Evaluation of the recombinant 38-kilodalton antigen of Mycobacterium tuberculosis as a potential immunodiagnostic reagent

The diagnosis of infection caused by Mycobacterium tuberculosis is of increased public health concern following increases in the number of cases in developed countries and major increases in developing countries associated with the spread of human immunodeficiency virus (HIV) infection. The specificity of purified protein derivative skin testing for the detection of infection is compromised by exposure to environmental mycobacteria. Examination of sputum detects the most infectious patients, but not those with extrapulmonary disease. The 38-kDa antigen of M. tuberculosis contains two M. tuberculosis-specific B-cell epitopes. We overexpressed the gene for this antigen in Escherichia coli and evaluated the recombinant product in in vitro assays of T-cell function and as a target for the antibody response in humans. The sensitivity and specificity of the antigen as a skin test reagent were also assessed in outbred guinea pigs. We found that 69% of healthy sensitized humans recognize the antigen in vitro, as manifested by both cell proliferation and the production of gamma interferon. Untreated patients initially have a lower frequency of response (38%); this recovers to 72% during therapy. A total of 292 patients (20 with HIV coinfection) and 58 controls were examined for production of antibody to the 38-kDa antigen by using a commercially available kit. The sensitivity of the test in comparison with that of culture was 72.6%, and the specificity was 94.9%. The antigen was also tested for its ability to induce skin reactions in outbred guinea pigs sensitized by various mycobacterial species. The antigen provoked significant skin reactions in M. tuberculosis-, M. bovis BCG-, and M. intracellulare-sensitized animals. The significance of these findings and the usefulness of this antigen in immunodiagnosis are discussed.     

Orbital venous approach to the cavernous sinus: an analysis of the facial and orbital venous system

Carotid-cavernous fistulas are abnormal communications between the internal carotid artery and the cavernous sinus produced by a rupture of the wall of the carotid artery or one of its branches into the sinus. Extradural branches of the internal or external carotid arteries may communicate with the cavernous sinus, producing proptosis, progressive glaucoma, and ocular vascular engorgement. Various approaches to obliterate these fistulas have evolved, many of which carry high morbidity or are precluded by anatomical considerations. Analysis of the venous anatomy of the orbit and face, including human cadaver dissections, reveals a new and safe approach to the cavernous sinus, requiring microsurgical isolation and cannulation of the superior ophthalmic vein through an anterior orbital approach. Selective embolization of a carotid-cavernous fistula can be performed successfully through this route. We present pertinent anatomy and technical considerations and the successful clinical application of these principles. Surgeons familiar with craniofacial anatomy and microvascular techniques can apply these principles and play an active role in the treatment of these complex problems.     

Prevention of autoimmunity in nonobese diabetic (NOD) mice by neonatal transfer of allogeneic thymic macrophages

Nonobese diabetic (NOD) mice spontaneously develop insulin dependent diabetes mellitus. The disease results from an autoimmune process which involves mononuclear cells surrounding and eventually infiltrating the pancreatic islets of Langerhans. Macrophages are thought to be the first cells to infiltrate the islets and are actively involved in the disease process because diabetes is prevented if host macrophages are depleted or inactivated. Several lines of evidence also suggest that NOD macrophages are phenotypically and functionally abnormal. In this study, allogeneic (CBA) macrophages derived from the thymus were inoculated into newborn NOD mice and these were followed for more than 250 days. Spontaneous diabetes was significantly reduced in female NOD mice (6% diabetic versus 45% of controls). Insulitis was also significantly reduced in both male and female mice compared to their control counterparts, and in most cases there were virtually no inflammatory cells in the pancreas. Allogeneic skin grafting and mixed leukocyte cultures indicated that the recipients were not tolerant of donor antigens, and donor-derived cells were not detected in the lymphoid tissues by either flow cytometry or immunohistochemistry. The results show that macrophages from diabetes-resistant donors will prevent insulitis and diabetes in most recipients, however, the mechanism for the protection is unclear, but does not appear to be due to long-term tolerance induction.     

