Biomedical subjects
Publications and source records attributed to J M Von Feldt.
Medical treatment of low back pain is at best palliative. While no drugs are specifically labeled for back pain treatment, analgesics, muscle relaxants, and corticosteroids are used in practice to augment rest and exercise programs. Invasive therapy remains contentious. This article reviews the available literature on the various pharmacologic therapies. In addition, newly postulated outcome measures for future back pain studies are discussed.
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OBJECTIVE: To evaluate the utility of polymerase chain reaction (PCR) amplification in detecting DNA from venereal-associated microorganisms in the synovial fluid of patients with inflammatory arthritis. METHODS: Oligonucleotide primers were developed for nested PCR based on Chlamydia, Ureaplasma, and Neisseria DNA sequences. PCR products were detected by gel electrophoresis and dot-blot hybridization. Primers specific for the target bacterial DNA were used to search for bacterial DNA in 61 synovial fluid specimens from patients with inflammatory arthritis, including several clinically associated with venereal infection. RESULTS: Five of the 61 synovial fluid specimens were positive for Neisseria gonorrhoeae DNA. Four of the 5 patients had clinical diagnoses of gonococcal arthritis; the other patient had an unexplained monarthritis. One specimen from a patient with a clinical diagnosis of gonococcal arthritis was negative for N gonorrhoeae. Three of the 61 specimens were positive for Chlamydia DNA. Two were derived from patients with clinical diagnoses of reactive arthritis or Reiter's syndrome, and 1 was from a patient with unexplained monarthritis. One of the 61 specimens was positive from Ureaplasma DNA; this sample was from a patient with a clinical diagnosis of Reiter's syndrome. In an additional patient with Reiter's syndrome, Ureaplasma DNA was also found in prostate biopsy tissue and a urine sample obtained after prostate massage (synovial fluid not available). CONCLUSION: These data support the classification of these 3 venereal-associated arthritides as infectious processes, and suggest that PCR for bacterial DNA is a useful method for detecting infectious agents in synovial fluid.
Several syndromes involving antiphospholipid antibodies have been described in the literature. Although the varied clinical manifestations have been well delineated, the vascular pathophysiology in patients with these antibodies remains unclear. Vascular damage is often described as a vasculopathy; however, several case reports have described an associated vasculitis. We report two patients with manifestations of antiphospholipid antibody syndrome (APLS) and concurrent vasculitis. The first patient, a 42-year-old man, presented with abdominal pain and fevers. The second patient, a 39-year-old man, presented with fever and testicular pain. Both were ultimately felt to have polyarteritis nodosa associated with APLS. Their complicated hospital courses and difficulties we encountered in diagnosing and treating them are discussed. The literature describing other cases of vasculitis associated with antiphospholipid antibody syndrome is reviewed. Whether the presence of antiphospholipid antibodies favors the development of vasculitis or vice versa is not clear. Further studies are needed to address this question and to determine optimal therapeutic regimens in these critically ill patients.
Synovial tissue is rarely available from patients with early synovitis, with the exception of synovial biopsies. However, T cell populations early in the development of synovitis may be enriched in antigen-specific cells and critical to disease pathogenesis. To investigate the T cell repertoire in early synovitis, we utilized a PCR protocol for detection of T cell receptor (TCR) transcripts present in small amounts of synovial tissue. To expand the substrate for PCR, preamplification of cDNA was performed with a 3' constant region primer plus either a mixture of variable region primers or random hexanucleotides. Utilizing this method improved the sensitivity of detection. This technique is applied here to the analysis of TCR transcripts in synovial biopsies from individuals with early rheumatoid arthritis (RA) and non-RA synovitis. TCR alpha-chain transcripts were detectable in 5/5 RA and 4/4 non-RA specimens evaluated, with beta-chain transcripts detected in 4/5 early RA and 4/4 non-RA specimens evaluated. Confirmation of transcripts by sequencing of cloned PCR products verified the specificity of amplification. The most frequently expressed TCR V region families in early RA synovitis were V alpha 11, V alpha 14, V alpha 28, V beta 7, V beta 9 and V beta 17. Several of these V regions have previously been implicated in studies of chronic RA synovitis. J alpha and J beta region usage was similar to that seen in chronic RA, and conserved N region motifs were apparent. We conclude that it is possible to detect TCR transcripts in small synovial biopsies from individuals with early arthritis.(ABSTRACT TRUNCATED AT 250 WORDS)
Systemic lupus erythematosus (SLE) is a multisystem disease that predominantly affects women. Probable causative factors include genetic predisposition, complement deficiencies, persistence of antigen, drugs, and environmental factors. The widely varying presentations of SLE include skin, musculoskeletal, cardiovascular, renal, pulmonary, gastrointestinal, neuropsychiatric, systemic, hematologic, and immunologic manifestations. Milder symptoms can be managed with nonsteroidal anti-inflammatory drugs and antimalarial agents. Corticosteroids and cytotoxic drugs are given in more severe disease.
