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C Pascual

Publications and source records attributed to C Pascual.

At least 91 records · Page 5Linked to original sources

[Normal values of the immunoglobulin G subclasses in an adult population. Importance in a study of their deficiency].

BACKGROUND: Quantification of the IgG subclasses (IgGS) requires highly sensitive and specific techniques since their molecular structure is more than 95% homologous. At present, ELISA and RIA are the most appropriate techniques; although the variability of these techniques and the possible ethnic differences in serum levels of IgGS oblige each laboratory to establish its own reference values in a normal population, a condition necessary for defining IgGS deficits. METHODS: In the present study the normal serum values of IgGS in 100 healthy individuals were established. Serum quantification of the IgGS was performed by optimization of the indirect ELISA technique using AcMo and OMS reference standards H00-03 for the 4 subclasses, calibrated vs the OMS WHO 67/97 pattern. RESULTS: Normal values observed for IgG1 were 2.61-10.81 g/l; IgG2, 1.12-4.08 g/l; IgG3, 0.22-2.88 g/l; and IgG4, 0.05-1.56 g/l obtained as of the mean +/- 2 SD for IgG1 and as of the extent of the values of the remaining 3 subclasses by following a non-normal distribution. The sensitivity of the technique was 0.05 g/l with mean intra and inter analysis coefficients of 3.5% and 10.7% respectively. The correlation between total IgG and the sum of the 4 subclasses showed a r = 0.894 (p less than 0.01). CONCLUSIONS: The ELISA technique using AcMo and OMS reference standards is an adequate method for the quantification of the IgG subclasses. However, given the variability of this technique and in order to avoid error, strict working conditions, such as the use of control sera at 2 concentration levels, should be observed for the 4 IgGS in each of the analytic series and each series should also be duplicated.

Adult↗

[Pure red-cell aplasia associated with chronic myeloproliferative syndromes].

Pure red cell aplasia is manifested by unregenerative anemia with intense erythroid hypoplasia in the bone marrow and absolute reticulocytopenia. Its association with chronic myeloproliferative syndrome (CMS) is infrequent. The appearance of both processes may or may not be simultaneous and accidental association cannot be ruled out. Two cases of pure red cell aplasia were studied; one associated to Philadelphia positive chronic chromosome myeloid leukemia and the other associated to atypical CMS. In the first case no response was obtained with prednisone alone or associated to cyclophosphamide. In the second patient treatment with danazol was not efficient, however, corticotherapy produced a positive and maintained response. Treatment of pure red cell aplasia associated to CMS must be the same as that employed when this disease is presented as isolated or associated to other processes.

Aged↗

Effect of antioxidants on chemiluminescence produced by reactive oxygen species.

Luminol chemiluminescence was used to evaluate the scavenging of superoxide, hydroxyl and alkoxy radicals by four antioxidants: dipyridamole, diethyldithiocarbamic acid, (+)catechin, and ascorbic acid. Different concentrations of these compounds were compared with well-known oxygen radical scavengers in their capacity to inhibit the chemiluminescence produced in the reaction between luminol and specific oxygen radicals. Hydroxyl radicals were generated using the Fenton reaction and these produced chemiluminescence which was inhibited by diethyldithiocarbamate. Alkoxy radicals were generated using the reaction of tert-butyl hydroperoxide and ferrous ion and produced chemiluminescence which was inhibited equally by all of the compounds tested. For the determination of superoxide scavengers we describe a new, simple, economic, and rapid chemiluminescence method consisting of the reaction between luminol and horseradish peroxidase (HRP). With this method it was found that 40 nmol/l dipyridamole, 0.18 mumol/l ascorbic acid, 0.23 mumol/l (+)catechin, and 3 mumol/l diethyldithiocarbamic acid are equivalent to 3.9 ng/ml superoxide dismutase (specific scavenger of superoxide) in causing the same degree of chemiluminescence inhibition. These results not only indicated that the antioxidative properties of these compounds showed different degrees of effectiveness against a particular radical but also that they may exert their action against more than one radical.

Antioxidants↗

Hepatoprotective effects of lobenzarit disodium on acetaminophen-induced liver damage in mice.

We have studied the effects of the immunomodulator drug lobenzarit in the model of acute hepatotoxicity induced by a high oral dose (600 mg/kg) of acetaminophen in mice. Lobenzarit at doses of 25, 50 and 100 mg/kg i.p. decreased significantly the activity of alanine aminotransferase in serum, which was increased by acetaminophen alone, and increased the concentration of reduced glutathione in mice liver, which is depleted by acetaminophen. Lobenzarit also reduced liver damage induced by acetaminophen in mice, which was observed by electron microscopy. The hepatoprotective effects of lobenzarit were dose-dependent and they were produced when lobenzarit was administered 30 min before acetaminophen or 2 and 4 h after it. It is concluded that lobenzarit exerts some effects which resemble those of an antidote of acetaminophen such as N-acetylcysteine.

