Airborne environmental injuries and human health.

The concept that the environment in which we live can have detrimental effects on our health has existed for centuries. Obvious examples of substances that can cause human diseases include infectious agents, poisons, chemicals and other noxious agents, drugs, and physical stimuli such as bright lights and loud sounds. Some less obvious agents can include allergens, nontangible agents such as colorless, odorless gases and aerosolized toxins. In recent decades, humans have developed various new materials and compounds. Additionally, we are now producing known compounds, and even naturally occurring substances, in vastly increased amounts. Many of these substances are generally believed to threaten the health of our environment. However, there is also a considerable amount of hype and exaggeration regarding some of these agents (e.g., mold) that is unsubstantiated. This article extensively reviews the data on a large number of airborne-related illnesses and attempted to place scientific reality in the context of clinical medicine

Progress in Defining the Role of RSV in Allergy and Asthma: From Clinical Observations to Animal Models

Respiratory syncytial virus (RSV), an RNA virus in the family Paramyxoviridae, causes respiratory disease in humans. A closely related bovine RSV is responsible for a remarkably similar disease syndrome in young cattle. Severe RSV disease is characterized by bronchiolitis. The impact of RSV on human health is demonstrated annually when infants are admitted to the hospital in large numbers. Nearly every child will have been infected with RSV by the age of 3 years. While the disease is most severe in young infants and elderly people, it can re-infect adults causing mild upper respiratory tract disease throughout life. In addition, there is growing evidence that RSV infection may also predispose some children to the development of asthma. This is based on the observation that children who wheeze with RSV-induced bronchiolitis are more likely to develop into allergic asthmatics. Recent studies describe attempts to create an RSV induced asthma model in mice and other species; these have shown some degree of success. Such reports of case studies and animal models have suggested a wide range of factors possibly contributing to RSV induced asthma, these include timing of RSV infection with respect to allergen exposure, prior allergic sensitization, environmental conditions, exposure to endotoxin, and the genetic background of the person or animal. Herein, we primarily focus on the influence of RSV infection and inhalation of extraneous substances (such as allergens or endotoxin) on development of allergic asthma

Analysis of the IDDM Candidate Gene Prss16 in NOD and NON Mice

The thymus-specific serine protease Prss16 is highly expressed by the epithelial cells in the thymic cortex. It has been suggested to play an important role in the positive selection of T cells through the antigen presention pathway of the cortical antigen presenting cells. Recently, the gene ecoding Prss16 has been linked to insulin dependent diabetes mellitus (IDDM) susceptibility independent of HLA-DR3 suggesting the Prss16 may be involved in the development of autoimmune disease. Due to the similarities of the gene structure and expression pattern between the human and mouse genes, we compared Prss16 between non-obese diabetic (NOD) and non-obese non-diabetic (NON) mice. Analysis of the Prss16 coding region failed to identify any differences in sequence. Northern analysis and semi-quantitative reverse transcriptase polymerase chain reaction showed that the mRNA was equal in size and abundance in the two strains. In situ hybridization showed similar patterns of staining. Therefore, our data suggests that there is no significant different in the gene structure, transcription level, and expression pattern of Prss16 gene between NOD and NON mice

Tissue Tropism in Host Transcriptional Response to Members of the Bovine Respiratory Disease Complex.

Bovine respiratory disease (BRD) is the most common infectious disease of beef and dairy cattle and is characterized by a complex infectious etiology that includes a variety of viral and bacterial pathogens. We examined the global changes in mRNA abundance in healthy lung and lung lesions and in the lymphoid tissues bronchial lymph node, retropharyngeal lymph node, nasopharyngeal lymph node and pharyngeal tonsil collected at the peak of clinical disease from beef cattle experimentally challenged with either bovine respiratory syncytial virus, infectious bovine rhinotracheitis, bovine viral diarrhea virus, Mannheimia haemolytica or Mycoplasma bovis. We identified signatures of tissue-specific transcriptional responses indicative of tropism in the coordination of host's immune tissue responses to infection by viral or bacterial infections. Furthermore, our study shows that this tissue tropism in host transcriptional response to BRD pathogens results in the activation of different networks of response genes. The differential crosstalk among genes expressed in lymphoid tissues was predicted to be orchestrated by specific immune genes that act as 'key players' within expression networks. The results of this study serve as a basis for the development of innovative therapeutic strategies and for the selection of cattle with enhanced resistance to BRD

