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S R Kleeberger

Publications and source records attributed to S R Kleeberger.

At least 19 recordsLinked to original sources
PubMed1999

Ozone-induced pulmonary inflammation and epithelial proliferation are partially mediated by PAF.

Ozone (O3) exposure stimulates airway inflammation and epithelial sloughing in a number of species, including mice. Platelet-activating factor (PAF) is a lipid mediator released by activated mast cells, macrophages, and epithelial cells and causes pulmonary inflammation and hyperpermeability. We hypothesized that the activation of PAF receptors is central to the development of inflammation and epithelial injury induced by acute O3 exposure in mice. To test this hypothesis, O3-susceptible C57BL/6J mice were treated with a PAF-receptor antagonist, UK-74505, or vehicle either before or immediately after 3-h exposure to O3 (2 parts/million) or filtered air. Bronchoalveolar lavage (BAL) fluids were collected 6 and 24 h after exposure. Differential cell counts and protein content of the lavage were used as indicators of inflammation in the airways. O3-induced epithelial injury was assessed by light microscopy, and DNA synthesis in epithelium of terminal bronchioles was estimated by using a bromodeoxyuridine-labeling index. Intercellular adhesion molecule 1 (ICAM-1) expression was also examined in the lung by immunohistochemical localization. O3 caused significant increases in polymorphonuclear leukocytes and protein in the BAL fluid, increased pulmonary epithelial proliferation, and increased epithelial expression of ICAM-1 compared with air-exposed, vehicle-treated control mice. Relative to O3-exposed, vehicle-treated control mice, UK-74505 before exposure significantly (P < 0.05) decreased BAL protein, polymorphonuclear leukocytes, and epithelial cells. O3-induced inflammation was similarly attenuated in mice treated with UK-74505 after exposure. These experiments thus support the hypothesis that O3-induced airways inflammation and epithelial damage in mice are partially mediated by activation of PAF receptors, possibly through modulation of ICAM-1 expression.

Animals↗
PubMed1997

Interleukin 9: a candidate gene for asthma.

Asthma is a complex heritable inflammatory disorder of the airways associated with clinical signs of atopy and bronchial hyperresponsiveness. Recent studies localized a major gene for asthma to chromosome 5q31-q33 in humans. Thus, this segment of the genome represents a candidate region for genes that determine susceptibility to bronchial hyperresponsiveness and atopy in animal models. Homologs of candidate genes on human chromosome 5q31-q33 are found in four regions in the mouse genome, two on chromosome 18, and one each on chromosomes 11 and 13. We assessed bronchial responsiveness as a quantitative trait in mice and found it linked to chromosome 13. Interleukin 9 (IL-9) is located in the linked region and was analyzed as a gene candidate. The expression of IL-9 was markedly reduced in bronchial hyporesponsive mice, and the level of expression was determined by sequences within the qualitative trait locus (QTL). These data suggest a role for IL-9 in the complex pathogenesis of bronchial hyperresponsiveness as a risk factor for asthma.

Animals↗
PubMed1997

Linkage analysis of susceptibility to ozone-induced lung inflammation in inbred mice.

Exposures to the common air pollutant ozone (O3) cause decrements in pulmonary function and induce airway inflammation that is characterized by infiltration of polymorphonuclear neutrophils (PMNs; refs 1-4). Because of the impact that O3 may have on public health, it is critical to identify susceptibility factors. Highly reproducible, significant inter-individual variations in human pulmonary function responses to O3 support the hypothesis that genetic background is an important determinant. Initial analysis of PMN responses to O3 exposure in segregant populations derived from inflammation-prone (susceptible) C57BL/6J (B6) and inflammation-resistant C3H/HeJ (C3) inbred mice indicated that susceptibility was controlled by a locus we termed Inf2 (ref. 7). Subsequent analyses with recombinant inbred strains suggested that a more complex interaction of genes is involved. In this report, we identify a quantitative trait locus (QTL) for O3 susceptibility on chromosome 17. Candidate genes for the locus include Tnf, the gene encoding the pro-inflammatory cytokine tumour necrosis factor-alpha (Tnf). Antibody neutralization of the protein product of this putative candidate gene significantly protected against O3 injury in susceptible mice. These results strongly support linkage of O3 susceptibility to a QTL on chromosome 17 and Tnf as a candidate gene.

