Hepatitis delta genotypes in chronic delta infection in the northeast of Spain (Catalonia)

BACKGROUND/AIMS

Based on genetic analysis of variants obtained around the world, three genotypes of the hepatitis delta virus have been defined. Hepatitis delta virus variants have been associated with different disease patterns and geographic distributions. To determine the prevalence of hepatitis delta virus genotypes in the northeast of Spain (Catalonia) and the correlation with transmission routes and clinical disease, we studied the nucleotide divergence of the consensus sequence of HDV RNA obtained from 33 patients with chronic delta hepatitis (24 were intravenous drug users and nine had no risk factors), and four patients with acute self-limited delta infection.

METHODS

Serum HDV RNA was amplified by the polymerase chain reaction technique and a fragment of 350 nucleotides (nt 910 to 1259) was directly sequenced.

RESULTS

Genetic analysis of the nucleotide consensus sequence obtained showed a high degree of conservation among sequences (93% of mean). Comparison of these sequences with those derived from different geographic areas and pertaining to genotypes I, II and III, showed a mean sequence identity of 92% with genotype I, 73% with genotype II and 61% with genotype III. At the amino acid level (aa 115 to 214), the mean identity was 87% with genotype I, 63% with genotype II and 56% with genotype III. Conserved regions included the RNA editing domain, the carboxyl terminal 19 amino acids of the hepatitis delta antigen and the polyadenylation signal of the viral mRNA.

CONCLUSIONS

Hepatitis delta virus isolates in the northeast of Spain are exclusively genotype I, independently of the transmission route and the type of infection. No hepatitis delta virus subgenotypes were found, suggesting that the origin of hepatitis delta virus infection in our geographical area is homogeneous.

Interleukin-8 and markers of neutrophil degranulation in pleural effusions

In order to know the degree of interleukin-8 (IL-8) production in the pleural space and its relationship to neutrophil activation, IL-8, neutrophil elastase (NE), and myeloperoxidase (MPO) were assessed in blood and pleural fluid (PF) of 219 patients with pleural effusions. Correlations between blood and PF IL-8, NE, and MPO were either absent or weak, except for IL-8 in transudates (r = 0.6745, p < 0.001). PF IL-8, NE, and MPO concentrations in cases of empyema were higher than in cases of effusion of other causes (p < 0.001). No significant differences in inflammatory markers were observed between parapneumonic and tuberculous fluids. IL-8, NE, and MPO levels in malignant, nonspecific, and transudative effusions were lower than in those due to infection, the lowest levels corresponding to transudates. No significant correlation was observed between PF IL-8 and neutrophil count in any group; in contrast, IL-8 was associated with NE and MPO in empyema (r = 0.7545, and r = 0.7283; p < 0.001), tuberculosis (r = 0.4016, p = 0.008 and r = 0.6545, p < 0.001), and nonspecific effusions (r = 0.3748, p = 0.007 and r = 0.3085, p = 0.028). Our results indicate that local production of markers of the nonspecific inflammatory response is high in both chronic and acute pleural infection, and suggest a role for IL-8 in the release of NE and MPO.

Total plasma antioxidant capacity is not always decreased in sepsis

OBJECTIVE

To compare total plasma antioxidant capacity and selected individual antioxidants in patients with varying degrees of severity of sepsis.

DESIGN

A prospective, observational, consecutive case study.

SETTING

A 16-bed intensive care unit (ICU) in a university teaching hospital.

INTERVENTIONS

None.

PATIENTS

Forty-six healthy controls, ten ICU patients, nine patients with systemic inflammatory response syndrome (SIRS), 11 septic patients, and 14 septic shock patients. Plasma was obtained in healthy patients scheduled for minor surgery immediately before anesthesia and in ICU patients within 24 hrs of admittance to the unit or diagnosis of SIRS, sepsis, or septic shock.

MEASUREMENTS AND MAIN RESULTS

Using the total peroxyl radical trapping method, we found plasma antioxidant capacity to be lower in septic patients but higher in septic shock patients, as compared with controls. Bilirubin was the greatest contributor to the increase with shock, followed by uric acid. Neopterin also correlated with the peroxyl radical trapping antioxidant parameter values.

CONCLUSION

Although total plasma antioxidant capacity is decreased from normal levels in septic patients, an increase in some oxidants contributes to an increased total antioxidant capacity in septic shock patients.

