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Biomedical subjects

R M Bernstein

Publications and source records attributed to R M Bernstein.

At least 55 records · Page 3Linked to original sources
PubMed1994

Evolutionary conservation and molecular cloning of the recombinase activating gene 1.

A 700-bp fragment of the recombinase activating gene 1 (RAG-1) was cloned from several evolutionarily distant (sandbar shark, paddlefish, goldfish, axolotl and pig) species using PCR. The nucleotide and deduced amino acid sequences revealed a highly conserved region that has remained essentially unaltered during 400 million years of evolution; e.g., shark and human sequences were 75% identical at the nucleic acid level and 87% as protein. The RAG-1 mRNA levels in the shark were analyzed using semi-quantitative PCR to reveal expression patterns contrary to normal mammalian expression. These results establish that the genetic mechanisms for Ig gene rearrangement are present in all extant gnathanstomes.

Amino Acid Sequence↗
PubMed1994

Autoantibodies to the alpha/beta T-cell receptors in human immunodeficiency virus infection: dysregulation and mimicry.

Autoimmune reactivity is a consequence of infection with human immunodeficiency virus (HIV). We studied serological cross-reactions of purified pooled IgG from sera of HIV-infected individuals by using nested sets of synthetic overlapping peptides duplicating the covalent structures of T-cell receptors (TCRs) and immunoglobulin light chains and report that two processes of autoantibody production occur. (i) IgG autoantibodies to putative regulatory variable domain CDR1 and FR3 epitopes (where CDR is complementarity-determining region and FR is framework region) are present in pooled IgG from HIV-infected individuals at levels 10-fold greater than that in pooled IgG from healthy humans. (ii) Anti-TCR autoimmunization involves antigenic mimicry between a conserved peptide stretch of the major neutralizing V3 loop determinant of HIV-1 gp120 and the conserved FR4 segment of the TCR V beta. Affinity-purified antibodies to the synthetic V3 loop peptide bound to a recombinant single-chain TCR and to a synthetic TCR joining segment peptide containing the FR4 sequence. Conversely, affinity-purified autoantibodies from pooled IgG from HIV-infected individuals to the TCR peptide bound the V3 loop peptide and a single-chain TCR. Inhibition studies indicated that the cross-reactive immunizing antigen was the V3 loop. These results bear upon the impact of HIV infection on immune regulation and on the selection of peptides for vaccine development.

Amino Acid Sequence↗
PubMed1994

Trimeric structure of human proliferating cell nuclear antigen. Implications for enzymatic function and autoantibody recognition.

The proliferating cell nuclear Ag (PCNA) is a DNA replication factor postulated to function as a sliding clamp around DNA. PCNA is also a target for autoimmunity in systemic lupus erythematosus. The autoantigenicity of PCNA is highly conformation-dependent, and reaction with most anti-PCNA sera requires a nearly full-length PCNA molecule. Here we describe the use of gel filtration and glycerol gradient sedimentation to analyze the native structure and size of PCNA. PCNA from three sources was studied (PCNA from HeLa cells, PCNA purified after its overexpression in bacteria, and PCNA produced in the wheat germ cell-free translation system) as well as mutant forms of PCNA translated in vitro. In each case, full-length PCNA behaved as a trimer. Analysis of mutant proteins revealed a correlation between the trimeric form and binding to the common type of human anti-PCNA autoantibody, suggesting that the Abs are specific for the active form of the protein. These findings are consistent with the idea that autoantibodies are generated as a response to native Ag and provide experimental support for the hypothesis that PCNA serves its processive function in DNA replication as a trimeric ring structure.

Autoantibodies↗
PubMed1994

Construction and serological characterization of a recombinant human single chain T cell receptor.

A single chain T cell receptor (scTcr) was constructed from the complete V alpha and V beta regions of Jurkat T-cell receptor alpha/beta chain genes using molecular cloning techniques. The recombinant scTcr reacted with a panel of rabbit antisera generated against synthetic 16-mer peptides duplicating the amino acid sequence of Jurkat V alpha and beta chains but not with antisera directed against peptides from the constant domain. Autoantibodies present in sera from systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) patients bound the scTcr in ELISA assays. The recombinant scTcr described here should prove to be a useful reagent with which to study T-cell receptor activity in serological and functional assays.

