Biomedical subjects

C Juarez

Publications and source records attributed to C Juarez.

At least 37 records · Page 2Linked to original sources

PubMed1994

Comparison of Vespula germanica venoms obtained from different sources.

This study was carried out to compare the allergenic potency of Vespula germanica (VG) venoms extracted by different methods and commercially available venoms from Vespula species currently used for in vivo and in vitro studies including immunotherapy. Pure VG venom was used as the reference material. Protein content and enzymatic and allergenic properties of all venoms studied were determined by dye stain reagent, hyaluronidase and phospholipase A1B enzyme activities, and radioallergosorbent test inhibition studies, respectively. Radioallergosorbent test discs sensitized with commercial and pure VG venom were compared using specific IgE antibodies from subjects allergic to VG venom. The data obtained indicate that there were important differences in the allergenic potency between the Vespula species venoms employed for in vivo and/or in vitro assays, VG venom obtained by sac dissection, and pure VG venom. These results indicate that venoms from Vespula species used for in vitro and in vivo tests have a lower concentration of allergens and contain nonvenom proteins. These data should be taken into account when these vespid venoms are used for diagnostic purposes and also when evaluating immunotherapy studies.

Allergens↗

PubMed1992

Determination of IgE antibodies to the benzyl penicilloyl determinant. A comparison between poly-L-lysine and human serum albumin as carriers.

The influence of two different carriers, poly-L-lysine (PLL) and human serum albumin (HSA) in the binding of specific IgE antibodies to the benzyl penicilloyl hapten (BPO) was determined in a solid-phase assay. Serum samples from patients with a history of immediate reaction to penicillin and which had shown the presence of IgE antibodies to BPO were used. Benzyl penicilloyl derivatized cellulose discs were prepared using PLL of different molecular weight and HSA as carriers. These were treated with different molar ratios of benzyl penicillin. These reagents were compared for uptake of BPO-specific IgE using a pool of sera in a radioallergosorbent test (RAST) type assay. Two PLL systems and two HSA systems were finally compared using 26 individual sera. RAST values were compared by Kruskal-Wallis and Wilcoxon tests. The relationships between the four different assays were evaluated by determining Pearson correlation coefficients and the concordance by determining intraclass correlation coefficients (ICC). Analysis of means by the Wilcoxon test revealed significant differences (P less than 0.01) only when the different carrier assays were compared. The correlation coefficients between all the assays were significant (P less than 0.0001), but the ICC was low when the different carrier assays were compared. These results indicate that the nature of the carriers studied (PLL and HSA) influences the capacity for binding IgE antibodies in the RAST procedure. The differences observed indicate that one conjugate cannot be substituted for the other in the determination of IgE antibodies to BPO and that BPO-PLL is preferable.

Antibodies↗

PubMed1992

Specific IgE antibodies to vespids in the course of immunotherapy with Vespula germanica administered to patients sensitized to Polistes dominulus.

Sera from a group of 12 patients with anaphylactic reactions to vespids were studied. Field observations and RAST values suggested that the offending insect was Polistes dominulus (PD). Specific IgE antibodies to PD appeared in all cases and to Vespula germanica (VG) in nine. Absorption studies in these basal sera showed that IgE antibodies to VG were due to cross-reactivity with PD. The RAST value to both venoms was higher after immunotherapy (IT) in six cases. IgE antibodies increased to determinants common to both vespids, and in 41% of the cases to specific epitopes of VG venom allergens not initially detected in the basal sera. In one case antibodies increased only to VG without a corresponding rise to PD. These results indicate that if the correct venom to which the individuals are sensitized is not administered IgE antibodies may appear which were not initially detected in the patients' sera. The levels of these antibodies declined during the course of IT.

Adult↗

PubMed1991

Effect of intraventricular injection of an anti-Purkinje cell antibody (anti-Yo) in a guinea pig model.

Female guinea pigs had intraventricular injections of either IgG from a patient with paraneoplastic cerebellar degeneration (PCD) and anti-Purkinje cell antibodies (anti-Yo IgG) or control IgG. In animals that received a single injection of control or anti-Yo IgG and were killed at different time intervals, IgG immunoreactivity was present in the cytoplasm of Purkinje cells at 2 h and persisted at 24 h. In guinea pigs injected for 15 days with control or anti-Yo IgG and sacrificed 24 h after the last injection, IgG was detected into the Purkinje cells in both groups, whereas animals killed 7 and 30 days after the last injection had no staining for IgG in the Purkinje cells. Clinical or pathologic evidence of cerebellar involvement was not seen in any of the animals. This study suggests that anti-Yo antibody alone may not be the cause of the Purkinje cell loss in PCD.