Corynebacterium phocae sp. nov., isolated from the common seal (Phoca vitulina)

Phenotypic and phylogenetic studies were performed on four strains of a Gram-positive non-acid-fast coryneform-like organism isolated from the nasal cavities of common seals (Phoca vitulina). Chemotaxonomic investigations revealed the presence of corynomycolic acids in the unidentified isolates, which is consistent with corynebacteria. 16S rRNA gene sequence analysis demonstrated that the strains from seals represent a hitherto unknown subline within the genus Corynebacterium sensu stricto. Based on the results of the phylogenetic analysis and phenotypical criteria, it is proposed that the bacterium should be classified as a new species, Corynebacterium phocae. The type strain of Corynebacterium phocae is CCUG 38205T.

Streptococcus parasanguinis: new pathogen associated with asymptomatic mastitis in sheep

We describe two unusual cases in sheep of subclinical mastitis caused by Streptococcus parasanguinis. This bacterium has been associated with the development of experimental endocarditis; its presence at relatively high concentrations in apparently healthy sheep milk may pose a health risk in persons with predisposing heart lesions.

Vancomycin monitoring: one or two serum levels?

Based on the principle that vancomycin therapy requires sustained therapeutic concentrations while avoiding high peaks, some authors reported that optimal vancomycin levels could be ensured by measuring trough levels alone (Cmin). The aim of this work was to assess the performance of a one-compartment Bayesian forecasting method for estimating vancomycin 2 hours after infusion (C2h) and mean vancomycin concentration in steady state (Cavgss) on the basis of a single trough sample (Cmin), in different conditions (steady state, patient renal function, and age), and according to clinical significance. Vancomycin serum concentrations (n = 108) were analyzed by fluorescence polarization immunoassay, from 79 adult patients. The predictive performance of the Bayesian method was determined by calculating the mean prediction error (ME), the mean absolute error (MAE) and the root squared prediction error (RMSE). A linear regression analysis was carried out between estimated and observed concentrations. The predicted C2h were not significantly different from the observed, and the least biased (ME = -1.08) and most precise (MAE = 3.81) predictions were from patients with normal renal function and steady state conditions. In this population, the concordance in dosage recommendations with the data pair results was 75% of patients. The best correlation between observed and predicted concentrations was found for Cavgss (r = 0.94; p < 0.00005). Predictions of the Cavgss were more precise (ME = -0.54) and accurate (MAE = 1.74) than the C2h predictions. Vancomycin can be monitored by determining one level in steady state for most patients with normal renal function.

[Molecular characterization of two variants of alpha-1-antitrypsin deficiency: PI Mpalermo and PI Plovel]

BACKGROUND

Alpha 1 antitrypsin (AAT) is a highly polymorphic protein, having more than 75 different variants. In this work two rare AAT deficient variants were characterized by DNA study.

PATIENTS AND METHODS

Members of three generations of two separate families were studied. In family 1, the index case was affected with pulmonary emphysema and presented AAT deficiency (23 mg/dl). In family 2, the index case had a normal pulmonary function, an AAT serum level of 72 mg/dl and a phenotype heterozygous for an AAT variant migrating in the P variant region. The AAT variants were characterized by polymerase chain reaction amplification of the coding exons and direct sequencing of the amplification products.

RESULTS

Direct DNA sequencing from a member of family 1 demonstrates that in the exon II of the normal M1 (Val213) allele there was a 3-bp deletion (TTC), corresponding to Phe51 or Phe52. This mutation is characteristic of the Pl Mpalermo variant. In our study, Pl Mpalermo was detected in six members of three generations of this same family. Sequencing of exon III in a member of family 2, identified in the common M1 (Val213) allele a single base substitution of GAT-GTT, with the resulting amino acid change Asp256 for Val256. This mutation characterizes the Pl Plovel allele. The Pl Plovel was also detected in nine members of five others independent families. All of them have AAT serum levels between 80 and 102 mg/dl. None of the studied subjects had clinical evidence of lung disease.

CONCLUSIONS

The results of our study show the presence of the two AAT deficient variants in Spain and suggest that the Pl Plovel variant might be more common than expected.

IgE crossreactivity between mugwort pollen (Artemisia vulgaris) and hazelnut (Abellana nux) in sera from patients with sensitivity to both extracts

BACKGROUND

An association between sensitization to Compositae pollens and hypersensitivity to hazelnut has been previously described. There is no previous in vitro study about crossreactivity between mugwort pollen and hazelnut.

