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Biomedical subjects

T R Martin

Publications and source records attributed to T R Martin.

At least 55 records · Page 3Linked to original sources
PubMed1998

Epicutaneous sensitization with protein antigen induces localized allergic dermatitis and hyperresponsiveness to methacholine after single exposure to aerosolized antigen in mice.

Our understanding of the pathogenesis of atopic dermatitis (AD) and its relationship to asthma remains incomplete. Herein, we describe a murine model of epicutaneous (EC) sensitization to the protein allergen, chicken egg albumin, ovalbumin (OVA), which results in a rise in total and OVA-specific serum IgE and leads to the development of a dermatitis characterized by infiltration of CD3(+) T cells, eosinophils, and neutrophils and by local expression of mRNA for the cytokines IL-4, IL-5, and interferon-gamma. A single exposure of the EC sensitized mice to aerosolized OVA induced eosinophilia in the bronchoalveolar lavage fluid and airway hyperresponsiveness to intravenous methacholine as assessed by measurement of pulmonary dynamic compliance (Cdyn). These results suggest a possible role for EC exposure to antigen in atopic dermatitis and in the development of allergic asthma.

Administration, Cutaneous↗
PubMed1998

Rapid fluorescence-based measurement of neutrophil migration in vitro.

We have standardized a new chemotaxis chamber that uses fluorescence as the cellular marker for the measurement of leukocyte migration in vitro in disposable 96-well microplates. This new fluorescence-based assay is a robust assay because filter pore size, cell density, filter composition, and filter thickness do not affect PMN migration towards interleukin-8 or the complement fragment, C5a. When compared to two separate chemotaxis assays in which the migrated cells are counted visually, the fluorescence-based assay was more rapid, less labor intensive, and more sensitive. This new assay is a significant advance in the measurement of leukocyte migration in vitro.

Cell Count↗
PubMed1998

Quantitative comparison of C-X-C chemokines produced by endotoxin-stimulated human alveolar macrophages.

The C-X-C chemokines are a structurally related and functionally redundant family of proteins with neutrophil chemotactic activity. Many of the C-X-C chemokines are produced by endotoxin-stimulated alveolar macrophages (AMs), but knowledge of their relative quantities and their relative contributions to the total chemotactic activity released from these cells is incomplete. Human AMs were stimulated with or without Escherichia coli endotoxin for 2, 4, 8, and 24 h. The mRNA sequences of interleukin (IL)-8, the 78-amino acid epithelial cell-derived neutrophil activator (ENA-78), growth-related protein (GRO) alpha, GRObeta, and GROgamma were cloned by PCR and identified by sequence analysis. The relative mRNA quantities were compared by Northern analysis, and IL-8 was found to predominate. Similarly, IL-8 protein concentrations in the cell supernatants were consistently higher than either the ENA-78 or GRO concentration, and by 24 h, IL-8 concentrations were 10-fold higher than those of the other C-X-C chemokines. Blocking polyclonal antibodies to IL-8 substantially reduced the chemotactic activity in the AM supernatants, whereas antibodies to ENA-78 and GRO had little or no effect. We conclude that IL-8 is the predominant C-X-C chemokine and the dominant neutrophil chemoattractant accumulating in 24-h supernatants of lipopolysaccharide-stimulated human AMs. These studies provide insight into potentially effective strategies of interrupting AM-derived inflammatory signals in the lungs.

Amino Acid Sequence↗
PubMed1998

Elevated transforming growth factor-alpha levels in bronchoalveolar lavage fluid of patients with acute respiratory distress syndrome.

The acute respiratory distress syndrome (ARDS) frequently results in a fibroproliferative response that precludes effective alveolar repair. Transforming growth factor-alpha (TGF-alpha), a potent epithelial and mesenchymal cell mitogen, may modulate the response to lung injury. In this study, we determined whether bronchoalveolar lavage fluid (BALF) concentrations of TGF-alpha are increased during the first 2 wk after the onset of ARDS and, if so, whether increased TGF-alpha levels in lavage fluid are associated with increased levels of procollagen peptide III (PCP III), a biological marker of fibroproliferation, and with increased fatality rates. We enrolled 74 consecutive patients with ARDS prospectively identified on admission to the intensive care unit of a tertiary care hospital, and 11 patients with chronic interstitial lung disease. Thirteen healthy volunteers served as control subjects. TGF-alpha concentrations were measured in BALF recovered on Days 3, 7, and 14 after the onset of ARDS (total of 130 lavage samples). TGF-alpha was detected in the lavage fluid of 90% of patients with ARDS (67 of 74), and in 100% of patients with idiopathic pulmonary fibrosis (IPF) (10 of 10), but in none of 13 normal volunteers. At each day tested, the median lavage TGF-alpha level of patients with ARDS was significantly higher than that of normals. The overall fatality rate was 45% (33 of 74 patients). In a univariate analysis, the median TGF-alpha levels in nonsurvivors were 1.5-fold higher at Day 7 (p = 0.06) and 1.8-fold higher at Day 14 (p = 0.048). The fatality rate was 4 times higher (CI 1.6, 17.5) for patients with both increased lavage TGF-alpha and PCP III concentrations at Day 7 than for patients with low TGF-alpha and PCP III values, indicating a synergistic relationship between TGF-alpha and PCP III. We conclude that increased levels of TGF-alpha in BALF are common in patients with ARDS and that lavage TGF-alpha is associated with a marker of the fibroproliferative response in sustained ARDS.

