Biomarker-based prognosis in hepatocellular carcinoma: validation and extension of the BALAD model.

BACKGROUND: The Japanese 'BALAD' model offers the first objective, biomarker-based, tool for assessment of prognosis in hepatocellular carcinoma, but relies on dichotomisation of the constituent data, has not been externally validated, and cannot be applied to the individual patients. METHODS: In this Japanese/UK collaboration, we replicated the original BALAD model on a UK cohort and then built a new model, BALAD-2, on the original raw Japanese data using variables in their continuous form. Regression analyses using flexible parametric models with fractional polynomials enabled fitting of appropriate baseline hazard functions and functional form of covariates. The resulting models were validated in the respective cohorts to measure the predictive performance. RESULTS: The key prognostic features were confirmed to be Bilirubin and Albumin together with the serological cancer biomarkers, AFP-L3, AFP, and DCP. With appropriate recalibration, the model offered clinically relevant discrimination of prognosis in both the Japanese and UK data sets and accurately predicted patient-level survival. CONCLUSIONS: The original BALAD model has been validated in an international setting. The refined BALAD-2 model permits estimation of patient-level survival in UK and Japanese cohorts.

A collaborative study for the evaluation of lectin-reactive alpha-fetoproteins in early detection of hepatocellular carcinoma.

Lectin-affinity electrophoretic separation of serum alpha-fetoprotein (AFP) was carried out using AFP Differentiation Kits, which used Lens culinaris agglutinin-A (Kit L) and erythroagglutinating phytohemagglutinin (Kit P). Separated AFP bands were detected with a sensitive antibody-affinity blotting technique and determined quantitatively by densitometry, and the results were expressed as percentages of the intensity of total AFP bands. Sera from 424 patients with acute hepatitis, chronic hepatitis, liver cirrhosis, hepatocellular carcinoma, and extrahepatic tumors were assayed for proportion of AFP present as Lens culinaris agglutinin-A-reactive AFP (AFP-L3) and erythroagglutinating phytohemagglutinin-reactive AFPs (AFP-P4+P5). From the maximum Youden indices determined, cutoff levels were set at 15% for both AFP-L3 and AFP-P4+P5 to discriminate between patients with chronic hepatitis and liver cirrhosis and patients with hepatocellular carcinoma. AFP-L3 and AFP-P4+P5 showed sensitivities of 55.3 and 61.0% at specificities of 93.9% and 82.3%, respectively. Thirty-eight % of tumors that measured less than 20 mm in diameter were positive for AFP-L3 and AFP-P4+P5. AFP-L3 exceeded the cutoff level of 15% 4.0 +/- 4.9 months before detection of hepatocellular carcinomas by imaging techniques with a sensitivity of 48% and a specificity of 81%. Thus, these tests are useful for the early detection of hepatocellular carcinomas in patients with hepatitis or liver cirrhosis.

Structural characteristics of the N-glycans of two isoforms of prostate-specific antigens purified from human seminal fluid.

Prostate-specific antigen (PSA) is a glycosylated chymotrypsin-like serine protease and is found mainly in prostatic tissue and seminal fluid. We purified two forms of PSA (PSA-A and PSA-B) from human seminal fluid with pI values of approx. 7.2 and approx. 6.9, respectively. To characterize the N-glycans of the two isoforms, the sugar chains were liberated by hydrazinolysis followed by N-acetylation, and derivatized with 2-aminobenzamide. Both PSA-A and PSA-B contained mono- and disialylated sugar chains, although PSA-B had a much higher content of the latter. After removal of sialic acid residues by sialidase digestion, mono- and biantennary N-glycans and three outer chain moieties (Galbeta1-4GlcNAcbeta1-, GlcNAcbeta1-, GalNAcbeta1-4GlcNAcbeta1-) were found in both samples. However, the ratios of each N-glycan were different. These results indicate that PSA-A and PSA-B differ not only in their sialic acid contents, but also in their outer chain features.

Determination of alpha-fetoprotein concentration based on liquid-phase binding assay using anion exchange chromatography and sulfated peptide introduced antibody.