Animals↗

PubMed1991

Determination of IgE antibodies to Polistes dominulus, Vespula germanica and Vespa crabro in sera of patients allergic to vespids.

The study was undertaken to investigate the presence of IgE antibodies to Polistes dominulus (PD), Vespula germanica (VG) and Vespa crabro (VC) in a large group of sera belonging to patients sensitized to Vespids in Spain. RAST values showed that although the majority of patients had IgE antibodies to PD, VG and VC, there was a marked predominance of PD. These results were related to the distribution of the insect in the areas where the sera were obtained. Due to geographical and insect distribution differences, the whole area was divided into three zones: Central, East and South. Comparison of the positive RAST values obtained indicated that, although the positivity to PD predominated over VG and this over VC, there were significant differences in percentage positivities to each vespid in the different regions studied. The results of the RAST absorption studies indicated that in most instances patients were originally sensitized to one vespid and were RAST positive to the other venoms due to cross-reactivity. Only in a minority of cases were coexisting antibodies to two insects present. These results show that PD and VG are the important vespids followed to a lesser extent by VC. This study provides relevant information concerning insect distribution sensitivity in a European country.

Animals↗

PubMed1991

Delayed allergic reactions to beta-lactams. Four cases with intolerance to amoxicillin or ampicillin and good tolerance to penicillin G and V.

We present four cases of delayed allergic skin reactions to amoxicillin or ampicillin with good tolerance to benzyl penicillin and phenoxymethyl penicillin. The clinical symptoms reported by the patients, the intradermal skin tests and the controlled challenge results suggested that the mechanism was cellular mediated. In two patients these findings were supported by histopathological studies. Although delayed-type hypersensitivity reactions to beta-lactams with positive skin test seem rare, they can occur to penicillins in allergic patients. The production of these reactions by amoxicillin or ampicillin with good tolerance to benzyl penicillin and phenoxymethyl penicillin emphasizes the role of the side chain in inducing allergic reactions to beta-lactams.

Adult↗

PubMed1991

Differences in serum IgE antibody activity to benzylpenicillin and amoxicillin measured by RAST in a group of penicillin allergic patients.

To determine the influence of the acyl side chain on the IgE antibody specificity of the two most common penicillins inducing allergic reactions in our community, benzylpenicillin (BP) and amoxicillin (AX), IgE positive sera from a group of 24 patients allergic to penicillin were studied. RAST was determined in parallel to benzyl penicilloyl-polylysine (BPO-PLL) and amoxicilloyl-polylysine (AX-PLL) in each serum, and values greater than an established coefficient of variation of 15% were considered as different for either of the haptens used (BP and AX). 16 sera proved to be more positive to BP (Group A), six to AX (Group B) and in two IgE was positive to both haptens with a similar value (Group C). RAST titration concentration effect curves and RAST inhibition studies with a pool of sera from each group (A, B, C) and individual sera showed that most of them were more specific for either BPO or AX, a minority being of similar value to both. These findings indicate that the side chain structure of penicillins is relevant in the constitution of the antigenic determinant, although in some instances the common chemical structure of betalactam is recognised mainly by the IgE antibodies. The clinical relevance of these data needs to be established.

Amoxicillin↗

PubMed1991

Cough in hot pepper workers.

STUDY OBJECTIVE: To determine whether there is an effect on the prevalence of respiratory symptoms, an alteration in lung function, or an increase in the cough threshold to capsaicin among workers chronically exposed to hot chili (Capsicum) peppers. DESIGN: Cross-sectional study of responses to a structured questionnaire, lung function assessed by spirometry and cough threshold to inhalation of capsaicin aerosol in a group of occupationally-exposed Capsicum workers as compared to non-exposed employees of the same work site. SETTING: Spice manufacturing facility. PARTICIPANTS: Twenty-two Capsicum-exposed and 19 nonexposed workers. MEASUREMENTS AND MAIN RESULTS: When evaluated by questionnaire, 13 (59 percent) of the Capsicum-exposed workers reported cough as compared to 4 (21 percent) of the nonexposed workers (p less than 0.05). Baseline FEV1 and FVC did not differ between the two groups. Cough threshold, as assessed by the lowest concentration of inhaled capsaicin eliciting cough, was related to workplace exposure (p = 0.05), displaying a bimodal pattern of higher and lower cough thresholds among the Capsicum workers as compared to a unimodal distribution among the nonexposed workers. Within the exposed group, a higher cough threshold was significantly related to male gender (p = 0.03) and was associated to a lesser extent with dietary preference for hot food (p = 0.09) and cumulative cigarette smoking (p = 0.07). CONCLUSION: Chronic occupational exposure to chili peppers is associated with complaints of cough but does not alone lead to decreased responsiveness of capsaicin-sensitive nerves when assessed by cough threshold. The cough response to capsaicin inhalation may be modified by the effects of multiple, potentially interactive factors.

