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Biomedical subjects

C Juarez

Publications and source records attributed to C Juarez.

54 records · Page 3Linked to original sources
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↗
PubMed1987

Effect of enzymatic treatments on RNP and Sm antigenic reactivities--I. Loss of RNP but increase of Sm antigenic reactivity after RNase treatment of nuclear extract.

Changes of RNP and Sm antigenic reactivities of a nuclear extract after enzymatic treatments were studied and quantified by the ELISA test. After RNase treatment of the nuclear extract, about a 300% increase of the Sm antigenic reactivity and more than a 95% decrease of RNP antigenic reactivity was found. Data from RNP-depleted nuclear extracts and column fractionation show that the increase in Sm antigenic reactivity after RNase treatment mainly comes from the RNP-Sm complex.

Antibodies, Antinuclear↗
PubMed1979

Massive retinal gliosis simulating choroidal melanoma.

A pigmented fundus lesion in a 47-year-old woman gave a positive 32P test result and angiography showed a separate tumor circulation suggesting a diagnosis of choroidal melanoma. Examination after local resection of the tumor revealed massive retinal gliosis, a rare condition not normally considered in the differential diagnosis of choroidal melanoma. We review the clincial and histologic features that differentiate massive retinal gliosis from choroidal melanoma and astrocytic hamartoma.

Choroid Neoplasms↗
PubMedDate not supplied

Clinical course and prognosis of Brucella spondylitis.

A multicentre prospective study of 593 patients with brucellosis, of whom 58 (9.7%) had spondylitis, was performed in order to evaluate the possible clinical, radiological and evolutionary differences in the different segments of the spinal column. Five of the patients with cervical spondylitis (71%) had compression of the medulla or roots, versus just two (11%) in the dorsal group and nine (21%) in the lumbar group (p less than 0.05). There were no other clinical, haematological or biochemical differences between the three spinal segments, and both the serological response and the percentage of positive blood cultures were also similar in the three groups. The patients with cervical and dorsal spondylitis had a significantly higher number of paravertebral and/or epidural masses than those with lumbar spondylitis (p less than 0.05). Seventy-one percent of the patients with cervical spondylitis made unsatisfactory progress, versus 11% and 5% of those in the dorsal and lumbar groups, respectively (p less than 0.05 and p less than 0.001). In conclusion, given the high incidence of paravertebral and/or epidural masses, the neurological involvement, and the high rate of important functional disabilities, cervical spondylitis should be considered to be a very severe complication of brucellosis, and its treatment and follow-up must therefore be energetic and rigorous in order to detect and correct as early as possible compressions of the neural axis and its roots.

Adolescent↗
PubMedDate not supplied

Choroidal occlusive disease in sickle cell hemoglobinopathies.

Two distinct episodes of posterior ciliary artery occlusion were studied in a 32-year-old man with hemoglobin SS disease and multiple episodes of amaurosis fugax. Although posterior ciliary artery occlusions have been observed following photocoagulation of sickle cell retinopathy, their spontaneous evolution in patients with sickling hemoglobinopathies has received little attention. The manifestations of posterior ciliar artery occlusion seen in this case and in other clinical and experimental situations are reviewed. Histopathologic examination of three additional eyes of patients with sickle hemoglobinopathies revealed changes which may have been the result of previous small posterior ciliary artery occlusions or small vessel occlusive disease related to the sickling hemoglobinopathies; these cases are also reported.

Adult↗
PubMedDate not supplied

IgG and IgE antibodies in subjects allergic to penicillins recognize different parts of the penicillin molecule.

BACKGROUND: IgE and IgG antibodies to penicillins can have different specificities. However, this response, including the recognition of the different parts of penicillin, has never been studied in the same subject. OBJECTIVE: Study of the specificity of IgE and IgG antibodies and the relevant parts of the penicillin molecule that contribute to the hapten binding site in sera from human. METHODS: Specific IgE antibodies were determined by RAST and specific IgG antibodies by ELISA. The recognition of the different molecules was studied by inhibition studies. RESULTS: Seven sera with IgG and IgE antibodies to amoxicillin and benzyl penicillin were analyzed. IgE antibodies recognized mainly two different epitopes: in one, the side chain was a relevant part of the epitope, in the other, it was the nuclear portion. IgG antibodies recognized the nuclear portion in all instances. In the same subject, antibodies of different isotype and specificity were found. CONCLUSIONS: Subjects who develop simultaneously IgE and IgG antibodies to penicillins show different specificities. This proves that different populations of antibodies recognize different epitopes.

Antibody Specificity↗
PubMedDate not supplied

Expression of the cutaneous lymphocyte-associated antigen in circulating T cells in drug-allergic reactions.

BACKGROUND: Mechanisms underlying the production of delayed cutaneous reactions to drugs are poorly characterized. The cutaneous lymphocyte-associated antigen (CLA) is a skin-homing T cell receptor that defines T lymphocytes associated with the cutaneous immune response. We studied the percentage and activation phenotype of circulating CLA+ T cells in drug allergic patients and healthy controls. METHODS: PBMCs were isolated from heparinized venous blood by Ficoll density gradient. Lymphocytes were stained for flow cytometry with anti-CLA, anti-CD3 and anti-HLA-DR mAbs. Five-parameter analysis was performed on an Ortho Cytoron Absolute flow cytometer. RESULTS: We found increased percentages of circulating CLA+ T cells in drug-allergic patients compared to controls. Moreover, CLA+ T cells from drug-allergic individuals expressed a higher percentage of the T cell activation marker HLA-DR. CONCLUSIONS: These results suggest that CLA+ T cells may play a role in the pathology of delayed cutaneous reactions to drugs. Further studies are in progress to elucidate the role of skin-homing T cells in allergic reactions to drugs.

Antigens, Differentiation, T-Lymphocyte↗
PubMedDate not supplied

Determination of inflammatory markers in allergic reactions to drugs.

Serum tryptase (Tryp) and eosinophil cationic protein (ECP) and urine N-methylhistamine (N-MH) were quantitated in a group of 13 subjects who had experienced immediate allergic reactions to different drugs. Results indicated that both Tryp and N-MH were involved and the levels were related to the severity of the reaction. Results of serum ECP levels failed to provide relevant information concerning the participation of eosinophils in immediate reactions to drugs.

Adolescent↗
PubMedDate not supplied

Sensitivity to European wasps in a group of allergic patients in Marseille: preliminary results.

The wasp Polistes dominulus (PD), the yellow jacket Vespula germanica (VG) and the hornet Vespa crabro (VC) are allergenically important social wasps found in Europe. Serum samples obtained from allergic subjects in Marseille were studied in order to determine the positivity by RAST to these venoms. All the sera studied had IgE antibodies to at least one of the wasp venoms tested and 50% had IgE antibodies that reacted with more than one venom. The presence in some sera of IgE antibodies to the venoms of all three wasps and RAST inhibition studies suggested that the three venoms were relevant in the area studied and that most sera were positive to the three venoms due to allergenic cross-reactivity. However, inhibition studies revealed that 2 patients may have had antibodies that did not cross-react and that were specific for the venom of only one species.

Adolescent↗