Autoantibodies↗
PubMed1994

Autoreactive epitope profiles of the proliferating cell nuclear antigen define two classes of autoantibodies.

The proliferating cell nuclear antigen (PCNA) is a conserved protein required for cellular DNA replication. PCNA was first recognized using serum from the autoimmune disease SLE. To analyze the regions on PCNA that confer autoantibody binding, we modified the cDNA encoding full-length PCNA to generate a series of amino terminal, carboxyl terminal and internally deleted constructs, which were transcribed and then translated in vitro using the wheat germ cell-free translation system. An immunoprecipitation assay was used to study the ability of these mutated forms of PCNA to bind anti-PCNA Abs from patients with SLE. Eight of the ten sera studied required a protein of nearly full length for binding: antigenicity was abrogated by removal of 39 amino acids from the amino terminus, by various internal deletions, or by the removal of 15 (but not 11) amino acids from the carboxyl terminus. The remaining two sera exhibited an Ab-binding specificity to the carboxyl-terminally truncated proteins similar to that of the majority of anti-PCNA sera, but their specificity was different in the amino terminus: these sera were able to recognize PCNA lacking over 40% of sequence in the amino terminus, but they did not bind proteins with short internal deletions in that region. Thus, these epitopes appear to be conformational and distinguish two classes of autoimmune sera.

Autoantibodies↗
PubMed1994

Autoantibodies to myeloperoxidase in idiopathic and drug-induced systemic lupus erythematosus and vasculitis.

Circulating antibodies to myeloperoxidase (MPO) have been described in a variety of vasculitic syndromes, drug-induced SLE and drug-induced nephritis. We have examined the autoantibody profile in acute sera from patients with antineutrophil cytoplasmic antibody-positive vasculitis (n = 8), drug-induced nephritis (n = 4), drug-induced lupus (n = 7), SLE (n = 27) and nephritis-associated with SLE (n = 17). Significant binding to purified MPO in ELISA was given by all sera from patients with vasculitis and drug-induced nephritis but ANA sought by indirect immunofluorescence on HEp-2 cells were not detected. Both anti-MPO and ANA were found in sera from patients with drug-induced lupus. Sera from patients with SLE or SLE nephritis did not contain high titres of anti-MPO antibodies but invariably contained ANA. Anti-MPO antibodies of both IgG and IgM classes were present in all sera from patients with drug-induced disease. Although the number of samples tested was small, sera from patients with drug-induced nephritis showed significantly greater median % binding of IgM to MPO compared with drug-induced SLE. Binding to MPO by IgG in these sera was not significantly different. These findings suggest that the mechanism of interaction between hydralazine and the immune system in the two drug-induced autoimmune diseases studied may contribute to their distinct clinical features.

Adolescent↗
PubMed1994

HLA-DP does not contribute towards susceptibility to systemic lupus erythematosus.

OBJECTIVES: To determine whether HLA-DP genes are involved in determining susceptibility to systemic lupus erythematosus (SLE). METHODS: HLA-DPA1 and DPB1 genes were amplified by PCR of DNA samples from a panel of patients with SLE and normal controls. Amplified DNA was blotted on to nylon filters and probed with sequence-specific oligonucleotide (SSO) probes. RESULTS: No DPA1 or DPB1 allele was significantly associated with SLE, or with any immunological or clinical subset of SLE. Evidence was found for only limited linkage disequilibrium between HLA-DP and HLA-DQ/DR variants, and none between HLA-DP and the TAP2 gene. CONCLUSIONS: These data indicate that HLA-DP genes do not contribute towards determining susceptibility to SLE.

Adolescent↗
PubMed1994

A prospective study of psychiatric disorder and cognitive function in systemic lupus erythematosus.