Animals↗
PubMed1997

Genetic modeling of susceptibility to nitrogen dioxide-induced lung injury in mice.

We investigated the mode of inheritance of susceptibility to nitrogen dioxide (NO2)-induced lung injury in inbred mice. Susceptible C57BL/6J (B6) and resistant C3H/HeJ (C3) mice, as well as F1, F2, and backcross (BX) populations derived from them, were exposed to 15 parts per million NO2 for 3 h. Six hours after exposure, animals were lavaged, and differential cell counts and cell viability (cytotoxicity) were measured. Statistically significant (P < 0.05) differences in numbers of lavageable macrophages, epithelial cells, and dead cells were found between inbred strains. Distributions of cellular responses in F1 progeny overlapped both progenitors, and mean responses were intermediate. In C3:BX progeny, ranges of responses to NO2 closely resembled C3 mice, and means were not significantly different between populations. Ranges of cellular responses to NO2 in B6:BX and intercross progeny overlapped both progenitors; mean responses of both populations were intermediate to progenitors. Segregation analyses tested goodness of fit of phenotyping data with various inheritance models, and the highest likelihood for each cell response to NO2 was for the hypothesis two-unlinked loci general. We conclude that there are likely two major unlinked genes that account for differential susceptibility to acute NO2 exposure. The chromosomal location of the genes is not known.

Animals↗
PubMed1997

Genetic control of differential baseline breathing pattern.

The purpose of the present study was to determine the genetic control of baseline breathing pattern by examining the mode of inheritance between two inbred murine strains with differential breathing characteristics. Specifically, the rapid, shallow phenotype of the C57BL/6J (B6) strain is consistently distinct from the slow, deep phenotype of the C3H/HeJ (C3) strain. The response distributions of segregant and nonsegregant progeny were compared with the two progenitor strains to determine the mode of inheritance for each ventilatory characteristic. The BXH recombinant inbred (RI) strains derived from the B6 and C3 progenitors were examined to establish strain distribution patterns for each ventilatory trait. To establish the mode of inheritance, baseline breathing frequency (f), tidal volume, and inspiratory time (TI) were measured five times in each of 178 mature male animals from the two progenitor strains and their progeny by using whole body plethysmography. With respect to f and TI, the two progenitor strains were consistently distinct, and segregation analyses of the inheritance pattern suggest that the most parsimonious genetic model for response distributions of f and TI is a two-loci model. In similar experiments conducted on 82 mature male animals from 12 BXH RI strains, each parental phenotype was represented by one or more of the RI strains. Intermediate phenotypes emerged to confirm the likelihood that parental strain differences in f and TI were determined by more than one locus. Taken together, these studies suggest that the phenotypic difference in baseline respiratory timing between male B6 and C3 mice is best explained by a genetic model that considers at least two loci as major determinants.

Animals↗
PubMed1996

Inhalation of acid coated carbon black particles impairs alveolar macrophage phagocytosis.

A flow-past nose-only inhalation system was used for the co-exposure of mice to carbon black aerosols (CBA) and sulfur dioxide (SO2) at varying relative humidities (RH). The conversion of SO2 to sulfate (SO4(-2)) on the CBA, at a fixed aerosol concentration, was dependent on RH and SO2 concentration. The effect of the aerosol-gas mixture on alveolar macrophage (AM) phagocytosis was assessed three days following exposure for 4 h. Exposure to 10 mg/m3 CBA alone at low RH (10%) and high RH (85%), to 10 ppm SO2 alone at both RH, and to the mixture at low RH had no effect on AM phagocytosis. In contrast, AM phagocytosis was significantly suppressed following co-exposure at 85% RH, the only circumstance in which significant chemisorption of the gas by the aerosol and oxidation to SO4(-2) occurred. The results suggest that fine carbon particles can be an effective vector for the delivery of toxic amounts of SO4(-2) to the periphery of the lung.