Adolescent↗
PubMed1998

Clinical application of the Mycobacterium tuberculosis direct test: case report, literature review, and proposed clinical algorithm.

The relatively new Mycobacterium tuberculosis direct test (MTDT) enzymatically amplifies M tuberculosis complex 16s ribosomal RNA. The sensitivity of the test ranges from 75 to 100%, with specificity of 95 to 100%, positive predictive value between 78% and 100%, and negative predictive value between 95% and 100%. Similar test characteristics have been documented in nonrespiratory specimens and in specimens that ultimately grow nontuberculous mycobacterium (NTM). This test allows for rapid identification of M tuberculosis in the smear-positive patient and may greatly improve sensitivity over acid-fast bacilli smear alone. A negative test result with a positive smear suggests infection with NTM or Mycobacterium avium complex. We present a case that illustrates the value of MTDT for analysis of tissue specimens in immunocompromised patients with suspected mycobacterial disease and review the rapidly developing literature about this test. We propose an algorithm using MTDT, acid-fast smear, and mycobacterial culture for the diagnosis and treatment of the immunocompromised patient with suspected mycobacterial infection.

Adult↗
PubMed1997

Increased phagocyte Fc gammaRI expression and improved Fc gamma-receptor-mediated phagocytosis after in vivo recombinant human interferon-gamma treatment of normal human subjects.

Recombinant human interferon-gamma (rhIFN-gamma) decreases the frequency of serious infections in patients with chronic granulomatous disease (CGD) through an unknown mechanism. To test the hypothesis that it exerts a beneficial effect by enhancing clearance of microbes from the bloodstream and tissues, normal human subjects were treated in vivo with rhIFN-gamma. Phagocyte opsonic receptor expression, serum opsonin levels, and phagocytosis of bacteria were then measured. A 4.7-fold increase in neutrophil expression of the high-affinity Fc gamma-receptor (Fc gammaRI) was observed that peaked 48 hours after the initiation of rhIFN-gamma treatment (P < .05). Monocyte expression of Fc gammaRI, Fc gammaRII, Fc gammaRIII, CD11a, CD11b, CD18, and HLA-DR also significantly increased with peak expression at 48 hours. Phagocytosis by neutrophils of killed Staphylococcus aureus opsonized with heat-inactivated pooled human serum significantly improved after rhIFN-gamma treatment (P < .05) and correlated with Fc gammaRI expression by neutrophils (r = .8, P < .001). This increase in ingestion could be inhibited by anti-Fc gammaRI monoclonal antibodies. Levels of the serum opsonin lipopolysaccharide-binding protein also significantly increased after in vivo rhIFN-gamma (P < .05). These results suggest that the protective effect of rhIFN-gamma in patients with CGD may involve improved microbial clearance. Moreover, improved phagocyte trafficking may occur secondary to increased expression of monocyte beta2-integrins. Because these IFN-gamma-related improvements in host defense were seen in normal hosts, rhIFN-gamma may have broader applications in the treatment of various disorders of immunity in addition to its demonstrated efficacy in CGD.

Acute-Phase Proteins↗
PubMed1997

A sensitive immunoassay to detect the alpha-chemokine GRO in rabbit blood and lung fluids.