OBJECTIVES: To investigate change in psychiatric disorder and change in cognitive function in patients with systemic lupus erythematosus (SLE) assessed on two occasions two years apart. METHODS: A prospective cohort study of 49 patients with SLE using standardised psychiatric and clinical research methods. RESULTS: The point prevalence of psychiatric disorder (20% and 24%), and of cognitive impairment (23% and 18%), was similar at first and second interview for the whole group. There was, however, considerable change in individual patient's psychiatric status and cognitive function: only 1/9 patients with impairment on two or more cognitive tests at first interview was still impaired at second interview. Change in cognitive function appeared to mirror change in psychiatric status. CONCLUSIONS: These findings suggest that the previously reported high prevalence of cognitive impairment in SLE may be explained by coexisting psychiatric disorder, rather than reflecting subclinical central nervous system (CNS) involvement.

Adult↗
PubMed1994

Prompting physicians for cost-effective test ordering in the low prevalence conditions of family medicine.

We have developed a computerized prompting system for test ordering which we feel will decrease the cost of investigations and at the same time promote an evidence based learning approach to test ordering. Prompting systems have been shown to be cost-effective but suffer from many disadvantages in the family practice setting. They tend to be difficult to modify by the user and contingent on an inflexible rule based structure. Many suggestions are ignored implying that they are not relevant. In family practice most conditions are of low prevalence. Prompting for test ordering where the pre-test likelihood of disease is small will result in a large number of false positives and many unnecessary repeat or confirmatory investigations and attendant anxiety unless the prompting system is specifically designed to be used in a low prevalence environment. PROMPTOR-FM (PRObabilistic Method of Prompting for Test ORdering in Family Medicine) was developed to overcome these perceived difficulties. It allows the physician to rapidly calculate the positive and negative predictive values of a test being considered based on the clinical index of suspicion. The physician is able to repeat the calculations and compare the results with previous calculations. By using PROMPTOR-FM repetitively, the clinician can learn to balance the risk of "missing" a rare but serious condition against the risk of falsely identifying disease with its downstream hazards and costs of further investigation. Prompting for test ordering is therefore uniquely tailored to each patient's situation.

Artificial Intelligence↗
PubMed1993

Preliminary criteria for the classification of Sjögren's syndrome. Results of a prospective concerted action supported by the European Community.

OBJECTIVE: Different sets of diagnostic criteria have been proposed for Sjögren's syndrome (SS), but none have been validated with a large series of patients or in a multicenter study. We conducted the present study involving 26 centers from 12 countries (11 in Europe, plus Israel), with the goals of reaching a consensus on the diagnostic procedures for SS and defining classification criteria to be used in epidemiologic surveys and adopted by the scientific community. METHODS: The study protocol was subdivided into two parts. For part I, questionnaires regarding both ocular and oral involvement were developed; they included 13 questions and 7 questions, respectively. For part II a limited set of diagnostic tests was selected, and the exact procedure to be followed in performing these tests was defined. Part I of the study included 240 patients with primary SS and 240 age- and sex-matched controls. Two hundred forty-six patients with primary SS, 201 with secondary SS, 113 with connective tissue diseases but without associated SS, and 133 control patients were studied in part II. RESULTS: The study resulted in (a) the validation of a simple 6-item questionnaire for determination of dry eyes and dry mouth, which showed good discriminant power between patients and controls, to be used in the initial screening for sicca syndrome; and (b) the definition of a new set of criteria for the classification of SS. The sensitivity and specificity of the criteria in correctly identifying patients with either the primary or the secondary variant of SS were also determined. CONCLUSION: Using the findings of this prospective multicenter European study, general agreement can be reached on the diagnostic procedures to be used for patients with SS. Final validation of the preliminary classification criteria for SS is underway.

Connective Tissue Diseases↗
PubMed1993

HLA-DQ, DR and complement C4 variants in systemic lupus erythematosus.

