tubes: they are unbreakable, lighter and more easily disposed of. Despite a steady increase in their use and an expansion of the range of available tubes, few studies validating their use have been published in the literature. This paper describes the various studies that have been performed to compare VENOJECT glass, VENOSAFE PET and VENOSAFE PET/heparin tubes for the assay of a panel of analytes in routine clinical chemistry, immunochemistry, hormone and tumor marker analysis and trace metal determination. These studies demonstrate that VENOSAFE PET tubes are a suitable alternative to glass tubes.

Measurement of soluble transferrin receptor by immunoturbidimetry and immunonephelometry.

OBJECTIVE To evaluate and compare two new commercially available immunoturbidimetric and immunonephelometric assays for measuring soluble transferrin receptor (sTfR) in serum. To adapt the immunonephelometric assay to an automated chemistry analyzer. DESIGN AND METHODS Total imprecisions and detection limits were calculated and compared. Fifty-six samples were used for methods comparison. The nephelometric assay was adapted to the Hitachi 911 analyzer. RESULTS Both methods displayed acceptable imprecisions and detection limits. Their correlation was good but a proportional bias was observed. The adaptation of the nephelometric assay to the Hitachi 911 was successful. CONCLUSIONS These two new immunoassays are analytically acceptable and more practicable than previously developed methods. The differences observed between both methods underscores the need for standardization. The nephelometric assay was easily adaptable to an automated chemistry analyzer.

Whole blood cyclosporin monitoring in liver and heart transplant patients: evaluation of the specificity of a fluorescence polarization immunoassay and an enzyme-multiplied immunoassay technique

The specificity of two cyclosporin immunoassays were evaluated. Eleven patients were followed for the first four weeks after heart (n = 3) or liver (n = 8) transplantation. Cyclosporin A (CsA) monitoring was performed concomitantly by a monoclonal fluorescence polarization immunoassay (mFPIA) and enzyme-multiplied immunoassay technique (EMIT) during this period. For several patients, cyclosporin monitoring was also performed by high performance liquid chromatography (HPLC) or by polyclonal fluorescence polarization immunoassay (pFPIA). Liver function was assessed by follow-up of plasma total bilirubin, gamma-glutamyl transferase and alkaline phosphatase and renal function by plasma creatinine. All the patients presented episodes of impaired liver function. Higher CsA levels were found using mFPIA measurements as compared to the EMIT measurements (ratio mFPIA:EMIT (medium range) = 1.4 (1.0-2.3)). A higher degree of cross-reactivity of the antibody used in the mFPIA as compared to the EMIT was demonstrated by specific measurements of CsA and its primary metabolite, AM1, by HPLC.

Reference Intervals for Plasma Homocysteine by the AxSYM Immunoassay after Collection in Fluoride Tubes

Homocysteine (HCy) is an intermediate amino acid formed during the metabolism of methionine to cysteine. In the recent years, it has emerged as a risk factor for cardiovascular disease independent of known other factors (1)(2)(3). The first methods developed for total plasma HCy measurements were HPLC, with or without derivatization, and gas chromatography. Later, immunoassays were developed, allowing automation and widespread use of the marker in the medical world. Plasma HCy is influenced by various factors: genetics, diet, sex, age, ethnic group, drugs, and diseases. EDTA-, citrate-, or heparin-anticoagulated blood may be used, but plasma should be immediately separated from blood cells to avoid spurious increases (4). Addition of different substances has been suggested to reduce these spurious increases in HCy concentrations. Acidic citrate has been shown to be effective in some studies (5) but not in others (6). A specific inhibitor of S -adenosylhomocysteine hydrolase (3-deaza-adenosine) was successfully used, but unfortunately, it is not compatible with immunoassays (7). Fluoride appears to be the most interesting additive. Ubbink et al. (8) showed that it prevents in vitro increases for 2 h. Several studies have confirmed this effect (9), although others have not (10). In most studies, plasma HCy from blood collected in fluoride tubes has been lower than in EDTA tubes (10)(11)(12). Our aim was to evaluate the protective effect of fluoride against spurious increases of in vitro HCy and to establish reference intervals for the AxSYM immunoassay (Abbott) for plasma HCy from blood collected into fluoride tubes. The …

Utilization of waste cellulose—III. Comparative study of the activity of the cellulases of Trichoderma viride and Aspergillus niger towards different cellulosic substrates☆

Abstract Filter paper, carboxymethylcellulase and β-glucosidase activities have been determined and compared for cellulases originating from Trichoderma viride (TV) and Aspergillus niger (AN). The formation of glucose and of total reducing sugar has been measured as a function of time for the hydrolysis of cellulose I by the same quantity of FP units from TV, AN or a mixture of both strains. Long term efficiency is lower for AN but an important synergistic effect has been observed for the mixture of the enzymes. This synergistic action has been assigned to a better balance of endo- and exoglucanases and essentially to the addition to TV of thermally stable endoglucanases from AN. The β-glucosidases formed in large quantity by AN have been found to be thermally unstable and susceptible to product inhibition. They do not play any role in the observed synergistic action.

Utilization of waste cellulose-V comparative effects of different pretreatments on the enzymatic hydrolysis of cellulose and ligno-cellulosic substrates

Abstract Pretreatments based on the oxidation of cellulose and ligno-cellulosic materials by sodium hypochlorite are compared with classical pretreatments ( Fe 2+ H 2 O 2 , γ-rays, concentrated and dilute NaOH, Cadoxen, mechanical pulping). Substrates studied are paper pulp, wheat straw and spruce wood. The importance of oxidation and of transformation of cellulose I into cellulose II are discussed. Pretreatment of spruce wood by NaClO gives yields of glucose during enzymatic hydrolysis which compare very favourably with those obtained with the more expensive cadoxen and concentrated NaOH treatments. High yields of glucose are also obtained in the case of bagasse and barley straw. The work has been extended to other halogenated oxidizing agents.

Utilization of waste cellulose. VI: Pretreatment of lignocellulosic materials with sodium hypochlorite and enzymatic hydrolysis by trichoderma viride

A pretreatment of lignocellulosic materials with sodium hypochlorite-hypochlorous acid at controlled pH (between 7 and 9) considerably increases the accessibility of the cellulosic part of the substrate to chemical and biochemical reactants. As a consequence, the yield and rate of the enzymatic hydrolysis to glucose is largely in creased. Wheat straw and spruce sawdust have been investigated. The increase in accessibility is assigned to degradation and (or) de tachment of the lignin network. The loss in cellulose and hemicellulose is not important, lignin being preferentially degraded under carefully controlled pH conditions. When applied to pure cel lulose, the pretreatment decreases the yield of enzymatic hydrolysis; in the absence of lignin, oxidation of the anhydroglucose units is im portant and results in the inhibition of the enzymatic hydrolysis.