Administration, Inhalation↗
PubMed1996

Vitamin A deficiency enhances ozone-induced lung injury.

The present study determined the effects of vitamin A (vA) deficiency on the responses to ozone (O3) challenges in two inbred strains of mice that are differentially susceptible to O3-induced lung inflammation. Susceptible C57BL/6J (B6) and resistant C3H/HeJ (C3) dams at 2 wk gestation were fed test diets containing either 0 or 10 micrograms retinol/g diet. In mice that were maintained on vA-sufficient (vA+) diet, lung and liver tissue concentrations of vA and retinyl palmitate (RP) were significantly (P<0.05) lower in the B6 strain compared with C3, as measured by high-performance liquid chromatography techniques. vA and RP levels were significantly (P<0.05) reduced in lung and liver tissues of 8-wk old B6 and C3 mice that were maintained on a vA deficient (vA-) diet. vA+ and vA- mice of both strains were exposed to air or 0.3 ppm O3/72 h, and lung injury was assessed by differential cell count and total protein concentration in bronchoalveolar lavage (BAL) returns. O3 exposure caused significantly (P<0.05) greater increases in inflammatory cells and a total protein in BAL returns of vA+ B6 mice than vA+ C3 mice. vA deficiency significantly (P<0.05) enhanced O3-induced increases in polymorphonuclear leukocytes in C3 mice and epithelial cells loss in both strains. Compared with vA+ mice, lung permeability was also significantly (P<0.05) enhanced in vA- mice of both strains exposed to O3. vA replacement partially reversed the O3-induced lung injury that was enhanced by vA- diet. Results indicate that vA may have an important role in the pathogenesis of O3-induced lung injury in differentially susceptible inbred strains of mice.

Analysis of Variance↗
PubMed1996

Mass cells contribute to O3-induced epithelial damage and proliferation in nasal and bronchial airways of mice.

Ozone (O3) exposure produces inflammation in the airways of humans and animal models. However, the mechanism by which O3 affects these changes is uncertain. Mast cells are strategically located below the epithelium of the airways and are capable of releasing a number of proinflammatory mediators. We tested the hypothesis that mast cells contribute to inflammation, epithelial sloughing, and epithelial proliferation in the nasal and terminal bronchiolar murine airways after O3 exposure. Mast cell-sufficient (+/+), mast cell-deficient (W/Wv), and mast cell-repleted [bone marrow-transplanted (BMT) W/Wv] mice were exposed to 2 ppm O3 or filtered air for 3 h. Nasal and bronchoalveolar lavage fluids were collected 6 and 24 h after exposure. Differential cell counts and protein content of the lavage fluids were used as indicators of inflammation and permeability changes in the airways. O3-induced epithelial injury was assessed by light microscopy, and O3-induced DNA synthesis in airway epithelium was estimated by using a 5-bromo-2'-deoxyuridine-labeling index in the nasal and terminal bronchiolar epithelia. Relative to air control mice, O3 caused significant increases in inflammation, epithelial injury, and epithelial DNA synthesis in +/+ mice. There was no significant effect of O3 exposure on any measured parameter in the W/Wv mice. To further assess the role of mast cells in O3-induced epithelial damage, mast cells were restored in W/Wv mice by BMT from +/+ congeners. Relative to sham-transplanted W/Wv mice, O3 caused significant increases in epithelial damage and DNA synthesis as well as inflammatory indicators in BMT W/Wv mice. These observations are consistent with the hypothesis that mast cells significantly modulate the inflammatory and proliferative responses of the murine airways to O3.

Animals↗
PubMed1996

PAF-induced airways hyperreactivity is modulated by mast cells in mice.