GRO-alpha, GRO-beta and GRO-gamma are closely related peptides that stimulate growth of tumor cells and activate leukocytes in acute inflammatory reactions. In order to study the biology of GRO peptides in the lungs of experimental animals, we have developed and characterized a sensitive and specific immunoassay for rabbit GRO, and used this assay to measure GRO in rabbit lung fluids and plasma. GRO was cloned from a rabbit cDNA library and expressed in Escherichia coli. Specific goat polyclonal antibodies were used to create an antigen-capture immunoassay. The assay is sensitive to approximately 30 pg/ml GRO and does not crossreact with rabbit IL-8 or MCP-1, or human GRO. The assay accurately measures GRO in rabbit bronchoalveolar lavage fluid, plasma and serum. Rabbit erythrocytes bind little GRO and do not interfere with the detection of GRO in lung fluids. Circulating GRO was detected in the plasma of 4 of 6 pathogen-free rabbits, but the function of circulating GRO in normal animals is uncertain. This immunoassay will facilitate the study of the biology of GRO in rabbits with acute and chronic inflammation in the lungs and other tissues.

Animals↗
PubMed1997

Suppression of herpes simplex virus type 1 (HSV-1)-induced pneumonia in mice by inhibition of inducible nitric oxide synthase (iNOS, NOS2).

Intranasal Herpes simplex virus type 1 (HSV-1) infection of mice caused pneumonia. Manifestations of the disease included: histological pneumonitis, pulmonary influx of lymphocytes, decreased pulmonary compliance, and decreased survival. Immunohistochemical staining demonstrated iNOS induction and the nitrotyrosine antigen in the lungs of infected, but not uninfected mice, suggesting that nitric oxide contributes to the development of pneumonia. To elucidate the role of nitric oxide in the pathogenesis of HSV-1 pneumonia, infected mice were treated either with the inhibitor of nitric oxide synthase activity, N(G)-monomethyl-L-arginine (L-NMMA), or, as a control, with PBS or D-NMMA. L-NMMA treatment decreased the histological evidence of pneumonia and reduced the bronchoalveolar lavage lymphocyte number to one-quarter of the total measured in control-treated mice. L-NMMA treatment significantly improved survival and pulmonary compliance of HSV-1-infected mice. Strikingly, the L-NMMA-mediated suppression of pneumonia occurred despite the presence of a 17-fold higher pulmonary viral titer. Taken together, these data demonstrated a previously unrecognized role of nitric oxide in HSV-1-induced pneumonia. Of note, suppression of pneumonia occurred despite higher pulmonary virus content; therefore, our data suggest that HSV-1 pneumonia is due to aspects of the inflammatory response rather than to direct viral cytopathic effects.

Animals↗
PubMed1997

Systemic anaphylaxis in the mouse can be mediated largely through IgG1 and Fc gammaRIII. Assessment of the cardiopulmonary changes, mast cell degranulation, and death associated with active or IgE- or IgG1-dependent passive anaphylaxis.

We attempted to elicit active anaphylaxis to ovalbumin, or passive IgE- or IgG1-dependent anaphylaxis, in mice lacking either the Fc epsilonRI alpha chain or the FcR gamma chain common to Fc epsilonRI and Fc gammaRI/III, or in mice lacking mast cells (KitW/ KitW-v mice), and compared the responses to those in the corresponding wild-type mice. We found that the FcR gamma chain is required for the death, as well as for most of the pathophysiological changes, associated with active anaphylaxis or IgE- or IgG1-dependent passive anaphylaxis. Moreover, some of the physiological changes associated with either active, or IgG1-dependent passive, anaphylactic responses were significantly greater in Fc epsilonRI alpha chain -/- mice than in the corresponding normal mice. Finally, while both KitW/KitW-v and congenic +/+ mice exhibited fatal active anaphylaxis, mast cell-deficient mice exhibited weaker physiological responses than the corresponding wild-type mice in both active and IgG1-dependent passive systemic anaphylaxis. Our findings strongly suggest that while IgE antibodies and Fc epsilonRI may influence the intensity and/or kinetics of some of the pathophysiological changes associated with active anaphylaxis in the mouse, the mortality associated with this response can be mediated largely by IgG1 antibodies and Fc gammaRIII.

Anaphylaxis↗
PubMed1997

Allergen-induced bronchial hyperreactivity and eosinophilic inflammation occur in the absence of IgE in a mouse model of asthma.