A new immunoassay for alpha-fetoprotein based upon liquid-phase binding reactions is described. In this procedure, a sample that contains alpha-fetoprotein is mixed with a solution of two anti-alpha-fetoprotein monoclonal antibodies complexed with peroxidase and sulfated peptide, respectively. After incubation, immune complex is separated from other components by anion exchange column chromatography. Immune complex is quantified using fluorometric detection by peroxidase enzymatic activity. Peroxidase activity correlated with a alpha-fetoprotein with a 1:1 relationship. The stoichiometric immunoreaction allowed a large analytical range (0.4-7500 ng/ml) with a linear dose-response relationship, high sensitivity and good precision. Endogenous substances did not interfere with assay performance. Assay results showed good correlation with other established methods. These results indicate that the method is useful for clinical alpha-fetoprotein determinations.

Evaluation of curability and prediction of prognosis after surgical treatment for hepatocellular carcinoma by lens culinaris agglutinin-reactive alpha-fetoprotein.

The clinical significance of serum lens culinaris agglutinin-reactive alpha-fetoprotein (AFP-L3), which can distinguish between hepatocellular carcinoma and hepatitis by detecting a sugar chain micro heterogeneity, was evaluated for its possible ability to recognize previously undetectable residual tumors, and for increasing the accuracy of prognosis after surgical treatment for hepatocellular carcinoma. Serum lens culinaris agglutinin-reactive alpha-fetoprotein was measured pre- and post-operatively in 130 patients who underwent curative surgical treatment for hepatocellular carcinoma. The preoperative AFP-L3 positive rate was 35.4%. AFP-L3 remained positive postoperatively in 28 of the 46 preoperative AFP-L3 positive patients, and converted to positive in 4 of the 84 preoperative AFP-L3 negative patients. Regardless to preoperative AFP-L3, the postoperative AFP-L3 positive patients had a poorer recurrence-free rate (p<0.0001). The postoperative L3 positive patients had a high incidence of recurrence due to metastasis, but did not have recurrence due to multicentric origin. Multivariate analysis revealed that AFP-L3 (p<0.0001) was the most independently significant factor for predicting survival after surgery among several conventional prognostic factors. Thus, AFP-L3 is a valuable marker for evaluation of curability of surgical treatment and for improving the accuracy of prognosis.

Analysis of lectin properties with membrane ultrafiltration and high-pressure liquid chromatography.

A convenient method for the analysis of the binding properties of lectin with fluorogenic sugar chains is described. A lectin (concanavalin A or Datura stramonium agglutinin) was mixed with pyridylaminated sugar chains in buffer and the free chains obtained were isolated by membrane ultrafiltration. The amount of free sugar chains in the filtrate was measured by high-pressure liquid chromatography. The binding constants with the sugar chains, reaction kinetics, and other properties of these lectins were easily investigated. The method is simple and could be used to study the characteristics of any lectin in native form.

Analytical method for sugar chain structures involving lectins and membrane ultrafiltration.

A simple and rapid analytical method for the structural identification of sugar chains involving lectins and ultrafiltration was developed. In the procedure, a mixture of fluorogenic sugar chains is mixed with an unmodified lectin. Unbound sugar chains are removed by ultrafiltration. Qualitative differences between sugar chains from the sample and from the filtrate were determined by high performance liquid chromatography. The structures of different sugar chains could be determined from the specificity of the lectins used. Because the lectins used for the procedure were not modified, both the lectins used and sugar chains could be recovered. The method is simple and can be used for structural analysis of sugar chains.

Identification of the active site of human renin with use of new fluorogenic peptides.

Fluorogenic peptide substrates were synthesized in which amino acid residues corresponded to the C-terminal and the N-terminal sides of the site of human angiotensinogen cleaved by renin. Compared with the synthetic substrates of renin previously reported, these fluorogenic substrates had practical advantages in that their digestion products could be rapidly separated and sensitively detected by high-pressure liquid chromatography with a fluorescence detector. The recombinant human renin and human plasma split Leu-Val, which cleavage site is similar to that in human angiotensinogen. The kinetic parameters of the reaction of renin using these substrates were calculated. There seemed to be at least eight subsites in the active site of recombinant human renin, to judge from the enzyme-substrate binding characteristics. The two histidine residues (S5 and S'3) in the octapeptide His-Pro-Phe-His-Leu-Val-Ile-His were important in the enzyme action.

Paradoxical weight loss with extra energy expenditure at brown adipose tissue in adolescent patients with Duchenne muscular dystrophy.