Developmental Considerations of Sperm Protein 17 Gene Expression in Rheumatoid Arthritis Synoviocytes

Rheumatoid arthritis (RA) is an autoimmune disease characterized by proliferative synovial tissue. We used mRNA differential display and library subtraction to compare mRNA expression in RA and osteoarthritis (OA) synoviocytes. We initially compared the mRNA expression patterns in 1 female RA and 1 OA synovia and found a differentially expressed 350 bp transcript in the RA synoviocytes which was, by sequence analysis, 100% homologous to sperm protein 17 (Sp17). Moreover, the Sp17 transcript was found differentially expressed in a RA synovial library that was subtracted with an OA synovial library. Using specific primers for full length Sp17, a 1.1 kb transcript was amplified from the synoviocytes of 7 additional female RA patients, sequenced and found to 100% homologous to Sp17. Thus, we found the unexpected expression of Sp17, a thought to be gamete-specific protein, in the synoviocytes of 8/8 female RA patients in contrast to control OA synoviocytes. Interestingly, Sp17's structural relationship with cell-binding and recognition proteins, suggests that Sp17 may function in cell-cell recognition and signaling in the RA synoviocyte. Further, Sp17 could have a significant regulatory role in RA synoviocyte gene transcription and/or signal transduction. Thus, Sp17 could have an important role in RA synoviocyte proliferation or defective apoptosis. Finally, the presence of Sp17 in synoviocytes has interesting developmental considerations

Phenotypic Characterization of Chicken Thymic Stromal Elements

Phenotypic profiles of the thymic stromal components provide an excellent approach to elucidating the nature of the microenvironment of this organ. To address this issue in chickens, we have produced an extensive panel of 18 mAb to the thymic stroma. These mAb have been extensively characterized with respect to their phenotypic specificities and reveal that the stromal cells are equally as complex as the T cells whose maturation they direct. They further demonstrate that, in comparison to the mammalian thymus, there is a remarkable degree of conservation in thymic architecture between phylogenetically diverse species. Eleven mAb reacted with thymic epithelial cells: MUI-73 was panepithelium, MUI-54 stained all cortical and medullary epithelium but only a minority of the subcapsule, MUI-52 was specific for isolated stellate cortical epithelial cells, MUI-62, -69, and -71 were specific for the medulla (including Hassall’s corpusclelike structures), MUI-51, -53, -70, and -75 reacted only with the type-I epithelium, or discrete regions therein, lining the subcapsular and perivascular regions and MUI-58 demonstrated the antigenic similarity between the subcapsule and the medulla. Seven other mAb identified distinct isolated stromal cells throughout the cortex and medulla. Large thymocyte-rich regions, which often spanned from the outer cortex to medulla, lacked epithelial cells. These mAb should prove invaluable for determining the functional significance of thymic stromal-cell subsets to thymopoiesis

Uterine Mast Cells and Immunoglobulin-E Antibody Responses During Clearance of \u3ci\u3eTritrichomonas foetus\u3c/i\u3e

We showed earlier that Tritrichomonas foetus–specific bovine immunoglobulin (Ig)G1 and IgA antibodies in uterine and vaginal secretions are correlated with clearance of this sexually transmitted infection. Eosinophils have been noted in previous studies of bovine trichomoniasis but the role of mast cells and IgE responses have not been reported. The hypothesis that IgE and mast cell degranulation play a role in clearance was tested in 25 virgin heifers inseminated experimentally and infected intravaginally with T. foetus strain D1 at estrus and cultured weekly. Groups were euthanatized at 3, 6, 9, or 12 weeks, when tissues were fixed and secretions were collected for culture and antibody analysis. Immunohistochemistry using a monoclonal antibody to a soluble lipophosphoglycan (LPG)–containing surface antigen (TF1.17) demonstrated antigen uptake by uterine epithelial cells. Lymphoid nodules were detected below antigen-positive epithelium. Little IgG2 antibody was detected but IgG1, IgA, IgM, and IgE T. foetus–specific antibodies increased in uterine secretions at weeks 6 and 9 after infection. This was inversely proportional to subepithelial mast cells numbers and most animals cleared the infection by the sampling time after the lowest mast cell count. Furthermore, soluble antigen was found in uterine epithelium above inductive sites (lymphoid nodules). Cross-linking of IgE on mast cells by antigen and perhaps LPG triggering appears to have resulted in degranulation. Released cytokines may account for production of predominantly Th2 (IgG1 and IgE) and IgA antibody responses, which are related to clearance of the infection