OBJECTIVES

To study mugwort pollen and hazelnut allergens and to assess if there is IgE crossreactivity between mugwort pollen and hazelnut.

METHODS

A serum pool formed by 28 individual sera with specific IgE to mugwort pollen and hazelnut was used to investigate IgE crossreactivity. RAST-inhibition, SDS-PAGE/IEF immunoblotting inhibition assays were performed by preincubation of the sera with mugwort pollen and hazelnut.

RESULTS

RAST to hazelnut was inhibited up to 63% by mugwort pollen, but the mugwort pollen RAST was only inhibited up to 36% by hazelnut. In SDS-PAGE immunoblotting mugwort pollen showed nine allergens ranging from <16 to 65 kDa and hazelnut had four main allergens: 42 kDa, 17 kDa and <16 kDa (two bands). In the SDS-PAGE immunoblotting inhibition hazelnut partially inhibited all the mugwort pollen bands, except that with 19kDa, whereas mugwort pollen produced a nearly total inhibition of all the hazelnut allergens. In isoelectrofocusing immunoblotting mugwort pollen had two groups of allergens: pI 7.5-8.5 and pI 3.5-5.2 and hazelnut one group of allergens: pI 5.2-5.8. In the isoelectrofocusing immunoblotting inhibition hazelnut produced a partial inhibition of all the bands of mugwort pollen and mugwort pollen partially inhibited all the allergenic bands of hazelnut.

CONCLUSIONS

The RAST and SDS-PAGE/IEF immunoblotting inhibition results provide evidence of IgE cross reactivity between mugwort pollen and hazelnut allergens. The inhibition of hazelnut by mugwort pollen is higher than the inhibition of mugwort pollen by hazelnut in both RAST inhibition and SDS-PAGE immunoblotting inhibition. These results suggest that mugwort pollen allergens would behave as primary immunogens in the association between sensitivity to mugwort pollen and hazelnut.

Actinomyces europaeus sp. nov., isolated from human clinical specimens

Ten strains of a hitherto undescribed catalase-negative, facultatively anaerobic, coryneform bacterium were isolated or collected by workers at three European clinical bacteriology laboratories or reference centers. These strains were isolated from humans, and most came from abscess material. Biochemical and chemotaxonomic characterization revealed that the strains belonged to the genus Actinomyces. The phenotypic features of the 10 strains were incompatible with the descriptions of the previously established Actinomyces species. A comparative 16S rRNA gene sequence analysis demonstrated that the previously undescribed strains constitute a new line in the genus Actinomyces. The name Actinomyces europaeus sp. nov. is proposed for these clinical isolates. The type strain is CCUG 32789A.

A controlled study of leukocyte activation in septic patients

OBJECTIVE

Qualitative and quantitative evaluation of leukocyte activation in septic patients in comparison to two control groups.

DESIGN

A prospective clinical study in which the leukocyte oxidative output of whole blood was measured in three groups of patients. Two chemiluminescence markers (luminol or lucigenin), indicative of either total oxidant output or superoxide production, and three stimuli (opsonized zymosan, formyl-methionyl-leucyl-phenylalanine (fMLP), phorbol myristate acetate) (PMA), representing different pathways of leukocyte activation, were used. Tumor necrosis factor, interleukin-6 and C-reactive protein (TNF, IL-6, and CRP) were determined to evaluate the severity of the inflammatory process.

SETTING

Intensive care and surgical units of a university hospital.

PATIENTS

Seventy-four healthy patients, ten ICU patients without signs of sepsis or systemic inflammatory response syndrome and 19 septic patients were studied.

MEASUREMENT AND MAIN RESULTS

With all three stimuli, whole blood total oxidative output and superoxide production were generally increased in septic patients. This was most likely due to the increased leukocyte numbers in these patients. When the chemiluminescence values were normalized per phagocyte (granulocytes and monocytes), the total oxidative output of septic phagocytes decreased with opsonin and fMLP but increased with PMA, while superoxide output decreased regardless of the stimuli used. TNF, IL-6 and CRP, although increased in septic patients as compared to ICU controls, correlated weakly with oxidant output.