Adult↗

PubMed1990

Different strains of donor parental lymphoid cells induce different models of chronic graft-versus-host disease in murine (Balb/c x A/J)F1 hybrid hosts.

The induction of a chronic graft-versus-host (cGVH) disease in (Balb/c x A/J)F1 mice by the intravenous injection of either Balb/c or A/J parental lymphoid cells led to the development of two different models of disease. In this paper we compared the clinical aspects and the antigen specificities which recognized the autoantibodies developed by the animals of these two models of cGVH disease. Renal disease, alopecia, and purpura lesions were common in both models, although their frequency and intensity varied between groups. The models were differentiated by two main characteristics. When donor cells were of Balb/c origin, a joint disease similar to rheumatoid arthritis developed in 50% of the animals, and when donor cells were of A/J origin, 25% of the animals developed edema of the front feet, occasionally with loss of the nails, similar to that of scleroderma. Differences among the autoantibodies found in the sera of these two groups of mice were also observed. After the injection of Balb/c lymphoid cells, rheumatoid factors reactive with human and murine IgG were characteristically present (69 and 75%, respectively) and a statistically significant correlation was found between high titers of rheumatoid factor and arthritis (P less than 0.001). Antinuclear antibodies (ANAs) were present in all animals. Anti-dsDNA and anti-histones were positive in 50 and 25%, respectively. Anti-snRNP were detected at a low titer in 35% of the animals. When donor cells were of A/J origin, ANAs were also present in all mice. Anti-dsDNA, anti-histones, and anti-snRNPs antibodies were present in 90, 15, and 65%, respectively. The most outstanding characteristics among anti-snRNPs were the high titers of anti-U1 and anti-U3 detected in 50 and 30%, respectively. Rheumatoid factors reactive with human and murine IgG were positive in 15 and 42% of animals, respectively, but no significant correlation was found between these factors and disease. Our results indicate that the graft-versus-host disease induced in the same F1 strain of mice can be manifested in different forms of connective tissue disease, depending on whether the cells come from one or the other of the parental strains. Furthermore, in this paper the occurrence of rheumatoid factors in mice with cGVH is described for the first time.

Animals↗

PubMed1990

Relation of quantitative coronary lesion measurements to the development of exercise-induced ischemia assessed by exercise echocardiography.

To assess the relation of quantitative measures of coronary stenoses to the development of exercise-induced regional wall motion abnormalities, 34 patients with isolated, single vessel coronary artery lesions and normal wall motion at rest underwent exercise echocardiography and quantitative angiography on the same day. Although all 11 patients with a visually estimated stenosis greater than or equal to 75% had an ischemic response and 10 (91%) of 11 patients with a less than or equal to 25% visually estimated stenosis had a normal response by exercise echocardiography, among 12 patients with a visually estimated stenosis of 50%, 6 (50%) had an ischemic response and 6 (50%) had a normal exercise echocardiogram. Quantitative measurements of stenosis severity distinguished patients with ischemic (group 1) from normal (group 2) exercise echocardiographic responses as follows: minimal luminal diameter (mm), group 1 1.0 +/- 0.4 versus group 2 1.7 +/- 0.4, p less than 0.0001; minimal cross-sectional area (mm2), group 1 0.9 +/- 0.6 versus group 2 2.5 +/- 1.1, p less than 0.0001; percent diameter stenosis, group 1 68.3 +/- 14.2 versus group 2 42.2 +/- 12.1, p less than 0.0001; and percent area stenosis, group 1 87.5 +/- 7.8 versus group 2 64.8 +/- 15.9, p less than 0.0001. These data validate the utility of exercise echocardiography by demonstrating that 1) coronary stenosis severity measured by quantitative angiography is closely related to wall motion abnormalities detected by exercise echocardiography, and 2) exercise echocardiography can be used as a noninvasive means to assess the physiologic significance of coronary artery lesions.

