PubMed Health⌕ Search

Biomedical subjects

J E Gern

Publications and source records attributed to J E Gern.

At least 37 records · Page 2Linked to original sources
PubMed1998

Isolation of human conjunctival mast cells and epithelial cells: tumor necrosis factor-alpha from mast cells affects intercellular adhesion molecule 1 expression on epithelial cells.

PURPOSE: To isolate and purify mast cells and epithelial cells from human cadaveric donor conjunctival tissue and to characterize interactions between these cell types in vitro. METHODS: Monodispersed cell suspensions obtained by enzymatic digestion of conjunctival tissue were applied to a single-density Percoll gradient. Epithelial cells obtained from the top layer of the gradient were cultured to confluence. Mast cells obtained from the pellet were equilibrated in culture medium and further purified using a two-step Percoll gradient. Using reverse transcription-polymerase chain reaction (RT-PCR), RNA from the purified mast cell preparation was probed for tumor necrosis factor-alpha (TNF alpha) message. Fluorescence activated cell sorting (FACS) analysis of intracellular immunostained mast cells was used to detect the TNF alpha protein. An examination for intercellular adhesion molecule 1 (ICAM-1) on epithelial cells was performed after 24-hour incubations with either recombinant TNF alpha supernatants from calcium ionophore A23187 (CaI)-stimulated mast cells or appropriate controls using FACS analysis. RESULTS: Highly purified human conjunctival mast cells and epithelial cells (each > 95%) were obtained from human cadaveric donor tissue. RT-PCR analysis of purified mast cell RNA revealed the expression of TNF alpha mRNA. An evaluation of mast cells for intracellular protein demonstrated positive staining for tryptase and TNF alpha. ICAM-1 was found on purified epithelial cells, and incubation of epithelial cell monolayers with supernatants from Cal-stimulated mast cells resulted in upregulation of this receptor. This upregulation was blocked by incubation with TNF alpha-neutralizing antibody. CONCLUSIONS: This work provides the methods for isolating and purifying mast cells and epithelial cells from human donor tissue and the opportunity for studying mechanisms of conjunctival inflammation by evaluating the interactions between these cells.

Calcimycin↗
PubMed1997

The role of respiratory viruses in asthma.

Respiratory infections are common causes of increased asthma for patients of all ages. Current evidence indicates that viral, and not bacterial, infections are the most important respiratory illnesses which increase the severity of asthma. Of the respiratory viral infections associated with increased asthma, rhinoviruses, i.e. the cause of common colds, have proven to be the virus most often found in association with increased asthma severity. Although the association between rhinovirus infections and asthma is most dramatically illustrated in children, asthma patients of all ages can be affected and the attacks of asthma can be severe. Studies to establish the mechanisms by which rhinoviruses enhance asthma severity have begun to focus on how this virus promotes allergic inflammation. We have found that experimental rhinovirus infections enhance airway responsiveness and, perhaps most importantly, the likelihood that a late allergic reaction will occur to an antigen challenge. Furthermore, using bronchoscopy and segmental antigen challenge, we have found that rhinovirus infections promote mast cell release of histamine and the recruitment of eosinophils to the airways. These data support the concept that rhinovirus infections act to promote allergic inflammation and by this mechanism increase both the likelihood of asthma occurring and the severity of wheezing.

Asthma↗
PubMed1997

Rhinovirus-specific T cells recognize both shared and serotype-restricted viral epitopes.

To characterize rhinovirus (RV)-specific T cells, RV16- and RV49-specific CD4 T cells were cloned from peripheral blood, and cytokine secretion and serotype specificity were defined. Each RV-specific clone secreted high levels of interferon-gamma, and several also produced interleukin-4 and -5. To test serotype specificity, each clone was incubated separately with five different RV serotypes. Although 2 of 31 clones proliferated only in response to the virus used in cloning, the rest had significant proliferation in response to 2-5 different serotypes. Thus, RV-specific T cells can be activated by either serotype-specific or shared viral epitopes, raising the possibility that repeated activation of T cells by shared viral determinants in vivo could induce potent recall T cell responses. It is likely that enhanced T cell responses to shared viral epitopes contribute to antiviral activity, airway inflammation, or both.