CONCLUSIONS

The oxidative output of whole blood was increased in septic patients compared to controls because of elevated leukocyte numbers. However, oxidant output normalized for phagocyte numbers generally decreases during sepsis for most stimuli. Cytokines and CRP do not appear to be associated with the extent of oxidant output during sepsis.

Determination of D-lactate by enzymatic methods in biological fluids: study of interferences

Analysis of nondeproteinized samples with an enzymatic method to determine D-lactate indicated interferences. The presence of L-lactate dehydrogenase (LD) and L-lactate in the sample led to underestimation of D-lactate content when a sample blank was processed and overestimation when it was omitted. We proved that this interference is not due to lack of D-LD stereospecificity. Moreover, assessment of D-LD and L-LD KM for NAD+ allowed us to rule out the different affinities for this coenzyme as a cause of the interference. Our results underline the importance of deproteinizing samples for D-lactate analysis when enzymatic methods are used. The ultrafiltration procedure we propose is convenient and shows acceptable mean recovery (108%) and good imprecision (within-run CV = 4.2% and 3.0% for D-lactate at 31 and 107 mumol/L, respectively; between-run CVs were 7.3% at 49 mumol/L D-lactate and 3.1% at 115 mumol/L D-lactate).

Characterization of specific immunoglobulin G (IgG) and its subclasses (IgG1 and IgG2) against the 23-valent pneumococcal vaccine in a healthy adult population: proposal for response criteria

The aim of the study was to standardize an enzyme-linked immunosorbent assay (ELISA) method for the quantification of immunoglobulin G (IgG) and its subclasses (IgG1 and IgG2) against the 23-valent pneumococcal vaccine and to establish the criteria for a normal response to the vaccine. Forty healthy individuals (20 women and 20 men; mean age, 29 years) were studied. All were vaccinated with the 23-valent pneumococcal vaccine; blood samples were drawn just prior to and 3 weeks after immunization. Quantification of specific IgG and its subclasses was performed by an ELISA with the vaccine as the antigen. The linearity of the ELISA method was demonstrated by the similar slopes of the linear regression lines generated from the titration of sera with different antibody concentrations. The specificity of the antibodies against the vaccine was demonstrated by (i) an absorption test with pneumococcal vaccine, (ii) a cross-reactivity experiment with Haemophilus influenzae type b polysaccharide, and (iii) affinity chromatography with protein A-Sepharose. Response to the vaccine was defined by using the lower level of the 90% probability interval (one-tailed) for postimmunization-specific IgG, IgG1, and IgG2. By using this cutoff, responders were considered to be those with an absolute increase in antibody titers higher than 395 arbitrary units/ml for IgG, 0.350 A450 units for IgG1, and 0.314 A450 units for IgG2. Overall, 20 (50%) subjects had IgG, IgG1, and IgG2 responses, 9 (22.5%) had IgG and IgG2 responses, 4 (10%) had IgG1 responses, 3 (7.5%) had IgG and IgG1 responses, and 4 (10%) were nonresponders. Ninety percent of our population responded to the 23-valent pneumococcal vaccine. Up to 10% of healthy individuals may respond to an IgG subclass without significant increases in total IgG titers. The ELISA method that is described may be useful for evaluating the specific antibody response against polysaccharides.

Oxidative tissue response promoted by 5-aminolevulinic acid promptly induces the increase of plasma antioxidant capacity

The heme precursor 5-aminolevulinic acid (ALA), acting as a prooxidant, has been proposed to underlie the clinical manifestations of various porphyric disorders. Accordingly, ALA-generated oxyradicals where shown to cause oxidative lesions in biomolecules and isolated cell organelles and to release iron from ferritin. In rats, administered ALA triggered oxidative stress in liver, brain and red muscles. We now study the correlation between the plasma antioxidant capacity and tissue oxidative damage, after acute (one and two doses) and prolonged (eight doses) ALA treatment of rats (one dose of ALA = 40 mg/kg body weight). The in situ spontaneous chemiluminescence intensity increased 5-fold in brain, 50% in liver and 4-fold in soleus muscle upon two dose-treatment, indicating tissue response to oxidative injury by ALA. Chemiluminescence reached the highest intensity after one or two doses of ALA and decreased after eight doses in all tissues. The plasma trapping capacity, evaluated by the luminol/2-amidinopropane system, gave a parallel response: maximum values after two doses and decreased values after prolonged treatment. After eight doses, the ALA concentration was found to be 3-fold above the normal value in plasma, 48% higher in liver and 38% higher in total brain. These data indicate that the plasma antioxidant system responds to ALA treatment and is correlated with tissue chemiluminescence. In vitro studies showed that ALA does not interfere with the antioxidant plasma capacity, neither promoting oxidation of plasma elements nor binding to plasma proteins.