We examined the energy expenditure in patients with Duchenne muscular dystrophy(DMD) to evaluate the cause of the paradoxical weight loss observed in large numbers of adolescent patients before any obvious impairment of their swallowing function. In the morning, resting energy expenditure (REE)/m(2) was almost the same as that in normal controls despite a reduction in fat-free mass (FFM); thus, REE/m(2)/FFM was significantly increased in patients (median, 21.2 kcal/m(2)/FFM kg; range, 17.7 to 44.2, P =.012). A thermographic examination in the morning showed an obvious elevation of the body surface temperature on the back. This phenomenon was consistent with a paradoxical fall in the low frequency (LF)/high frequency (HF) ratio at night analyzed using the inter-RR spectrum by 24-hour electrocardiogram, which indicated relative activation of the sympathetic nervous system. The urinary secretion of norepinephrine at night was also significantly greater in patients (median, 0.119 microg/kg/h; range, 0.061 to 0.219, P =.011). These results suggest that paradoxical activation of the sympathetic nervous system may accelerate the production of heat in brown adipose tissue (BAT) and increase the level of energy consumption in patients, and that adolescent DMD patients may require greater caloric intake than expected to maintain body weight, which is important to improve the prognosis of their respiratory function.

AFP-L3: a new generation of tumor marker for hepatocellular carcinoma.

BACKGROUND: Alpha-fetoprotein (AFP) from hepatocellular carcinoma (HCC) displays differential affinity to lectin Lens culinaris agglutinin (LCA) compared to that from chronic hepatitis/liver cirrhosis. According to their binding capability to LCA, total AFP can be separated into three different glycoforms, AFP-L1, AFP-L2, and AFP-L3. AFP-L1 is the non-LCA-bound fraction, which constitutes the major glycoform of AFP in serum of chronic hepatitis and liver cirrhosis. AFP-L3 is the LCA-bound fraction of AFP. It has been reported that malignant liver cells produce AFP-L3, even when HCC is at its early stages, and especially when the tumor mass is supplied by the hepatic artery. Clinical research has determined that AFP-L3 is a highly specific marker for HCC. The AFP-L3 can be detected in the serum of approximately 35% of the patients with small HCC (<2 cm). The AFP-L3-positive HCC has potential for rapid growth and early metastasis. Compared to imaging techniques, it has been shown to have 9-12 months of lead-time in early HCC recognition. Combined sensitivity of AFP-L3 for HCC is 56%, with a specificity of >95%. METHODS: Automated assay for measuring AFP-L3 has been developed and introduced in clinical use. The new automated method for measurement of ALP-L3 is based on liquid phase binding of the AFP-L3 glycoform with LCA and two specific monoclonal antibodies labeled with peroxidase and polysulfated tyrosine peptide, respectively. CONCLUSION: AFP-L3 is a new generation of tumor marker for HCC and yields useful information on HCC for clinical decision making.

Alpha-amylase assay with use of a benzyl derivative of p-nitrophenyl alpha-maltopentaoside, BG5P.

p-Nitrophenyl O-(6-O-benzyl)-alpha-D-glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl- (1----4)-O-alpha-D-glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1-- --4)-alpha-D-glucopyranoside (BG5P) is hydrolyzed by both human salivary alpha-amylase (HSA) and human pancreatic alpha-amylase (HPA) to O-(6-O-benzyl)-alpha-D-glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl- (1----4)-alpha-D-glucopyranose (BG3) and p-nitrophenyl alpha-maltoside (G2P). Glucoamylase and alpha-glucosidase cannot hydrolyze BG5P because of the modification of the OH group of the 6-position of the non-reducing-end glucose residue with the benzyl group. Taking advantage of these characteristics of the substrate, BG5P, we developed a method to assay the total alpha-amylase activity in human fluids using glucoamylase and alpha-glucosidase as the coupled enzymes. This method is simple and can be used as the standard method for routine clinical assays of alpha-amylase activity.

Renin assay using a fluorogenic substrate and high performance liquid chromatography.

Measurement of renin activity in human fluids using a fluorogenic substrate and high performance liquid chromatography (HPLC) is described. A nine amino acid peptide containing the fluorogenic residue, N-(2-pyridyl) glycine (Pg) is used as a substrate. The peptide sequence is homologous with the cleavage site of human angiotensinogen. This substrate is hydrolyzed by renin to generate fluorogenic and non-fluorogenic products. The amount of fluorogenic product is directly measured by reversed phase HPLC. Optimization of assay conditions and measurement of human serum renin levels are described. Assay results correlated well with those from radioimmunoassay. The method is simple, convenient, highly sensitive and can be used for routine clinical renin assays.