We tested the hypothesis that mast cells contribute to platelet-activating factor (PAF)-induced airways hyperreactivity and hyperpermeability in mice. Airways reactivity to acetylcholine (ACh) and lung permeability to Evans blue (EB) dye were measured before and after PAF challenge in genetically mast cell-deficient (WBB6F1 W/Wv) and normal congenic (WBB6F1 +/+) mice, as well as mast cell-reconstituted (BMT W/Wv) mice. In addition, prostaglandin D2 (PGD2), a mast cell-specific mediator, was measured in the bronchoalveolar lavage (BAL) from +/+ and W/Wv mice to determine if lung mast cell activation was a consequence of PAF challenge. Genetically PAF-sensitive AKR/J mice were also treated with the mast cell stabilizer nedocromil prior to assessment of PAF effects on ACh reactivity. Intravenous PAF (10 micrograms/kg) induced a significant (P < 0.05) increase in airways reactivity to ACh (25 micrograms/kg) in both +/+ (371 +/- 52%) and W/Wv (122 +/- 24%) mice. There was a significantly greater increase in +/+ compared with W/Wv mice. PAF-induced hyperreactivity to ACh in BMT W/Wv mice (191 +/- 44%) was significantly (P < 0.05) greater than age-matched W/Wv mice (80 +/- 16%), but not significantly different from age-matched +/+ mice (153 +/- 44%). PAF (10 micrograms/kg) also significantly (P < 0.5) increased lung permeability in +/+ and W/Wv mice, but there was no significant difference between groups. BAL PGD2 increased significantly in +/+ mice following PAF challenge (559 +/- 24 ng/ml) compared with vehicle controls (152 +/- 8 pg/ml). There was no significant increase in BAL PGD2 from W/Wv mice. Nedocromil pretreatment significantly (P < 0.05) decreased PAF-induced hyperreactivity in AKR/J mice but not in W/Wv mice (P > 0.05). We conclude that mast cells contribute significantly to PAF-induced hyperreactivity but not hyperpermeability in mice.

Acetylcholine↗
PubMed1995

Ozone-induced decrease of mouse tracheal potential is not secondary to cellular inflammation.

Acute exposure of C57BL/6J (B6) mice to ozone (O3) causes decreased in vivo tracheal electrical potential difference (PD). To investigate the role of inflammation in this response we measured O3 effects in B6 mice pretreated with indomethacin (5 mg/kg), colchicine (3 mg/kg), or cyclophosphamide (30 mg/kg x 7 days). Mice were exposed to 2 ppm O3 or air for 3 hr and allowed to recover for 0, 3, 6, 9, or 12 hr. Tracheal PD was measured under pentobarbital anesthesia using a capped agar bridge inserted into the upper trachea through a neck incision. After measurement of PD, bronchoalveolar lavage (BAL) was performed and total cells, polymorphonuclear leukocytes (PMNs), and protein were determined. As previously reported, O3 exposure decreased PD and increased BAL total cells, PMNs, and protein. O3-induced changes in PD and PMNs were maximal 6-9 hr after exposure. Indomethacin prevented the O3-induced change in PD but had no effect on BAL total cells or PMNs. Colchicine attenuated O3-induced increases in PMNs and cyclophosphamide decreased O3 effects on both BAL total cells and PMNs but neither drug affected the PD response. None of the drugs significantly altered O3-induced increases in BAL protein. The indomethacin sensitivity of O3-induced changes in PD may reflect a role of cyclooxygenase products in that response. However, drugs known to inhibit PMN function did not affect O3-induced changes in PD. We suggest that cellular inflammation is not required for the tracheal electrophysiological response to acute O3 exposure.

Animals↗
PubMed1995

Structure and DNA sequence of the mouse MnSOD gene.

Oxidative damage to the cell has been implicated in the pathogenesis of a number of disorders, including chronic inflammation, aging, and cancer. Manganese superoxide dismutase (Mn-SOD) plays a major role in the protection of the mitochondrion from oxidative damage due to superoxide radicals and other excited oxygen species. In this report we describe the genomic organization and DNA sequence of the murine MnSOD gene. This gene is interrupted by four introns. The coding sequence of this gene was examined in C57BL/6J and C3H/HeJ mice that are SUSCEPTIBLE AND RESISTANT, respectively, to the pulmonary injuries induced by the inhaled oxidants, ozone, and hyperoxia. Since the predicted amino acid sequence for MnSOD does not differ for these strains, nor does the size or steady-state level of this transcript, biologic variability in the pulmonary inflammatory response to ozone and hyperoxia does not arise from an altered gene structure. Examination of the noncoding sequence revealed a dC.dA polymorphism in intron 2 and a StyI RFLV in intron 4 of the MnSOD gene. These sequence and mapping data provide the basis for continued study of biologic variability in the MnSOD gene as a cause of disease.