Influence of biochemical parameters of liver function on vancomycin pharmacokinetics

The influence of biochemical parameters of hepatic function on vancomycin pharmacokinetics was retrospectively evaluated in 76 adult patients (age 18 to 81 years), from biochemistry data gathered during routine therapeutic drug monitoring. All subjects had normal serum creatinine levels. Vancomycin concentrations were determined by fluorescence polarization immunoassay in 101 paired serum samples. All data for vancomycin concentration versus time were fitted to a one-compartment model using the bayesian approach. Bilirubin, transaminases (n = 101), gamma-glutamyl transferase (n = 97), alkaline phosphatase (n = 95), albumin (n = 92) and lactate dehydrogenase (n = 42) were determined. No strong correlation was seen between any of the pharmacokinetic and biochemistry parameters studied. In patients with hyperbilirubinaemia, the mean Vss and t1/2 were increased (Vss: 0.75 +/- 0.31 versus 0.92 +/- 0.42 1.kg-1, p = 0.020; t1/2 5.93 +/- 3.30 versus 7.48 +/- 4.44 hr, p = 0.049). When liver function was evaluated according to hepatic profile (normal, mildly altered and severely altered), no significant differences were observed in vancomycin pharmacokinetics among the groups. In conclusion, vancomycin pharmacokinetics are only weakly influenced by the biochemistry parameters of liver function.

Sanguibacter inulinus sp. nov

Six strains of coryneform bacteria were isolated from blood samples obtained from healthy cows. Phenotypic and molecular genetic studies showed that these isolates represent a new species of the genus Sanguibacter, for which the name Sanguibacter inulinus is proposed. The type strain of S. inulinus is strain ST-50 (= NCFB 3024).

The value of quantitative detection of HBV-DNA amplified by PCR in the study of hepatitis B infection

BACKGROUND/AIMS

This study aimed to evaluate the usefulness of quantifying HBV-DNA amplified by polymerase chain reaction in chronic hepatitis B infection.

METHODS

Serum samples were obtained from 32 asymptomatic HBV carriers and 99 chronic hepatitis B patients (62 positive for anti-HBe and 37 positive for HBeAg). In addition, serial serum samples were analyzed from 15 HBeAg positive patients undergoing antiviral therapy and 17 anti-HBe positive patients with precore mutation. HBV-DNA quantification was carried out using an enzyme immunoassay with an HBV-DNA plasma standard.

RESULTS

The digoxigenin-incorporated polymerase chain reaction method detected HBV-DNA in 34.3% of the asymptomatic HBV carriers with a median HBV-DNA concentration of about 0.18 x 10(5) mol/ml (range 0.08-0.4), in 87% of the anti-HBe positive chronic hepatitis cases with a range of 0.2 to > 2 x 10(5) mol/ml and in 100% of the HBeAg positive patients, with a value in all cases over 2 x 10(5) mol/ml. We observed that after treatment, HBV-DNA tested negative in only two of the eight HBeAg positive chronic hepatitis patients who seroconverted to anti-HBe, and was positive in the seven remaining, with a median HBV-DNA value of about 0.2 x 10(5) mol/ml (0.09-0.4). In the precore mutants HBV-DNA values ranged from 0.2 to > 2 x 10(5) mol/ml.

CONCLUSIONS

Polymerase chain reaction HBV-DNA quantification is a sensitive method for managing chronic hepatitis B patients, especially those with low viremia, and may be a valuable tool for evaluating the efficacy of antiviral therapy.

Improvement of emergency and routine turnaround time by data processing and instrumentation changes

A retrospective study of stat and routine laboratory analysis turnaround time was performed in a 1000-bed public hospital before and after the implementation of instrument and computer changes. Significant decreases in turnaround time were found for enzyme tests in the stat laboratory and for all analytes studied in the routine laboratory. The decrease in TAT was evaluated using a physician satisfaction scale, elaborated in conjunction with specialists from several fields, that disclosed an increase in perceptive quality. Results from other authors and recommendations by the College of American Pathologists for turnaround time are discussed.