Kinetics of human pancreatic and salivary alpha-amylases with carboxymethylamyloses as substrates.

The enzymatic measurement of alpha-amylase in human serum with chemically modified amylose as substrate was studied. Several substitutions of carboxymethylamylose were prepared from amylose, suitable amounts of monochloroacetic acid, and sodium hydroxide. The relationship between the degree of substitution of the carboxymethylamylose and the kinetic parameters of human pancreatic, salivary and porcine pancreatic alpha-amylases was determined. The action of alpha-amylases on such modified amyloses in the presence of glucoamylase was measured by a specific enzymatic assay having glucose as the product. The kinetic parameters of human pancreatic alpha-amylase were similar to those of human salivary alpha-amylase. It was possible to determine suitable sensitivities for the alpha-amylase assay using this substrate. These results suggested a subsite model.

Comparison of carbohydrate structures of serum alpha-fetoprotein by sequential glycosidase digestion and lectin affinity electrophoresis.

Serum alpha-fetoprotein (AFP) is a glycoprotein of which the sugar chain is considered to show structural changes with malignancies. Microheterogeneity of the serum AFP carbohydrate structure was studied in samples from 35 patients with benign and malignant diseases. Sera were digested directly, extensively, and sequentially with sialidase. beta-galactosidase and beta-N-acetylhexosaminidase. Before and after digestion, sera were examined by means of lectin affinity electrophoresis using eight lectins. Relationships between AFP carbohydrate structures and liver diseases were elucidated by the lectin-reactive profiles and the effect of glycosidase digestion. More than 94% of the AFP carbohydrate structures found in patients with benign and malignant liver diseases were biantennary complex-type oligosaccharides. Changes in the AFP carbohydrate structures at the early stage of hepatocellular carcinoma revealed the addition of alpha 1-->6 fucose to the reducing terminal N-acetylglucosamine and monosialylated AFPs. In both advanced hepatocellular carcinoma and AFP producing extrahepatic malignancies, AFP carbohydrate structures were characterized as the further addition of beta 1-->4 N-acetylglucosamine and heterogeneity in the galactose and N-acetylglucosamine residues. Sequential glycosidase digestion and lectin affinity electrophoresis is useful for analysing the carbohydrate structures of serum glycoprotein.

Establishment of assay kits for the determination of microheterogeneities of alpha-fetoprotein using lectin-affinity electrophoresis.

Diagnostic kits for determination of alpha-fetoprotein (AFP) carbohydrate chain microheterogeneity were developed using lectin affinity electrophoresis with Lens culinaris agglutinin-A (LCA-A) and erythro-agglutinating phytohemagglutinin-E4 (PHA-E4). Separated AFP bands by electrophoresis were detected with high sensitivity by antibody-affinity blotting and immunoenzymatic amplification. Densitometry was used to apportion lectin reactive AFPs. The within-run S.D. for proportions of AFP bands was below 3%. Band intensity was linearly related to AFP concentration between 2 and 200 ng/ml. Profiles of lectin reactive AFPs were compared in serum samples from 55 patients having liver diseases. The average values of lectin reactive AFPs for chronic hepatitis and liver cirrhosis patients were both below 13%, but those of hepatocellular carcinoma patients were above 25%. Correlation of data with disease states suggests that the methods can greatly facilitate the discrimination between benign and malignant liver diseases.

Alpha-fetoprotein microheterogeneity: a potential biochemical marker for Down's syndrome.

Our purpose was to examine the utility of analyzing alpha-fetoprotein (AFP) microheterogeneity assessed by lectin affinity in Down's syndrome (DS) screening. Maternal sera and amniotic fluids were collected from 18 women who were carrying DS fetuses and 70 unaffected pregnancies around 16 weeks of gestation. The percentages of AFP which reacted with Lens culinaris agglutinin (AFP-L2,3) were determined by lectin affinity electrophoresis. AFP-L2,3 levels were significantly increased (P<0.0001) in both maternal serum and amniotic fluid from DS-affected versus unaffected pregnancies. The fractional areas under the receiver operating characteristic curves were 0.835 and 0.700 (P=0.106) for AFP-L3 and AFP MoM (multiples of the median) in maternal serum. No correlation was found between AFP-L3 and AFP MoM in maternal serum (r=0.006). Our data suggest that the measurement of AFP-L3 in maternal serum is a potential biochemical marker for DS.

Clinical evaluation of lentil lectin-reactive alpha-fetoprotein-L3 in histology-proven hepatocellular carcinoma.