In patients with asthma, elevations of IgE correlate both with allergic inflammation of the airways and with bronchial hyperreactivity (BHR). Several investigations, using mouse models of this disease, have indicated a central role for IgE in the pathogenesis of the eosinophilic inflammation as well as in the obstructive airway physiology of BHR. Some diagnostic studies and therapeutic strategies for asthma are based on the putative role of IgE in asthma pathogenesis. Here, we use mice with a null mutation of the C epsilon locus to show that bronchial inflammation and BHR in response to allergen inhalation both can occur in the absence of IgE. We demonstrate that the eosinophilic bronchial inflammation elicited in an established mouse model of hypersensitivity to Aspergillus fumigatus (Af) is accompanied by the asthmatic physiology of BHR. Wild-type and IgE-deficient mice were sensitized intranasally with Af extract. Both groups of animals developed bronchoalveolar lavage eosinophilia and pulmonary parenchymal eosinophilia. This was accompanied by increased serum levels of total and Af-specific IgE in the wild-type animals only. This Af-sensitization protocol resulted in significant BHR in both wild-type mice and IgE-deficient mice. Interestingly, unsensitized IgE-deficient mice had increased bronchial responsiveness compared with unsensitized wild-type controls. We conclude that BHR and airways inflammation can be fully expressed via IgE-independent mechanisms. These may involve the activation of mast cells by factors other than IgE as well as a mucosal lymphocyte-mediated immune response to allergen.

Allergens↗
PubMed1997

Studies on the interaction of IL-8 with human plasma alpha 2-macroglobulin: evidence for the presence of IL-8 complexed to alpha 2-macroglobulin in lung fluids of patients with adult respiratory distress syndrome.

alpha 2-Macroglobulin (alpha 2m) is a major plasma proteinase inhibitor, as well as a carrier and regulator of the function of many cytokines. IL-8 is a potent neutrophil attractant and activator, and it plays an important role in the pathogenesis of adult respiratory distress syndrome (ARDS). The concentration of both IL-8 and alpha 2m is increased in lung fluids from patients with ARDS. Therefore, interaction of IL-8 with human alpha 2m was studied. Mixtures of native and methylamine-treated alpha 2m (fast alpha 2m) with 125I-labeled IL-8 were analyzed using nonreducing gel electrophoresis. 125I-labeled IL-8 exclusively bound to fast alpha 2m, and the binding could be inhibited by unlabeled IL-8. Analysis of the IL-8-alpha 2m interaction using SDS-PAGE gels indicated that the binding was mainly noncovalent. The affinity of the binding of alpha 2m to IL-8 was measured using an equilibrium dialysis technique, and Kd was 30 nM. Bioassays revealed that fast alpha 2m did not affect IL-8-induced neutrophil degranulation or chemotaxis. However, it protected IL-8 from proteolytic degradation. In addition, IL-8 complexed to alpha 2m was detected in lung fluids from patients with ARDS. alpha 2m may therefore modulate IL-8 function in the lung.

Antigens, CD↗
PubMed1997

Lipopolysaccharide binding protein and soluble CD14 receptor protein in amniotic fluid and cord blood in patients at term.

OBJECTIVES: Our purpose was to examine whether lipopolysaccharide binding protein and soluble CD14 are present in amniotic fluid and to determine whether the lipopolysaccharide binding protein and soluble CD14 concentrations are associated with indicators of infection or labor at term. A lipopolysaccharide-lipopolysaccharide binding protein complex activates macrophages through soluble CD14 at lipopolysaccharide concentrations up to 100 times lower than required with lipopolysaccharide alone. Thus lipopolysaccharide binding protein and soluble CD14 in amniotic fluid could explain the high concentrations of cytokines found in amniotic fluid of culture-positive patients and may even explain the presence of cytokines in some culture-negative patients. STUDY DESIGN: Healthy women at term undergoing cesarean section had amniotic fluid, chorioamnion, decidua, and cord blood obtained. Lipopolysaccharide binding protein was measured by enzyme-linked immunosorbent assay. Amniotic fluid was cultured and assayed for cytokines, and the chorioamnion and decidua were cultured and examined histologically. RESULTS: Lipopolysaccharide binding protein and soluble CD14 were present in all amniotic fluids and fetal cord blood. An elevated level of lipopolysaccharide binding protein (270 ng/ml/mg of protein) was present in the amniotic fluid of 12 (36%) of the 33 patients. An elevated level was associated with microorganisms in the chorioamnion and decidua, cytokines (tumor necrosis factor-alpha, interleukin-6, and interleukin-8) in amniotic fluid, histologic chorioamnionitis, and labor. Among patients in labor, the concentration of lipopolysaccharide binding protein appeared independent of microorganisms in the amniotic fluid. CONCLUSIONS: Lipopolysaccharide binding protein and soluble CD14 are present in amniotic fluid, and concentrations of lipopolysaccharide binding protein are elevated in patients in labor with and without evidence of infection. Lipopolysaccharide binding protein and soluble CD14 may mediate intrauterine inflammatory responses at term.