In most western countries, scurvy has become a rare clinical entity. However, it may still be encountered in selected situations. It can mimic connective tissue disease, because of multiorgan involvement. Panniculitis has not previously been described in association with scurvy.
The increase in the incidence of HIV-1 infection in women of child bearing age has resulted in a surge in the number of cases of pediatric AIDS. The World Health Organization (WHO) has estimated that the number of cases of pediatric AIDS worldwide will be at least 10 million by the year 2000. This alarming statistic underscores the need for accurate prediction and diagnosis of pediatric HIV-1 infection which is of paramount importance for the initiation of effective therapeutic interventions. Since circulating maternal anti-HIV-1 antibody persists in the baby for up to 21 months, early conventional serological diagnosis of infection is not possible. Other methods for diagnosis of HIV-1 infection in a child less than 2 years of age have been utilized including the polymerase chain reaction (PCR), measurements of the HIV-1 p24 core protein and anti-HIV-1 IgA, as well in vitro measurements of antibody producing cells. In addition, the ability to predict HIV-1 infection in the child based upon maternal humoral immune responses to the envelope glycoprotein has also been suggested. This review summarizes the recent serological, biological and molecular methodologies used to predict and diagnose pediatric HIV-1 infection and AIDS.
Development of small molecular mimics of larger polypeptide ligands is an important approach to pharmacophore design. One strategy for the development of such mimics is analysis of alternative ligands that bind to the same site as the native ligand. These allow examination of the structural and chemical constraints for binding within the setting of diverse backbone geometries. The use of antireceptor antibodies as alternative ligands has allowed the development of biologically active peptides in several ligand-receptor systems. This technology has been applied to the study of interactions between human granulocyte-macrophage colony-stimulating factor (GM-CSF) and its receptor (GM-CSFR). GM-CSF is one of a family of signal-transducing cytokines and growth factors characterized by a four-helix bundle core structure. The GM-CSFR is comprised of an alpha-chain (GM-CSFR alpha) specific for GM-CSF, and a beta-chain (beta c) shared with the interleukin-3 and interleukin-5 receptors. At least two sites on GM-CSF have been implicated in the GM-CSF-GM-CSFR alpha/beta c ternary complex. In studies summarized here, synthetic peptide analogs of GM-CSF sequences were designed and used to map neutralizing epitopes. One neutralizing epitope corresponded to the A helix of GM-CSF, and a synthetic analog displayed biological activity as a GM-CSF antagonist in vitro, suggesting interaction with the GM-CSFR alpha/beta c complex. A second peptide comprising the B and C helices was recognized by monoclonal neutralizing antibodies and similarly displayed antagonist activity. Recombinant antibody (rAb) technology was also employed. An expression library of rAbs from mice immunized with neutralizing anti-GM-CSF antibodies was developed and screened with a neutralizing anti-GM-CSF monoclonal antibody. One clone which displayed receptor binding activity exhibited structural similarity with epitopes on GM-CSF previously implicated as interaction sites with the neutralizing monoclonal antibody. A synthetic peptide analog of the rAb inhibited GM-CSF bioactivity. Critical contact residues were predicted on the basis of structural similarity of the rAb peptide and GM-CSF. These studies indicate the feasibility of using rAbs in bioactive peptide design, providing lead compounds and information regarding contact residues for drug design.