INTRODUCTION: Serum alpha-fetoprotein (AFP) is a useful marker of hepatocellular carcinoma (HCC), although the serum AFP concentration is also increased in patients with chronic liver diseases (CLD). The analysis of AFP glycoforms has been known to be of diagnostic value. We applied the lectin-affinity electrophoresis and antibody-affinity blotting techniques to HCC patients in Vietnam in order to better understand the role of lentil lectin-affinity AFP-L3 in the diagnosis and differential diagnosis of HCC, and its relationship with the biological characteristics of HCC. METHODS: Lens culinaris agglutinin-reactive AFP (AFP-L3) was measured in 65 patients with histologically proven HCC and 25 patients with CLD. All patients had serum AFP levels above 54 ng/mL. AFP-L3 levels were determined by lectin affinity electrophoresis coupled with antibody-affinity blotting. The diagnosis of HCC was confirmed histologically by ultrasound-guided biopsy. RESULTS: The mean value of AFP-L3 in the HCC patients was 49.6 +/- 21.6%, which was significantly higher (p<0.001) than that in the 25 CLD patients (10.7 +/- 4.3%). When the cutoff level for AFP-L3 was set at 15% (mean +/- SD), the sensitivity was 96.9%, the specificity 92.0% and the accuracy 95.5% in the 65 HCC patients. There was no clear correlation between serum AFP level and AFP-L3 percentage (r=0.16). There was no correlation between AFP-L3 and the maximum diameter of HCC nodules (r=0.05). However, the mean AFP-L3 value was higher in moderately or poorly differentiated HCC than in well differentiated tumors (p<0.001). CONCLUSIONS: AFP-L3 is potentially a clinically useful marker for the differentiation of increased AFP levels in hepatocellular carcinoma and chronic liver diseases. The AFP-L3 percentage is closely related to HCC differentiation. We consider the analysis of AFP-L3 a useful adjunct in the diagnosis of HCC.

Monitoring of lectin-reactive alpha-fetoproteins in patients with hepatocellular carcinoma treated using transcatheter arterial embolization.

OBJECTIVE: To evaluate the value of lectin-reactive alpha-fetoprotein (LR-AFP) levels for assessing therapeutic effects and for predicting prognosis in patients with hepatocellular carcinoma (HCC) treated using transcatheter arterial embolization (TAE). DESIGN: Twenty-nine patients with HCC were studied. METHODS: LR-AFP levels were measured using lectin-affinity electrophoresis coupled with antibody-affinity blotting. Patients who were initially LR-AFP-positive were divided into those who became negative after TAE and those who remained positive. Patients were also classified into groups showing a reduction in total AFP levels of 75% or more and those showing a reduction of less than 75% and into groups whose tumour size was reduced by 50% or more and those whose tumour size was reduced by less than 50%. RESULTS: Both the length of time between TAE and the recurrence of HCC and the cumulative survival rate differed significantly between the group of patients who became negative after TAE and that which remained positive. However, no significant differences in these parameters were found between the patients in the two classes for total AFP levels or tumour size. CONCLUSIONS: LR-AFP levels appeared to be more useful for predicting clinical results than the serum total AFP value or changes in tumour size.

Synthesis of p-nitrophenyl 6(5)-O-benzyl-alpha-maltopentaoside, a substrate for alpha amylases.

p-Nitrophenyl alpha-maltopentaoside, having a benzyl group on O-6 of the terminal (nonreducing) D-glucosyl group was prepared by use of a reductive ring-opening reaction. Highly regioselective reduction of p-nitrophenyl O-(2,3-di-O-benzoyl-4,6-O-benzylidene-alpha-D-glucopyranosyl)-(1----4)- tris[O-(2,3,6-tri-O-benzoyl-alpha-D-glucopyranosyl)-(1----4)]-2,3,6-tri- O- benzoyl-alpha-D-glucopyranoside by dimethylamine-borane and p-toluenesulfonic acid, followed by debenzoylation, gave p-nitrophenyl O-(6-O-benzyl-alpha-D-glucopyranosyl)-(1----4)-tris[O-alpha-D-glucopyran osyl- (1----4)]-alpha-D-glucopyranoside. An experiment was done on the mode of action of human pancreatic and salivary alpha amylases on this derivative. The compound is suitable as a substrate for the assay of alpha amylase when used with glucoamylase and alpha-D-glucosidase as coupling enzymes.