Changes in vancomycin pharmacokinetics during treatment

Using data gathered in routine monitoring, the pharmacokinetics of vancomycin during the first 10 days of treatment were compared with the pharmacokinetics after 10 days of treatment in 46 adult patients with normal renal function, ages 17-85 years old (mean +/- SD: 50.8 +/- 17.5). The mean time from initiation of treatment to the first sample determination was 5.5 days, and the mean time to the second determination was 13.4 days. Statistical differences between the two periods were observed for all pharmacokinetic parameters, except for the steady-state distribution volume. After 10 days of treatment, the mean +/- SD of the vancomycin clearance and elimination rate constant decreased from 1.31 +/- 0.82 to 1.13 +/- 0.72 ml/kg/min (p = 0.0044) and from 0.13 +/- 0.08 to 0.10 +/- 0.06 h-1 (p = 0.091), respectively. The half-life (t1/2) increased from 8.01 +/- 6.82 to 10.02 +/- 8.00 h (p = 0.012). The median percentage of the increment of t1/2 was 9.4%. The increase in t1/2 was > 50% in 12 patients and > 100% in nine cases. No association was found between the increment of t1/2 and the cumulative vancomycin dose. Frequent monitoring of serum vancomycin seems indicated, given the risk of decreased elimination during prolonged treatment.

Allergic reactions following skin contact with fish

We evaluated the clinical characteristics found in 29 children who showed allergic symptoms after direct and/or indirect contact with fish, from 197 children diagnosed with IgE-mediated fish hypersensitivity. Allergic reactions to fish through ingestion began in most patients (79%) within the first 24 months of life. All the patients showed cutaneous symptoms, either alone or associated with other clinical manifestations. Whiff and hake were the species more frequently implicated in eliciting clinical manifestations upon ingestion. After diagnosis, all patients were placed on a strict fish avoidance diet. During this period of avoidance, 29 patients reported allergic reactions (mean age 5 years, 6 months; SD 4 years, 2 months) after incidental skin contact with fish. Clinical manifestations after touching fish were only cutaneous in 28 of the 29 studied patients. One showed local urticaria with wheezing. The majority reported two or more episodes. Incidental skin contact with fish could play an important role in accidental encounters with fish particles in children on a fish avoidance diet for fish IgE-mediated hypersensitivity. Such exposures could result in immunologic immediate contact reactions and in some cases could lead to systemic reactions (contact urticaria syndrome).

Cupressaceae pollinosis in the Madrid area

BACKGROUND

There is no previous report of Cupressaceae pollinosis in the Madrid area.

OBJECTIVE

To ascertain the presence of Cupressaceae pollinosis in the Madrid area.

METHODS

Thirty-six patients were studied who had winter pollinosis symptoms and a positive skin test to C. arizonica. They were skin tested with C. sempervirens (Abelló, Madrid), C. arizonica (in-house extract) and other common inhalant allergens (Abelló). Total IgE was measured and specific IgE to C. arizonica, C. sempervirens and J. sabinoides was determined.

RESULTS

Six of the patients were only sensitized to Cupressaceae pollens, whereas 30 patients had also sensitivity to other pollens (oleaceae 28, plantain 27, grasses 25, chenopodium 25, compositae 23, Parietaria 9) and 18 patients were also sensitized to other inhalant allergens (animals 17, mites 4, moulds 2).

CONCLUSION

These results confirm the existence of allergy to Cupressaceae pollens in Madrid (Spain).

The reaction between ABTS radical cation and antioxidants and its use to evaluate the antioxidant status of serum samples

The 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical cation can be generated by incubation of ABTS and 2,2'-azo-bis(2- amidinopropane) at 45 degrees C. The ABTS radical cation is stable for several minutes at room temperature and reacts quantitatively and instantaneously with several antioxidants, such as Trolox, ascorbic acid, uric acid, cysteine, glutathione and bilirubin. In contrast, the ABTS radical cation reacts slowly with albumin. When serum is added to a solution of the ABTS radical cation, the bleaching of the radical follows biphasic kinetics, with a fast decay followed by a slow decay that takes place within several minutes. The fast decay is primarily due to uric acid, while the slow decay is related to the protein content of the sample. We propose that this procedure can provide an independent and simultaneous evaluation of the low molecular weight and protein antioxidants present in biological samples such as serum.