Adult↗

PubMed1990

Allergy to penicillin with good tolerance to other penicillins; study of the incidence in subjects allergic to beta-lactams.

Two hundred and eighty-eight subjects with a history of allergy to penicillin were studied for objective proof of their allergy. On the basis of skin tests, specific IgE antibody measurements and direct challenge tests. 64 patients (22%) were shown objectively to be allergic to one or more penicillins. The following tests were carried out: skin tests to benzyl-penicilloyl poly-L-lysine (BPO-PLL), minor determinant mixture (MDM), amoxycillin (AX) and ampicillin (AMP), in-vitro IgE antibody measurement to benzyl-penicilloyl (BPO) and AX and challenge with benzylpenicillin (BP), phenoxy-methyl-penicillin (PV) and amoxycillin. Forty-four cases were found to respond to benzyl or phenoxymethyl-penicillin, however, 20 were shown to be sensitive to amoxycillin and unresponsive to tests with other penicillins. The contribution that any individual test gave for establishing the diagnosis was 21.8% for skin testing with BPO-PLL, 9.3% with MDM and 12.5% with AX. Nine point three per cent were RAST positive to BPO and 1.5% to AX; 7.8% developed a positive response after challenge to BP, 7.8% to PV and 14% to AX. In 16% of the 64 positive cases more than one test was found to be positive. The challenge tests suggested that not all the penicillin-sensitive subjects had IgE-mediated reactions implying other immunological mechanisms. These results clearly demonstrate the importance of side chain-specific diagnostic reagents and challenge tests. Thirty-one per cent of the positive group or 6.9% of the total group would have been missed in this study using benzyl or phenoxymethyl-penicillin diagnostic reagents alone.

Adolescent↗

PubMed1990

Identification of protein components reactive with anti-PM/Scl autoantibodies.

The PM/Scl antigen from mammalian cells has been characterized as a nucleolar and nucleoplasmic molecular complex containing at least 16 polypeptides ranging in molecular weight from 110 to 20 kD. Of these polypeptides, we have found those of 68, 39 and 20 kD to be in a phosphorilated form. Whereas the entire complex was precipitated by all the anti-PM/Scl sera tested, in immunoblots the antibodies specifically recognized determinants on the 110-kD protein. This protein was immunoprecipitated more preferentially from nucleoli extracts than from total cell extracts. Moreover, this protein disappeared from the immunoprecipitates when treated with DNAse. Likewise, the immunoblot reaction of the specific antibodies with the 110-kD protein was abolished by treatment of the extracts with DNAse and trypsin, and was resistant when extracts were treated with RNAse. Affinity-purified antibodies from this protein selectively stained the nucleoli and the nucleoplasm of the mammalian cells. Moreover, when the cultured cells used in immunofluorescence were treated with DNAse, the affinity purified antibodies from the 110-kD protein gave negative fluorescence. However, when whole anti-PM/Scl sera were used, a nucleolar and nucleoplasmic staining was found. We conclude that the 110-kD protein has at least one of the autoimmunogenic epitopes of the PM/Scl antigen, recognized by all anti-PM/Scl sera tested. Other epitopes differing in their DNAse sensitivity may also be present in the PM/Scl antigen.

Antibody Specificity↗

PubMed1989

Autoantibodies in chronic delta virus infection recognize a common protein of 46 kD in rat forestomach basal cell layer and stellate thymic epithelial cells.

Chronic hepatitis delta virus infection is associated with the presence of autoantibodies to rat forestomach and thymus in approximately 60% of patients' sera. We have characterized the antigen against which these autoantibodies are directed as a protein of 46 kD by immunoblotting studies on rat forestomach and thymus extracts. Normal human sera or sera from patients with other hepatic or non-hepatic autoimmune disorders did not bind to this protein. The immunoblot assay was more sensitive than immunofluorescence. Maximal titre was 1:10,000 versus 1:5120. By techniques of elution of specific antibodies from immunoblots, our results showed that the same antigen was present in both tissues. This antigen did not share common epitopes with hepatitis delta virus (HDV). Patients' sera depleted of basal cell layer and thymic stellate epithelial cell antibodies by absorption with the corresponding tissue extract maintained the HDV antibody titres. The autoimmune phenomena observed in patients with HDV infection seems to be a colateral process induced by the replication of delta virus in the host.