Amino Acid Sequence↗
PubMed1995

Genetic susceptibility to ozone exposure.

Because of the impact that oxidizing air pollutants such as ozone (O3) may have on public health, identification of factors that influence susceptibility to exposure remains a critical issue. The role of genetic background as a susceptibility factor is becoming increasingly clear. In this paper, evidence is reviewed which suggests that susceptibility to O3 is a heritable trait in humans. Experimental studies are also described that characterize the mode of inheritance of O3-induced lung injury in inbred strains of mice. It is suggested that future investigations should strive to identify phenotypic markers of susceptibility as a means to identify individuals who are genetically at risk for the development of oxidant-induced lung injury.

Animals↗
PubMed1995

Genetic control of susceptibility to ozone-induced changes in mouse tracheal electrophysiology.

Genetic factors influence the responses of humans and rodents to ozone (O3) inhalation. We previously demonstrated differential O3-induced decreases of tracheal potential (VT) in C57BL/6J (B6) and C3H/HeJ (C3) strain mice. To characterize the genetic basis of this strain-specific response, we measured VT in progeny of B6 and C3 strain mice and in six additional inbred strains of mice 6 h after O3 exposures (2 ppm x 3 h). First filial generation (F1) mice and second generation backcrosses with the resistant parent were uniformly resistant. The distribution of VT in second generation backcrosses with the susceptible parent resembled that of a population composed of resistant and susceptible mice in a 1:1 ratio. These data suggested simple autosomal recessive inheritance of susceptibility. However, overlapping distributions prevented statistical confirmation of that hypothesis. Strain screening revealed a susceptible phenotype in 129/J, A/J, B6, C3HeB/FeJ, and SJL/J and a resistant phenotype in AKR/J, C3, and CBA/J inbred mouse strains. Because this pattern of susceptibility to changes in VT differs from that of susceptibility to lung inflammation, the genetic factors that determine these two responses to acute O3 are not identical.

Animals↗
PubMed1995

Expression of ICAM-1 in airway epithelium after acute ozone exposure in the mouse.

We investigated the time course and regional distribution of the expression of intercellular adhesion molecule-1 (ICAM-1) on airway epithelial cells and the polymorphonuclear leukocyte (PMN) inflammatory response in the lung after acute exposure to ozone (O3). C57BL/6J mice were exposed to air or 2 ppm O3 for 3 h and killed immediately or 3, 6, 9, or 21 h after exposure. Expression of ICAM-1 was examined by immunohistochemical staining of frozen sections. PMN influx was evaluated by lavage and by histochemical staining of myeloperoxidase (MPO) and measurement of tissue MPO activity. ICAM-1 expression exhibited regional selectivity and temporal patterns that were unique to each region. Upregulation of ICAM-1 expression on the epithelial cells in the trachea, and to a lesser extent in the lobar and segmental bronchi, was observed 3-9 h after exposure and remained present at 21 h. Enhanced ICAM-1 expression in bronchioles and terminal bronchiole/alveolar duct regions was evident earlier (immediately to 3 h after exposure) but returned to baseline levels by 21 and 9 h, respectively. Maximal ICAM-1 expression and PMN influx in the lung parenchyma were concurrently observed at 3 h, followed by transepithelial migration of PMNs to the airway lumen. These results demonstrate regional variations in airway inflammatory activity and are supportive of the notion that upregulation of ICAM-1 on the airway epithelium may play a role in local regulation of PMN influx to the airways after acute O3 exposure.

Administration, Inhalation↗
PubMed1995

Susceptibility to platelet-activating factor-induced airway hyperreactivity and hyperpermeability: interstrain variation and genetic control.

