The magnitude and encephalogenic potential of autoimmune response to MOG is enhanced in MOG deficient mice

Myelin oligodendrocyte glycoprotein (MOG) is a minor component of central nervous system myelin presumably implicated in the pathogenesis of Multiple Sclerosis (MS). Immunization with MOG leads to the development of Experimental Autoimmune Encephalomyelitis (EAE), the experimental model of MS. It has been suggested that its encephalitogenic potential may be due to the lack of MOG self-immune tolerance. To clarify this, we have generated a MOG deficient mouse (MOG(-/-)) strain. Surprisingly, MOG(35-55)specific proliferation and Th1-type cytokine production were markedly enhanced in MOG(-/-)mice compared to wild type control. Furthermore, adoptive transfer of MOG(35-55)specific T cells, isolated from MOG deficient mice, into wild-type recipients resulted in the development of a more severe disease, indicating a high capacity of MOG(-/-)T cells to initiate effector responses. Interestingly, T cell reactivity to overlapping MOG peptides in MOG(-/-)mice did not reveal new potential immunodominant epitopes in H-2(b)mice. Taken together, our data suggests that MOG self-tolerance modulates the encephalitogenic potential of autoreactive MOG T cells in the periphery.     

Effect of an amber mutation in the herpes simplex virus thymidine kinase gene on polypeptide synthesis and stability

KG111 is a mutant of herpes simplex virus (HSV), strain KOS, that exhibits temperature-dependent drug resistance. For example, it is almost as resistant as a thymidine kinase (tk)-deficient virus at 39 degrees, but is relatively sensitive to acyclovir at 34 degrees, Using marker transfer techniques, we have mapped the mutation conferring temperature-dependent drug resistance in KG111 to the 5' portion of the tk gene. Sequencing of this region revealed an amber mutation at codon 44, which lies between the first and second methionine codons of the tk polypeptide. This mutation is identical to that found in TK4, an HSV mutant derived from Cl 101 (L. Haarr et al., 1985, J. Virol. 56, 512-519). Analyses of immunoprecipitated tk proteins from KG111- and TK4-infected cells showed that KG111 and TK4 do not synthesize full-length tk polypeptides, but instead produce a truncated form of the protein. Small amounts of a similar truncated tk polypeptide are also produced in wild-type-infected cells and are thought to arise from initiation at a downstream AUG. The relative amounts and size of the mutant tk proteins compared with those of the wild-type are consistent with the amber mutation eliminating translation of full-length polypeptide and causing a four- to fivefold increase in the utilization of downstream AUG codons for initiation. The truncated polypeptides specified by KG111 and TK4 are less stable than the full-length polypeptide at 39 degrees, which may contribute to the conditional drug-resistant phenotype. On the other hand, the truncated polypeptides normally expressed by wild-type virus at low levels and the more highly expressed truncated tk polypeptides from a deletion mutant are relatively stable at 39 degrees. These results suggest that stability of the truncated tk polypeptide is influenced by the amount of tk present.     

Skin ligaments: regional distribution and variation in morphology

Skin ligaments (SL) (L. retinacula cutis) are present extensively in the face, hands, feet, and in breast tissue, but have seldom been reported elsewhere in the body. The traditional histological view of the subcutaneous region is that it comprises a matrix of loose connective tissue devoid of fibrous specializations. The purpose of this study was to determine the structure and distribution of skin ligaments. Eight embalmed cadavers (3 males, 5 females, 69-90 years of age) were used in this study. Tissue was prepared using the E12 plastination technique. Macroscopic and microscopic examination demonstrated the widespread presence in the limbs and most of the rest of the body of fibrous strands linking the base of the dermis and the superficial fibers of the underlying deep fascia. The morphology and distribution of these skin ligaments were similar in the individuals examined. Variations in the structure of the skin ligaments depended on the presence of underlying muscle, neurovascular bundles, intermuscular septa and adipose tissue. We conclude that skin ligaments are complex fibrous structures that are present over most of the body. They form an extensive peripheral network in the subcutaneous fat. These 'ligaments' seem to provide an anchorage of skin to deep fascia that is flexible and yet resistant to mechanical loading from multi-directional forces. The use of the E12 plastination technique coupled with fluorescent confocal microscopy has been of benefit in visualizing and delineating SLs from other soft tissue structures in three planes.     

Transforming growth factor-beta induces loss of epithelial character and smooth muscle cell differentiation in epicardial cells.

During embryogenesis, epicardial cells undergo epithelial-mesenchymal transformation (EMT), invade the myocardium, and differentiate into components of the coronary vasculature, including smooth muscle cells. We tested the hypothesis that transforming growth factor-beta (TGFbeta) stimulates EMT and smooth muscle differentiation of epicardial cells. In epicardial explants, TGFbeta1 and TGFbeta2 induce loss of epithelial morphology, cytokeratin, and membrane-associated Zonula Occludens-1 and increase the smooth muscle markers calponin and caldesmon. Inhibition of activin receptor-like kinase (ALK) 5 blocks these effects, whereas constitutively active (ca) ALK5 increases cell invasion by 42%. Overexpression of Smad 3 did not mimic the effects of caALK5. Inhibition of p160 rho kinase or p38 MAP kinase prevented the loss of epithelial morphology in response to TGFbeta, whereas only inhibition of p160 rho kinase blocked TGFbeta-stimulated caldesmon expression. These data demonstrate that TGFbeta stimulates loss of epithelial character and smooth muscle differentiation in epicardial cells by means of a mechanism that requires ALK5 and p160 rho kinase.     