We have defined HLA-DQA, DQB, DR and complement C4 variants in 92 subjects with SLE and 73 controls. Subjects with SLE showed an increased frequency of HLA-DQA*0501 (P < 0.01 corrected, odds ratio (OR) = 4.97; 95% C.I. = 2.52-9.81), DR3 (P < 0.001, OR = 3.18; 95% C.I. = 1.67-6.04) and C4A*Q0 (P < 0.05, OR = 1.91; 95% C.I. = 0.999-3.65) vs controls. These increases were particularly marked in those subjects positive for antibodies to both Ro and La. HLA-DQB*0501 (P < 0.01 corrected, OR = 0.03), DQA*0101 (P = 0.0012 uncorrected, OR = 0.23) and DR7 (P = 0.0018 uncorrected, OR = 0.28) were decreased in frequency in SLE. SLE patients with disease onset prior to age 30 yr were more likely to possess a DR3-bearing haplotype (P < 0.05 corrected) than those with onset after age 30 yr. No significant associations were found in patients with circulating antibodies to double-stranded DNA, Ro alone, U1 RNP, Sm or in those SLE patients with renal disease or vasculitis. The different associations found in different clinical and immunological subsets of SLE support the concept that SLE contains a variety of immunogenetic subgroups. Analysis of the associations between SLE and DR3, DQA*0501 and C4A*Q0 using the empirical logistic test suggests that the association of SLE with HLA-DQA*0501 is likely to be primary to the associations with both DR3 and C4A*Q0 (P < 0.001). Our results therefore raise the possibility that genes within the HLA-DQ region may have a direct effect upon susceptibility to SLE.

Adolescent↗
PubMed1993

Transverse myelitis as the presentation of Jo-1 antibody syndrome (myositis and fibrosing alveolitis) in long-standing ulcerative colitis.

A 32-yr-old woman with long-standing ulcerative colitis developed paraesthesiae, sensory loss and muscle weakness shown by magnetic resonance scan to be due to transverse myelitis in the cervical spinal cord. More than 12 months later, she developed dermatomyositis and fibrosing alveolitis and was found to have the Jo-1 antibody. Her condition worsened despite high dose oral prednisolone but improved following intravenous methylprednisolone, immunosuppressive therapy and plasma exchange. This is the first reported case of a neurological presentation of the Jo-1 antibody syndrome. We speculate that the association with ulcerative colitis may have been causal rather than coincidental and suggest that plasma exchange should be considered together with aggressive immunosuppression in seriously ill patients with this disease.

Adult↗
PubMed1993

Anti-P antibodies are associated with psychiatric and focal cerebral disorders in patients with systemic lupus erythematosus.

In a cross-sectional study, 62 patients with systemic lupus erythematosus were assessed using standardized psychiatric and psychological methods; systemic disease activity was scored using the British Isles Lupus Assessment Group and the Lupus Activity Criteria Count indices. IgG and IgM anti-P antibodies were measured by ELISA using a synthetic 22 amino acid peptide as the relevant antigen. IgG and IgM anti-P antibodies were significantly associated with neuropsychiatric disorders (psychiatric and neurological) but failed to distinguish patients with psychiatric disorders from those with neurological disorders. These antibodies were not associated with cognitive impairment or systemic disease activity.

Antibodies↗
PubMed1993

Antibody to mycobacterial 65-kD heat shock protein in commercial antisera.

Inhibition ELISA and immunoblotting were used to examine the antigenic cross-reactivity claimed to exist between mycobacterial 65-kD heat shock protein (hsp65) and human lactoferrin. Commercially available anti-lactoferrin antibodies produced using either Freund's complete (FCA) or Freund's incomplete adjuvant were tested for binding to recombinant mycobacterial hsp65. Both antibody preparations showed reactivity with hsp65, this being greater with the antibody produced using FCA. However, we found no evidence of a cross-reaction. Lactoferrin failed to inhibit anti-hsp65 reactivity, while hsp65 itself did. Affinity purified anti-lactoferrin antibody showed no reaction with hsp65 by ELISA or immunoblotting. These data suggest that commercial anti-lactoferrin preparations are contaminated with antibodies to hsp65. A commercial anti-albumin antibody also bound to hsp65 in ELISA, so this may be a more general phenomenon.

Animals↗