Acetaminophen↗

Fish allergy: evaluation of the importance of cross-reactivity.

Fish constitute one of the most important groups of allergens in the induction of immediate (type I) food hypersensitivity. In our environment, fish allergy is present in 22% of all patients with a diagnosis of food hypersensitivity. We studied the allergenic significance of the fish species considered most representative because of their greater consumption in our environment (flatfishes: Pleuronectiformes such as sole, whiff, and witch; Gadiformes such as hake; and Scombriformes such as albacore) or because of the results of previous studies of Gadiformes such as cod. Through the use of isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis immunoblotting, we have observed that several allergens common to all these species are able to bind specific IgE from the sera of sensitized patients. This allergenic community has been confirmed by radioallergosorbent inhibition. Another group of species-specific allergens focuses in the regions at about pH 5 and with molecular weights less than 14 kilodaltons; these allergens correspond to sarcoplasmic parvoalbumins. From the results observed, which have been confirmed by various procedures and techniques, we conclude that hake is the fish with the capability to induce the strongest IgE response, followed by whiff; the witch seems to be the least allergenic of all flatfishes. Among all species studied, albacore was the least allergenic. These results may be considered when one introduces supplementary feeding with fish in infants, most particularly in infants at high risk for atopy.

Cross Reactions↗

Luminol luminescence induced by 2,2'-Azo-bis(2-amidinopropane) thermolysis.

2,2'-Azo-bis(2-amidinopropane) thermolysis induces luminol luminescence. The luminescence intensity is quenched by SOD, catalase, Trolox and human blood serum. However, the time course of the light intensity profile is different for the different additives. In particular, the quenching efficiency of Trolox and human blood serum decreases with time after addition. Double quenching experiments show that SOD and Trolox are not competitive quenchers, while a simple competition can be established between Trolox and human blood serum in trapping a common intermediate. From the kinetic analysis of the data it is concluded that, at least at low additive concentrations, Trolox scavenges a luminol derived radical. Higher concentrations of Trolox or human blood serum produce induction times that are proportional to the additives concentrations. The possibility of employing luminol luminescence in the evaluation of TRAP levels and the capacity of biological samples to scavenge free radicals is discussed.

Amidines↗

Multicentre evaluation of the Boehringer Mannheim/Hitachi 747 analysis system.

Analytical performance and practicability of the new Boehringer Mannheim/Hitachi 747 analysis system were assessed in a multicentre evaluation involving four laboratories. The analytical performance was evaluated according to a protocol similar to the ECCLS guidelines and comprised 13 analytes including enzymes, substrates and electrolytes. About 65,000 results were obtained within three months. The evaluation was planned and supported by a program system called "Computer Aided Evaluation". Acceptance criteria have been established for judging the results. The median of the within-run coefficients of variation (CVs) in control sera of all methods was below 1%, being far below the acceptance limit of 2%. The median of CVs of between-days imprecision was below 2% (acceptance criterion 3%). The high degree of precision prompted us to set up a biometrical model suitable for the differentiation between deviant points, outliers and measurements that can still be explained by the system performance. No relevant drift effects were observed during eight hours. The methods were linear over a wide range, avoiding rerun analysis in most cases. No sample-related carry-over was found. Reagent-dependent carry-over outside the acceptance limits was measured from uric acid to phosphorus to a slight extent, and from triacylglycerols to lipase, as well as from total protein to bilirubin to a perceptible degree. It can be avoided by separating these reagent combinations in the channel arrangement. Taking a systematic deviation of more than 10% as unacceptable, four of the 13 analytes suffered from interference by haemoglobin, one by bilirubin and one by turbidity. The Boehringer Mannheim/Hitachi 747 analysis system is capable of determining serum indices which in combination with the interferogram allow an assessment of the interference. With the exception of chloride the recovery of the assigned values for all control sera showed values between 95 and 105%. Out of 40 method comparison studies for enzymes and substrates, 31 yielded regression equations with less than 5% proportional errors and less than 5% constant errors. Deviations exceeding these acceptance criteria can be explained by differences in the reagent formulation, in the method employed or in calibration. The agreement of the ISE method comparisons was within a +/- 5% deviation over a wide analytical range. Practicability of the Boehringer Mannheim/Hitachi 747 analysis system was assessed with the help of a questionnaire, in which properties of the instrument were quantified, thus permitting a relatively objective rating. The 190 questions were placed in 14 groups, each dealing with an attribute of the instrument.(ABSTRACT TRUNCATED AT 400 WORDS)

Autoanalysis↗

Drugs effects on superoxide generation and chemiluminescence response of human leukocytes.

Luminol-enhanced chemiluminescence was used to determine the effects of diethyldithiocarbamate, dipyridamole, catechin and verapamil on the generation of reactive oxygen species in human leukocytes, and on superoxide generated by chemiluminescence of the hypoxanthine xanthine-oxidase reaction. These agents reduced the luminol enhanced chemiluminescence response of activated leukocytes, most probably by inhibiting the superoxide generation reaction. On the other hand, citrate and diethylcarbamazine, produced a slight increase of the luminol enhanced chemiluminescence of leukocytes.