Immunotherapy against autoreactive T-cell receptors (TCRs) has been reported to have promise in several animal models of autoimmune diseases. Facilitated DNA inoculation has many potential advantages as a modality for development of specific immune responses. Specifically, this technology is able to deliver exogenous antigens for processing via both the endogenous pathway, with subsequent presentation by class-I major histocompatibility (MHC) antigens, and the exogenous pathway, with subsequent presentation by class-II MHC antigens. This allows for induction of both arms of the cellular immune system. These cellular immune responses may be particularly important in targeting and controlling pathogenic cell populations. The application of this technology to the treatment of human autoimmune diseases depends on the availability of readily manipulated systems for the evaluation of specific interventions. Here we report the full length cloning and expression of TCRs from rheumatoid arthritis synovial tissue. These were developed by recombinant polymerase chain reaction, cloning and retroviral transduction into a TCR-alpha/beta-negative murine T-cell hybridoma. Reconstitution of CD3 expression was confirmed by flow cytometry. Similar constructs have been developed for TCR-based immunotherapy by facilitated inoculation of DNA intramuscularly. Preliminary analysis of immune responses in mice indicates that these constructs elicit anti-TCR responses. These studies indicate the ability to reconstitute expression of potentially autoreactive human TCRs in a model system wherein specific immune responses elicited against these TCRs by various immunogens can be evaluated.
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The CNS afflictions in AIDS are myriad and suggest a tropism of HIV to neural tissue. Ocular involvement is a frequent manifestation of the HIV infection, resulting in a high incidence of blindness within this patient population. Ocular lesions include cotton wool spots, presumably from HIV-induced microvasculopathy, retinal hemorrhage in cytomegalovirus retinitis and conjunctival Kaposi's sarcoma. These manifestations have been noted in up to 71% of AIDS patients. In fact, ocular disease is often the presenting symptom in an HIV-infected individual. Despite the high incidence of ocular involvement in AIDS patients, the etiology and pathogenesis of these manifestations are not well understood. The immunosuppressive action of HIV is the most likely primary cause for the development of ocular complications in AIDS. Here we review some of the important immunological and pathological features of AIDS affliction in the eye.
Granulocyte/macrophage colony-stimulating factor (GM-CSF) plays a critical role in myeloid differentiation and in several immune and inflammatory processes. GM-CSF binds to specific cellular receptors (GM-CSFR) which belong to a recently described supergene family. These receptors are potential targets for pharmacologic design and such design depends on a molecular understanding of ligand-receptor interactions. We present our initial studies evaluating the potential active sites of the molecule. The sites on the GM-CSF molecule that were studied represent two alpha-helices predicted to be critical for GM-CSF activity, as implicated by human-murine chimeric molecule studies. These helices are predicted to be adjacent in native GM-CSF. Peptides corresponding to amino acids 17-31 and 78-99 of GM-CSF were synthesized and cross-linked to one another in two different orientations. The ability of anti-GM-CSF to bind the individual and complexed peptides was evaluated by both ELISA and radioimmunoassay. Significant binding to all peptides was demonstrated. A preferred orientation of the two peptides was apparent, and this agreed with the predicted model structures. Antibodies were developed against the coupled peptides, and these demonstrated significant cross-reactivity with recombinant human GM-CSF. Additionally, analyses of anti-peptide antisera binding studies predict these two amino acid sequences to lie in parallel planes to one another in the native human GM-CSF molecule.
OBJECTIVE: To search for molecular evidence of Chlamydial infection in systemic lupus erythematosus (SLE) subjects and to assess if there is an association of this infectious agent with coronary artery calcification (CAC), a marker of total atherosclerotic burden. METHODS: 28 SLE subjects had blood samples drawn and DNA extracted from peripheral blood mononuclear cells (PBMC) and an electron beam computed tomography (EBCT) scan. Polymerase chain reaction (PCR) analysis was performed for Chlamydia trachomatis 16srRNA and major outer membrane protein (MOMP) and for C. pneumoniae 16srRNA, MOMP, as well as nested PCR for MOMP. RESULTS: Four of 28 subjects (14.2%) had evidence of C. pneumoniae nucleic acid in PBMC. The 16srRNA primers detected C. pneumoniae in one patient (3.57%) and the nested PCR MOMP primers in 3 subjects (10.71%). None were positive for Chlamydia trachomatis. Two of the 4 subjects with C. pneumoniae DNA had abnormal EBCT scans and 2/11 (18.3%) subjects with abnormal EBCT were positive for C. pneumoniae. There were significant associations of C. pneumoniae DNA with smoking (OR = 3) and corticosteroid use. The odds ratio for subjects with abnormal CAC and detectable C. pneumoniae was 1.67. CONCLUSION: This pilot study demonstrates for the first time that C. pneumoniae DNA can be identified in the PBMC of some SLE subjects and there may be an association with CAC. Smoking may be an additional risk factor for infection in this population. Determination of pathogenicity of this organism in atherosclerotic coronary vascular disease in SLE will require further study.