Proposed criteria for mixed-dust pneumoconiosis: definition, descriptions, and guidelines for pathologic diagnosis and clinical correlation

We defined mixed-dust pneumoconiosis (MDP) pathologically as a pneumoconiosis showing dust macules or mixed-dust fibrotic nodules (MDF), with or without silicotic nodules (SN), in an individual with a history of exposure to mixed dust. We defined the latter arbitrarily as a mixture of crystalline silica and nonfibrous silicates. According to our definition of MDP, therefore, MDF should outnumber SN in the lung to make a pathologic diagnosis of MDP. In the absence of confirmation of exposure, mineralogic analyses can be used to support the pathologic diagnosis. The clinical diagnosis of MDP requires the exclusion of other well-defined pneumoconioses, including asbestosis, coal workers’ pneumoconiosis, silicosis, hematite miners’ pneumoconiosis, welders’ pneumoconiosis, berylliosis, hard metal disease, silicate pneumoconiosis, diatomaceous earth pneumoconiosis, carborundum pneumoconiosis, and corundum pneumoconiosis. Typical occupations associated with the diagnosis of MDP include metal miners, quarry workers, foundry workers, pottery and ceramics workers, and stonemasons. Irregular opacities are the major radiographic findings in MDP (ILO 1980), in contrast to silicosis, in which small rounded opacities predominate. Clinical symptoms of MDP are nonspecific. MDP must be distinguished from a variety of nonoccupational interstitial pulmonary disorders.     

Serological heterogeneity of the IgM components of mixed (monoclonal IgM–polyclonal IgG) cryoglobulins

Mixed IgG–IgM cryoglobulins were isolated from the sera of seven patients with macroglobulinaemia or cryoglobulinaemia. The IgM components of all seven cryoproteins were monoclonal, containing κ light chains only, whereas the IgG components were polyclonal, containing both κ and λ light chains. Despite their apparent immunological homogeneity, the IgM components showed a wide range of antiglobulin activity. The data indicate that serological specificity may vary from one mixed cryoglobulin to another and that the monoclonal IgM components of different mixed cryoglobulins represent a heterologous group of antiglobulins.     

Completeness of reporting on prognostic factors for breast cancer: a regional survey.

BACKGROUND: Effective management of breast cancer is dependent on adequate pathological reporting of the surgical specimen. OBJECTIVE: To describe the frequency with which histopathological features of known prognostic importance are routinely recorded. STUDY POPULATION: 885 cases of invasive breast cancer diagnosed in NHS laboratories in Lancashire and Greater Manchester. METHODS: Pathology reports were reviewed for details for tumour histological type, size, and grade, the presence or absence of tumour in blood or lymphatic vascular channels, and a comment on the proximity of tumour to the lines of surgical excision. Laboratories were categorised according to their throughput of cases of breast cancer, involvement in the breast screening programme, and whether they were attached to a teaching hospital. RESULTS: Histological type, tumour size, presence or absence of tumour in vascular channels, and adequacy of excision were recorded for 843 (95%), 803 (91%), 436 (49%), and 761 (86%) cases, respectively. Non-screening and low throughput laboratories were significantly less likely to record certain histopathological features. No significant differences were observed between teaching and non-teaching hospitals. CONCLUSIONS: The substantial interlaboratory variation in the histopathological reporting of breast cancers can, in part, be related to throughput of cases and involvement in the breast screening programme.     

Precipitating antibodies to DNA induced by heat-denatured DNA-albumin conjugates in the rabbit

(1) Antibodies reactive with purified DNA in the complement fixation system and induced by active immunization of rabbits with methylated bovine serum albumin—DNA aggregate (MBSA—DNA) have been previously described. The present study demonstrates their reactivity in the quantitative and double diffusion preciptin systems. In these systems they have shown preferential reactivity with heat denatured DNA and great cross-reactivity with denatured DNA from various sources.

(2) Methylated rabbit serum albumin—DNA aggregate (MRSA—DNA) is an effective immunizing antigen resulting in the production of antibodies similar to those produced by MBSA—DNA.

(3) The precipitating antibodies in this system are 19S immunoglobulins and appear to be identical to the complement fixing antibodies.

(4) The precipitin reaction is not significantly inhibited by mono-nucleotides.

     

Effect of enzymes on rotavirus infectivity.

The infectivity of a bovine rotavirus was enhanced 140-, 8-, and 3-fold, respectively, by trypsin, protease, and lactase. Ficin, carboxypeptidases A and B, lysozyme, and beta-galactosidase had little effect on the infectivity. Chymotrypsin caused a threefold decrease in the infectivity. Trypsin acts directly on the rotavirus and not on the host cell.     

Evaluation of fluorescent antinuclear antibody assays, Crithidia luciliae substrate, and single-stranded DNA-binding capacity in diagnosis of four rheumatic diseases.

Sera from groups of patient with systemic lupus erythematosus, mixed connective tissue disease, rheumatoid arthritis, and progressive systemic sclerosis and normal controls were compared, using different antinuclear antibody assays. Hep-II cells, used as a substrate for the detection of antinuclear antibodies, appeared to be more sensitive than rat liver substrate. In addition, the fluorescent patterns were easier to identify on Hep-II cells. All systemic lupus erythematosus sera with antibodies reactive with kinetoplasts of Crithidia luciliae had binding greater than 43% for single-stranded DNA. Based on the high sensitivity of the Hep-II substrate and the relative specificity of high (greater than 43%) binding for single stranded DNA by sera from patients with systemic lupus erythematosus, it appears that these two tests are most useful in differential diagnosis and for the detection of systemic lupus erythematosus.