Antigen-Presenting Cells↗
PubMed1997

Effectiveness of intensive nurse case management in decreasing vertical transmission of human immunodeficiency virus infection in Wisconsin.

BACKGROUND: During a clinical trial (ACTG Study 076), perinatal HIV transmission was reduced by two-thirds when pregnant women with HIV infection and their infants were treated with zidovudine (ZDV). A similar benefit has not been uniformly found in practice settings. OBJECTIVES: To measure the effectiveness of a nurse case management system in supporting prenatal ZDV use in women with HIV infection and their infants and in decreasing perinatal HIV transmission. METHODS: We performed a retrospective cohort study of all children with or at risk for HIV infection cared for in the Wisconsin HIV Primary Care Support Network. The Network uses intensive nurse case management to optimize the care of pregnant women with HIV infection and their children. For children born between January 1, 1992, and April 30, 1996, we measured the association of prenatal case management by a Network nurse with (1) ZDV use by pregnant women with HIV infection and (2) the rate of vertical HIV transmission. RESULTS: In the 26 months after March 1, 1994 (shortly after the release date of ACTG 076 results), 5 of 39 (13%) infants born to women with HIV infection and enrolled in the Network acquired HIV perinatally compared with 12 of 30 (40%) infants in the 26 months preceding March 1, 1994 (P = 0.01). Between March 1, 1994, and April 30, 1996, 25 of 25 (100%) women whose prenatal care included intensive case management by a Network nurse were treated with prenatal orally administered ZDV, compared with 3 of 14 (21%) women whose prenatal care did not include Network case management (P < 0.0001). There were 2 of 25 (8%) infants who acquired HIV infection in the former group, compared with 3 of 14 (21%) in the latter group (P = 0.2) CONCLUSIONS: Perinatal transmission of HIV was significantly decreased following implementation of national recommendations for ZDV treatment of pregnant women. Prenatal care that included case management by a specialized nurse was significantly more likely to result in appropriate ZDV therapy in women and showed a trend toward a lower rate of HIV infection in their infants, compared with prenatal care that did not include such personnel.

Adult↗
PubMed1997

Detection of rhinovirus RNA in lower airway cells during experimentally induced infection.

Rhinovirus (RV) infections are presumed to be localized to the upper airway, yet can cause severe lower airway symptoms in children and adults with asthma. To test the hypothesis that rhinovirus infection of the upper airway may be associated with the presence of virus in lower airway cells, we used the techniques of reverse transcription-polymerase chain reaction (RT-PCR) and Southern blotting to detect RV RNA in lower airway cells from eight allergic volunteers experimentally infected with RV16. Bronchoscopy with bronchoalveolar lavage (BAL) was done 1 mo before, and 2 and 4 d after an experimental infection with RV16. All subjects developed cold symptoms, and infection was confirmed by culturing RV16 from nasal secretions. Rhinovirus RNA was detected in both nasal lavage and lower airway cells from all eight subjects 2 to 4 d after an experimental inoculation, but not in any of the precold specimens from either the nose or the lower airway. These findings suggest that RV can infect cells of the lower airway, and raise the possibility that such an effect can promote asthma exacerbations in the susceptible host through direct enhancement of local inflammation.

Adolescent↗
PubMed1997

Rhinovirus infection preferentially increases lower airway responsiveness in allergic subjects.