Acute-Phase Proteins↗
PubMed1997

A wheezy infant unresponsive to bronchodilators.

When infants with recurrent wheezing have a clinical course inconsistent with asthma, an extensive list of alternative diagnoses needs to be considered. Anatomic malformations, such as congenital heart disease, laryngotracheomalacia, and diaphragmatic hernia, should be considered for immediate medical stabilization and early surgical correction. Life-threatening infections such as bacterial epiglottitis, retropharyngeal cellulitis, and viral myocarditis require prompt intervention. A careful history and physical examination reveal important diagnostic clues that, in this case, prompted a directed evaluation to rule out common masqueraders of asthma such as foreign body aspiration, cystic fibrosis, gastroesophageal reflux, viral pneumonitis, or pulmonary tuberculosis. On occasion, such a search is unrevealing and a diagnostic challenge remains. In those situations, judicious use of modern technology to scrutinize anatomic (high-resolution computed tomography) and functional (infant pulmonary function tests) pathology, and justifiable invasive procedures such as bronchoscopy and lung biopsy, uncover the true diagnosis, allowing for optimal management.

Asthma↗
PubMed1997

T-lymphocytes regulate genetically determined airway hyperresponsiveness in mice.

Airway hyperresponsiveness (AHR) is a hallmark of asthma and a heritable polygenic trait in the mouse. In the mouse, candidate gene products of hematopoietic origin implicated in asthma mapped to the regions of the previously defined quantitative trait loci. Since hematopoietic cells have been implicated in the pathogenesis of asthma, we evaluated the role of hematopoietic cells in general and T cells specifically in the genetic modulation of native airway responsiveness in mice. Here, with the use of bone marrow transplantation, anti-T-cell monoclonal antibody treatment and T-cell transfer, we demonstrate that intrinsic non-atopic AHR is mediated by T lymphocytes. Our data support the novel concept that, in the absence of identified environmental influences, T cells enhance genetically determined airway responsiveness.

Adoptive Transfer↗
PubMed1997

Persistence of pulmonary pathology and abnormal lung function in IL-3/GM-CSF/IL-5 beta c receptor-deficient mice despite correction of alveolar proteinosis after BMT.

Mice deficient for the IL-3/GM-CSF/IL-5 beta c receptor (beta cR KO) develop lung disease similar to that seen in human pulmonary alveolar proteinosis (PAP) which includes lymphocytic infiltration around airways and vessels and the progressive accumulation of surfactant and macrophages within the alveolar space. We investigated bone marrow transplantation (BMT) as a curative treatment of PAP in beta cR KO mice by semiquantitative histologic analysis and evaluation of pulmonary function. BMT from wild-type (WT) donors into lethally irradiated beta cR KO recipients (WT --> KO) led to the complete resolution of alveolar protein accumulation and to normalization of BAL fluid cellularity and macrophage morphology. However, detailed microscopic analysis of lung tissue revealed the persistence of significant cellular infiltrates in WT --> KO recipients which were equivalent to those seen in KO --> KO animals. Evaluation of pulmonary function demonstrated that only dynamic compliance (Cdyn) and not airway conductance (G[L]) was significantly improved in the WT --> KO group compared to KO --> KO animals and that both of these measurements remained significantly abnormal when compared to WT --> WT controls. We conclude, that although BMT for PAP reverses alveolar macrophage and protein accumulation, it does not decrease the interstitial inflammatory component of this disease. The importance of this residual pathology is demonstrated by the incomplete correction of alveolar function (Cdyn) and lack of improvement in increased airway resistance (G[L]). These findings may have important implications with regard to the extent that BMT can be considered a potential curative procedure for this clinical disorder.

Animals↗
PubMed1997

Management of giant paraesophageal hernia.

A retrospective review was performed of 51 patients operated on for giant paraesophageal hiatal hernia to compare the transthoracic and transabdominal approaches and to assess the value of a concomitant fundoplication. Operative repair was performed using open transthoracic, transabdominal, and thoracoabdominal approaches. Laparoscopic techniques were used in one patient. Fundoplication was performed in 45 patients. There was no operative mortality, but early postoperative complications occurred in 29% of patients. The presence of commonly associated symptoms was used to derive preoperative and postoperative symptom scores. Follow-up was available in 48 patients. Excellent results were reported in 69% of patients and 17% had good results. The symptom score improved significantly regardless of the operative approach selected or whether a fundoplication was performed. We conclude that outcome after open paraesophageal hiatal hernia repair is satisfactory in most patients, irrespective of the route chosen or techniques used for repair.

Abdomen↗