Animals↗

PubMed1988

Characterization of the CB antigen, a DNA-binding protein recognized by autoantibodies and which has a differential expression in lymphoid cells.

We have analyzed the characteristics of the CB Ag, a nuclear protein recognized by autoantibodies. Approximately 4% (12 out of 280) of the antinuclear-positive sera examined contained anti-CB antibodies. By immunofluorescence, these sera brightly stained the nuclei of most cells analyzed, including peripheral lymphocytes, but only dull or no staining was observed in thymocytes or B cells of the bursa of Fabricius. The CB Ag has been characterized as a DNA-binding protein, dissociable from DNA at 1.5 M NaCl, and with a Mr of 40,000 Da. Moreover, the ability of the extracted Ag to bind back to DNA has enabled us to design an ELISA system for its detection.

Adult↗

PubMed1988

Characterization of the antigen reactive with anti-Scl-70 antibodies and its application in an enzyme-linked immunosorbent assay.

The characteristics of the Scl-70 antigen (topoisomerase I) have been analyzed by means of autoantibodies. This antigen is a DNA-binding protein, dissociable from DNA at 0.3M NaCl and bound to a fraction of DNA that is very sensitive to nucleases. The molecular weight of the antigen is 105,000 daltons, whether dissociation conditions are used or not. Using chicken erythrocytes, and taking advantage of the strong interaction of the antigen with hydroxyapatite, we have designed a simple and fast purification protocol that allows the determination of anti-topoisomerase I antibodies by enzyme-linked immunosorbent assay.

Antibodies, Antinuclear↗

PubMed1988

Allergic reactions to vespids: comparison of sensitivities to two species in a Mediterranean area.

We have studied a group of twenty-seven patients who suffer allergic reactions to vespids stings. Specific IgE antibodies to venom extracts from Polistes gallicus and Vespula germanica were measured by RAST, and the crossreactivity between the two venoms was compared using the RAST inhibition technique. We concluded that, in southern Spain, sensitization to P. gallicus was more prevalent than that to V. germanica, with 44% of the subjects in this study reacting to P. gallicus compared with 33% to V. germanica. However, there was a considerable degree of crossreactivity between the two species. It is evident that Polistes is an important species in this area; however, both in Spain and other Mediterranean countries, V. germanica venom is used almost exclusively for diagnosis and immunotherapy.

Adolescent↗

PubMed1987

Anti-NOR 90. A new autoantibody in scleroderma that recognizes a 90-kDa component of the nucleolus-organizing region of chromatin.

We identified a patient (CAG) with scleroderma whose serum contained a high titer of IgG class antibodies that stained nucleoli in a pattern of independent tiny spots. When tested on isolated chromosomes, these antibodies selectively stained the nucleolus-organizing regions (NOR) of chromosomes 13, 14, 15, 21, and 22. These staining patterns were not altered when substrate cells and chromosomes were treated with RNase, 0.1 M HC1, or 4 M urea, but they were abolished by treatment with DNase and trypsin. Immunoblots performed with serum CAG on isolated nucleolar substrates identified a protein antigen of approximately 90 kDa. Antibodies affinity-purified from this protein selectively stained nucleoli and NOR chromosomal regions. Therefore, this protein is the antigen that accounts for the ability of serum CAG to recognize the NOR. In a search for the NOR 90-kDa specificity among 254 patients with various rheumatic diseases, we found nine additional patients whose sera stained metaphase chromosomes selectively at the NOR. Sera from five of them (three with scleroderma, two of unknown diagnosis) recognized a protein that electrophoretically co-migrated with the CAG antigen. Thus, scleroderma is present in at least four of six who appear to have this specificity. We conclude that autoantibodies to the NOR 90-kDa antigen have an association with scleroderma and may be useful diagnostically and as a probe for further studies of the biology of the cell nucleolus.

Autoantibodies↗

PubMed1987

Autoantibodies against the H1(0) subtype of histone H1.

The specificity of antinuclear autoantibodies in a patient with a sensory neuropathy associated with cancer has been analyzed. The autoantibodies recognize the histone H1(0) as shown by its dissociation from DNA, perchloric solubility, electrophoretic mobility in SDS or urea/acid polyacrylamide gels, and by the capacity of purified H1(0) to block the reactivity of these autoantibodies. Almost no reactivity was observed with other subtypes of H1. To our knowledge, this is the first autoantibody described with such specific reactivity for the H1(0) subtype.

Aged↗