Rhinovirus (RV) infections are important triggers of acute asthma symptoms in susceptible persons. To determine whether the presence of allergy is a risk factor for enhanced lower airway effects during RV infection, we experimentally infected (RV16) 18 volunteers with allergic rhinitis and 13 normal control subjects and measured the effects on the response of the lower airways to histamine. All subjects were successfully infected, as indicated by increased upper respiratory symptoms and RV16 cultured from nasal secretions. The change in histamine PD20(deltaPD20) caused by RV infection was significantly different in allergic subjects from that in nonallergic control subjects (deltaPD20 = -0.40 versus -0.03 log units, p = 0.04). This relationship was strengthened after adjusting for initial PD20 and FEV1 (mean deltaPD20 = -0.43 versus 0.01 log units, p < 0.01). The virus-induced deltaPD20 was also influenced by baseline lung function: there was a positive correlation between initial FEV1 and deltaPD20, and a weak but significant negative correlation between baseline PD20 and deltaPD20. These findings indicate that host factors such as allergy, baseline FEV1, and baseline PD20 influence the changes in lower airway physiology caused by RV infection and raise the possibility that these factors contribute to the increased lower airway effects of RV infection in subjects with asthma.

Adult↗
PubMed1996

Rhinovirus produces nonspecific activation of lymphocytes through a monocyte-dependent mechanism.

There is evidence that rhinovirus (RV) infections are frequent causes of increased asthmatic symptoms and can specifically enhance allergic inflammation in the airway. To further define effects of RV infection on cellular immunity, we have begun to develop in vitro models for study. When human PBMC were incubated with 35S-labeled RV16, specific binding via ICAM-1 on monocytes was observed. Incubation of PBMC with RV also led to a dose-related increase in the expression of the early activation marker CD69 on 30 to 70% of T cells. The RV16-induced increases in CD69 were blocked by anti-ICAM-1 mAb, and were not elicited by UV-inactivated (noninfectious) virus. The degree of CD69 enhancement correlated with the number of monocytes in mixtures of PBMC, did not occur in monocyte-depleted cultures, and was mediated by one or more soluble factor(s). RV also induced secretion of IFN-gamma from both peripheral blood T cells and NK cells, and IFN-gamma mRNA was greatest in T cells that were CD69+. Finally, supernatant from RV-activated CD3+CD69+ cells had biologic activity that promoted eosinophil survival in vitro; this RV16-associated activity was blocked when co-incubations were performed with IFN-gamma mAbs. These observations suggest that RV nonspecifically activates a large proportion of T cells through a monocyte-dependent mechanism. Such changes in vivo could enhance airway inflammation, and this may include effects on inflammatory cells in the airways of allergic individuals.

Adult↗
PubMed1996

Rhinovirus enters but does not replicate inside monocytes and airway macrophages.

Potential interactions between rhinovirus (RV) and both the airway macrophage and its precursor cell, the blood monocyte, were investigated in terms of direct binding, intracellular replication, cell survival, and cytokine production. When HeLa cell suspensions are inoculated with RV as a positive control, virus titer increases by 100-fold in the first 24 h, confirming intracellular replication. In contrast, RV titer in monocyte and macrophage suspensions steadily decreased. Despite a lack of productive RV replication, cell-associated RV RNA was detectable using a biotin-labeled cDNA probe as early as 6 h after inoculation. Direct binding of RV16 to macrophages was confirmed using radiolabeled virus, although preincubation with anti-ICAM-1 mAb did not block this interaction. Synthesis of RV RNA, as indicated by [3H]uridine incorporation in actinomycin D-treated cells, was detected in HeLa cells but not macrophages, suggesting that the viral RNA detected inside macrophages was from input virus and was not newly synthesized. RV inoculation did not adversely affect monocyte or macrophage viability. Finally, RV caused macrophage activation, as indicated by the induction of TNF-alpha secretion. These in vitro findings suggest that macrophages interact with major group RV in vivo, and raise the possibility that there is a second cellular receptor for these viruses. Furthermore, macrophages do not serve as permissive host cells during in vivo RV infection, but instead may be active participants in anti-RV immunity and RV-induced airway inflammation.

Antibodies, Monoclonal↗
PubMed1996

Rhinovirus inhibits antigen-specific T cell proliferation through an intercellular adhesion molecule-1-dependent mechanism.