Political correctness and academic principles: a reply to Simpson

The author discusses Christopher Simpson's (1996) article, 'Elisabeth Noelle-Neumann's 'Spiral of Silence' and the Historical Context of Communication Theory.' He questions the relevance of biographical data for the evaluation of scientific theories and methods, and analyzes the rhetorical structure of Simpson's arguments. He concludes that Simpson's claims about the influence of Noelle's biography on her scholarly work are not grounded in evidence.     

Outcome of rheumatoid arthritis and psoriasis following autologous stem cell transplantation for hematologic malignancy

Based on successful results in animal models, it has been proposed that high-dose myeloablative therapy followed by autologous bone marrow or stem cell transplantation (ABMT/ASCT) may cure autoimmune disease. The coexistence of autoimmune disease and hematologic malignancy provides an opportunity to examine the response of autoimmune disease to ABMT or ASCT. We describe 4 patients with autoimmune disease (3 with psoriasis and 1 with rheumatoid arthritis) and hematologic malignancy. In each patient, the autoimmune disease remitted posttransplantation, but, in 4 patients with long-term followup, it recurred at 8-24 months. The earliest relapse occurred in a patient treated with interferon-alpha. Our experience suggests that a single autograft with unpurged stem cells is unlikely to cure autoimmune disease, but that other strategies building on this approach are worthy of investigation.     

Kinetics of modification of the mitochondrial succinate-ubiquinone reductase by 5,5''-dithiobis-(2-nitro-benzoic acid)

In the present study, we examined the effect of the thromboxane/prostaglandin endoperoxide analogue U46619 on proliferation and hypertrophy in cultured rat vascular smooth muscle cells and the roles of protein kinase C and transforming growth factor-beta (TGF-beta) in the mediation of the hypertrophic response to U46619. Since an increase in basic fibroblast growth factor (bFGF) was previously shown to mediate the hypertrophic response to U46619, we also assessed the relationship between bFGF and TGF-beta in the expression of U46619 actions. U46619 increased [35S]methionine incorporation into protein and protein content of vascular smooth muscle cells but had no effect on cell number. A role for TGF-beta was supported by the following observations: (1) exogenous human TGF-beta 1 increased protein synthesis; (2) antibody to TGF-beta blocked both TGF-beta- and U46619-induced increases in protein content; (3) U46619 increased active and total TGF-beta bioactivities; and (4) the actions of U46619 on protein content and TGF-beta bioactivity were blocked by the thromboxane/prostaglandin endoperoxide receptor antagonist SQ 29,548. Previous observations had demonstrated a role for bFGF in the expression of U46619 actions on protein synthesis. Results of the present study suggest that TGF-beta and bFGF interact in mediating the protein synthetic response to U46619. First, the concentration of exogenous TGF-beta (10 pmol/L) alone required to produce a protein synthetic response equivalent to that induced by U46619 was much higher than the concentration of endogenous active TGF-beta that accumulated in the media in response to U46619 (0.7 pmol/L). Second, bFGF (20 ng/mL) increased total TGF-beta bioactivity and stimulated protein synthesis. The hyper-trophic response to bFGF was blocked by anti-TGF-beta. The ability of U46619 and bFGF to increase protein synthesis and protein content in vascular smooth muscle cells was associated with TGF-beta-induced suppression of proliferation, as evidenced by the ability of antibody to TGF-beta to enhance U46619- and bFGF-induced increases in [3H]thymidine incorporation into DNA. Results of the present study also supported a role for protein kinase C in the expression of U46619 and bFGF actions. U46619 increased protein kinase C activity in the particulate fraction of vascular smooth muscle cells. Moreover, the protein kinase C inhibitors GF109203X and staurosporine blocked U46619- and bFGF-induced increases in protein synthesis as well as active and total TGF-beta bioactivities. By contrast, the protein kinase C inhibitors did not prevent the increases in protein synthesis induced by exogenous TGF-beta. The results demonstrate that thromboxane/prostaglandin endoperoxide signals increased TGF-beta bioactivity via protein kinase C. Increases in both bFGF and TGF-beta are required for an optimal hypertrophic response to U46619. The hypertrophic response to TGF-beta occurs through a protein kinase C-independent pathway.