Catechin↗

Diagnostic value of ascites gamma interferon levels in tuberculous peritonitis. Comparison with adenosine deaminase activity.

The value of ascites gamma interferon concentration and ascites adenosine deaminase activity in distinguishing tuberculosis from other causes of ascites was examined in a prospective study of 86 patients with ascites, including 16 with tuberculous peritonitis. Gamma interferon concentration was higher in tuberculous peritonitis than in the other causes of ascites (p less than 0.0001), and a cut-off between 3 and 9 u/ml reached a sensitivity and a specificity of 100%. The mean (+/- SD) gamma interferon level in tuberculous ascites was 39.3 +/- 18.3 u/ml in patients seronegative for HIV and 14.2 +/- 4.7 u/ml in patients with AIDS (p = 0.01). Adenosine deaminase activity in tuberculous ascites was also higher than in the other causes of ascites (p less than 0.0001), and a cut-off of 40 u/l reached a sensitivity of 100% and a specificity of 97%. The two false positives for adenosine deaminase test were true negatives for the gamma interferon test. There was no significant correlation between gamma interferon concentration and adenosine deaminase activity either in tuberculous ascitis or in any other group. This study suggests that ascites gamma interferon determination may be very useful in the screening of tuberculous peritonitis, but its cost makes it advisable to use adenosine deaminase activity as a routine test, at least in areas where tuberculosis is endemic.

Adenosine Deaminase↗

New methods for the assay of 5-isosorbide mononitrate and its validation.

Differential scanning calorimetry (DSC) is a method which has been applied to obtain thermal information about both raw material and the determination of the content of 5-ISMN in dry mixtures with lactose. The main advantage this offers, compared to other methods, is that it is not necessary to use a standard, it only being necessary to know the data of its fusion heat. HPLC and TLC-densitometry are considered for the determination of 5-ISMN: lactose and pharmaceutical dosage forms. Linearity test, repeatability and accuracy were satisfactory in both methods. Recovery data in pharmaceutical formulations (expressed as the percentage of the label claim) from HPLC and TLC did not give any significant difference (P = 95%). The results show that the chromatographic methods are simple, fast and reliable procedures for the determination of 5-ISMN.

Calorimetry, Differential Scanning↗

Antiphospholipid antibodies in migraine.

We studied the presence of serum antiphospholipid antibodies (APA) in 35 patients with migraine and 75 controls. None of the controls showed APA, while we found these antibodies in five patients out of the 35 studied (p = 0.003). The clinical features of migraineurs with APA were similar to those of patients without them. After a follow-up of one to two years, no patient suffered any neurological complications or developed any clinical features that would suggest the presence of autoimmune disease. Our results suggest that APA are not prominent in the pathogenesis of migraine attacks, or significant in the course of otherwise healthy migraine patients.

Adult↗

[The antioxidative activity of drugs in the liver microsomal system of rats].

The antioxidative properties of drugs--diethylcarbamazine citrate--DECC, dipyridamole-DP, levamisole and labinzarit--have been investigated in various microsomal lipid peroxidation (LPO) models: NADPH-, ascorbate- and CCl4-dependent. The most strong antioxidant of direct action turned out to be DP, DECC exhibited the antioxidative properties as a result of metabolic activity in monooxygenases system of rat liver microsomes. Levamisole and labinzarit turned out to be weak antioxidants. The control of microsomal membrane stability against Fe(2+)-ADP, NADPH-induced LPO, after being isolated from rat liver after the action of CCl4 without and with DECC, showed that DECC protected microsomal membranes from CCl4 in vivo and they remained stable against LPO in vitro.

Animals↗

[Gamma interferon and adenosine deaminase in pleuritis].

The concentration of gamma interferon (IFN gamma) and adenosine deaminase (ADA) activity were measured in the pleural fluid of 162 patients to compare their diagnostic significance and to establish a possible correlation between both tests. The IFN gamma levels in tuberculous pleural effusions were quite variable, with a mean of 93 U/ml and a median of 48 U/ml. They were higher than 2 U/ml in all cases, whereas no case of nontuberculous effusion showed higher values. ADA activity was higher than 43 U/l in all tuberculous effusions, with a mean value of 80 U/l, higher than in any other group except lymphoma. In three pleural effusions associated with lymphoma, one with mesothelioma, one with adenocarcinoma and four with empyema, ADA activity was higher than 43 U/l. In these patients, IFN gamma levels were low. There was no correlation in the whole series or in any group between IFN and ADA. Both parameters can be very useful for the diagnosis of tuberculous pleuritis. The measurement of IFN gamma is more specific, although the experience with this test is more limited than with ADA. It has the additional shortcoming of a high cost and it requires facilities for radionuclide use. Therefore, we think that ADA measurement should be considered as a routine test while IFN gamma measurement should be reserved for reference institutions.

Adenosine Deaminase↗