To determine whether binding of human rhinovirus (HRV) to intracellular adhesion molecule-1 might disrupt airway immune processes, effects of a major HRV group, HRV-16, on T cell proliferation and cytotoxicity were defined. HRV (1-10 TCID50/cell) significantly inhibited T cell proliferation induced by antigen but not proliferation secondary to mitogens, interleukin-2, or an irradiated allogeneic T cell line. Noninfectious (UV-irradiated) HRV had similar effects. Inhibition of T cell proliferation was dependent on HRV binding to intercellular adhesion molecule-1 on monocytes, indicating that the virus interferes with lymphocyte activation indirectly through effects on antigen-presenting cells. In addition, HRV inhibited T cell cytotoxic responses but not NK cell activity. If these effects also occur in vivo, the resulting disturbance in local airway immunity could increase the chances of successful viral replication, and might also be a factor in the pathogenesis of secondary viral or bacterial respiratory tract infections.

Antigen Presentation↗
PubMed1995

The effects of rhinovirus infections on allergic airway responses.

Although it has long been recognized that the common cold is a potent trigger for symptoms of asthma, the mechanisms underlying the association between upper respiratory infection and increased lower airway obstruction remain obscure. The use of experimental infection of volunteers with or without respiratory allergies has enabled direct comparisons of common cold symptoms in these two groups. Furthermore, techniques such as bronchoalveolar lavage and segmental antigen challenge have been used to directly sample lower airway fluids and tissues during acute viral infection. This review summarizes the findings of studies examining the separate and combined effects of rhinovirus infection and allergen exposure on airway physiology and inflammation.

Asthma↗
PubMed1995

Childhood asthma. Older children and adolescents.

Asthma is a very significant health problem in children and adolescents, and it is disturbing that this problem is increasing despite recent advances related to asthma pathogenesis and treatment. In this age group, treatment of asthma may be especially challenging because of the need to deal with schools as well as the patient and family, and because of concern for the effects of asthma and asthma therapy on physical and psychological development. Successful asthma therapy in children and adolescents requires close attention to these issues, as well as efforts designed to transfer the responsibility of asthma care from the parent to the adolescent in an age-appropriate fashion.

Adolescent↗
PubMed1994

Peak flow variation in childhood asthma: a three-year analysis.

Measuring peak expiratory flow (PEF) variation has been suggested as a indicator of asthma disease severity and also of nonspecific bronchial hyperreactivity. To test these assumptions, we examined the relationships between PEF variation, methacholine reactivity, symptom scores, and medication requirements in 74 children with tightly controlled allergic asthma. The level of mean diurnal variation (MDV) for the group was 7.1%, which is generally regarded as normal. We found statistically significant correlations between MDV and both methacholine reactivity (r = 0.43, p = 0.0001) and symptom scores (r = 0.28, p = 0.016). These asthma variables were analyzed longitudinally in 33 children who were followed up at 6-month intervals for at least 36 months. Visit-to-visit changes in MDV were generally not reflective of changes in other variables. However, group levels of MDV gradually decreased over time, especially in children with initial MDV of more than 8%. This reduction in group MDV coincided with similar reductions in group medication requirements and methacholine reactivity. We conclude that children with moderately severe asthma that is tightly controlled may have normal levels of PEF variation. The correlation between PEF variation and other asthma variables is statistically significant but too weak to be useful in the treatment of individual patients. In contrast, measurement of MDV may be a useful indicator of disease severity in group studies of asthma.

Asthma↗
PubMed1991

Temperature is a powerful promoter of interleukin 2 transcription.

Elevated temperature has profound effects on the immune system, particularly by increasing T-cell proliferation rates, interleukin 1 (IL-1)-driven secretion of IL-2, and primary antibody responses to T-dependent antigens. Therefore, this study shows, in detail, the effects of incubation temperature (29 degrees C to 41 degrees C) on proliferation, IL-2 secretion, and IL-2 mRNA expression in both a murine thymoma cell line (EL4-6.1) and in nontransformed murine splenocytes. Temperature was found to be a positive regulator of IL-2 secretion whether or not IL-1 was part of the activation signal. Parallel effects were observed at the level of IL-2 gene expression. Messenger RNA was quantitated with a novel system, using solution hybridization followed by detection of RNA-DNA complexes by enzyme immunoassay. The time to onset of IL-2 mRNA expression was inversely related to temperature, and mRNA levels increased 20- to 50-fold with increases in average incubation temperature from 29 degrees C to 39 degrees C. This effect was observed whether cells were incubated at constant temperature or exposed intermittently to elevated temperature. Over the same intervals of time and temperature, mRNA levels for tau-actin and beta-tubulin remained relatively constant. Taken together, these findings suggest that temperature-mediated augmentation of IL-2 secretion does not require the presence of IL-1, and that the effect occurs at a pretranslational level.

Animals↗
PubMed1990

Quantitative detection of messenger RNA by solution hybridization and enzyme immunoassay.

A novel nucleic acid detection technique is described for the quantitative measurement of eukaryotic mRNA in biological samples. The procedure involves two steps: a hybridization reaction in solution with a biotinylated cDNA probe, and a conventional enzyme immunoassay that uses a monoclonal antibody for DNA.RNA hybrids to detect the specific mRNA.cDNA complexes. The method has comparable sensitivity to 32P-based methods and yields results that are quantitative and highly reproducible. Furthermore, the test can be performed using unfractionated cytoplasm without the need for extraction with organic solvents. This technique provides a rapid and quantitative method for studying changes in cellular mRNA levels, and it is suitable for testing large numbers of samples.

Antibodies, Monoclonal↗
PubMed1983

Vesiculopustular eruption of ulcerative colitis.

Many cutaneous disorders that have been described in association with ulcerative colitis (UC), including certain pustular eruptions, probably represent early, evolving lesions of pyoderma gangrenosum (PG). Several nonspecific, often poorly delineated pustular eruptions apparently unrelated to pyoderma gangrenosum have also been reported to occur with ulcerative colitis. A patient had an evanescent, vesiculopustular eruption with a course paralleling that of his UC. Histologic examination of biopsy material from the skin revealed intraepidermal and subcorneal neutrophilic abscess formation and a mixed dermal, perivascular inflammatory cell infiltrate with notable sparing of the follicles. An IgG deposition in a bandlike pattern was identified at the dermoepidermal junction by direct immunofluorescence microscopy. This vesiculopustular eruption may represent a distinct entity or another case or variant of similar pustular eruptions previously described in association with UC.

Adult↗
PubMedDate not supplied

Meperidine attenuates the secretion but not the transcription of interleukin 1 beta in human mononuclear leukocytes.

BACKGROUND: The infusion of amphotericin-B (AmB) often produces clinically distressing rigors and chills, which promptly abate with intravenous injection of meperidine, although its mechanism of action is unknown. OBJECTIVE: To examine the effects of meperidine on the transcription or secretion of Interleukin 1 beta (IL-1 beta) in human mononuclear leukocytes (MNL) exposed in vitro to the lipopolysaccharide (LPS) contained in Escherichia coli endotoxin or to AmB. METHODS: Blood was drawn from eight healthy adult volunteers. The blood was centrifuged, and the layer containing MNL was separated; incubated with various combinations of medium, meperidine, and AmB; then tested for IL-1 content to determine the effect of meperidine on MNL secretion of IL-1 beta. To determine the effect on MNL transcription of IL-1 beta, the RNA was extracted from cells and the IL-1 beta was measured using one of two different methods. RESULTS: Incubation of human MNL in the presence of LPS or AmB significantly increased transcription of IL-1 beta mRNA and secretion of IL-1 beta. Addition of meperidine to these cultures significantly reduced LPS-induced, but not AmB-induced, secretion of IL-1 beta in vitro. Meperidine did not alter IL-1 beta mRNA levels in MNL exposed to LPS or AmB. CONCLUSIONS: These data suggest that meperidine decreases rigors and chills in part by decreasing MNL secretion of IL-1 beta through a posttranscriptional mechanism.

Adult↗