Platelet-activating factor (PAF) is a proinflammatory mediator known to elicit changes in airway reactivity and vascular permeability, and it may also have a role in the development and progression of acute respiratory distress syndrome and asthma. We have developed a mouse model to test the hypothesis that these traits were controlled by a single gene and were mechanistically related. We further hypothesized that there was a relationship between PAF-induced hyperreactivity and baseline reactivity to acetylcholine (ACh). Among eight inbred strains of mice that exhibited significant interstrain variation in ACh reactivity, intravenous PAF induced 16 to 278% increases in reactivity to ACh (25 micrograms/kg). PAF also elicited 95 to 307% increases in lung permeability as measured by Evans blue extravasation. Both reactivity and permeability changes induced by PAF were blocked by a PAF receptor antagonist (L-659,989). Strain distribution patterns for baseline reactivity to ACh and PAF-induced hyperreactivity and lung permeability were not significantly concordant, and suggest that the variables were not interdependent. Progeny derived from AKR/J (PAF hyperresponsive) and C3H/HeJ (PAF hyporesponsive) mice were characterized for their PAF responsiveness as determined by PAF-induced hyperreactivity and hyperpermeability. The ratios of hyperresponsive and hyporesponsive phenotypes in outcross progeny were compared to those predicted for Mendelian inheritance and assessed for relatedness by chi 2 and cosegregation analyses. Results suggested that PAF-induced hyperreactivity was controlled by a single gene, but PAF-induced hyperpermeability was controlled by a more complicated interaction of factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1995

The effects of ozone on immune function.

A review of the literature reveals that ozone (O3) exposure can either suppress or enhance immune responsiveness. These disparate effects elicited by O3 exposure depend, in large part, on the experimental design used, the immune parameters examined as well as the animal species studied. Despite the apparent contradictions, a general pattern of response to O3 exposure can be recognized. Most studies indicate that continuous O3 exposure leads to an early (days 0-3) impairment of immune responsiveness followed, with continued exposures, by a form of adaptation to O3 that results in a re-establishment of the immune response. The effects of O3 exposure on the response to antigenic stimulation also depend on the time at which O3 exposure occurred. Whereas O3 exposure prior to immunization is without effect on the response to antigen, O3 exposure subsequent to immunization suppresses the response to antigen. Although most studies have focused on immune responses in the lung, numerous investigators have provided functional and anatomical evidence to support the hypothesis that O3 exposure can have profound effects on systemic immunity.

Animals↗
PubMed1995

Chronic ethanol consumption increases hepatic sinusoidal contractile response to endothelin-1 in the rat.

Recent evidence suggests that hepatic stellate cells function as liver-specific pericytes that are highly contractile in response to endothelin-1 (ET-1). Liver injury has been shown to lead to "activation" of stellate cells producing a phenotypic change to a more myofibroblastic cell type including loss of vitamin A and increased contractility. The present study was undertaken to test the effects of short-term chronic ethanol consumption (36% of total calories for 5 weeks according to the Lieber-DeCarli protocol) on hepatic vitamin A storage, expression of smooth muscle alpha-actin, and sinusoidal contractility in Sprague-Dawley rats. Using in vivo epifluorescence video microscopy, we quantified the number of sites of vitamin A fluorescence (purportedly stellate cells) and assessed sinusoidal microhemodynamics at baseline and during a 20-minute infusion period of ET-1 (1 pmol * 100 g body weight [bw]*1*min-1). Retinol and retinyl palmitate were measured after the experiment by means of high-pressure liquid chromatography (HPLC). A highly significant decrease in liver retinyl palmitate level (control: 622.5 +/- 50.9; ethanol: 273.0 +/- 38.0 microgram/g liver; P< .001) was found that correlated with a decrease in sites of vitamin A fluorescence (control: 531.4 +/- 76.1; ethanol: 141.1 +/- 30.2* mm-2; r = .82, P <.001). Concomitantly scattered expression of smooth muscle alpha-actin in sinusoids was observed. Although sinusoidal hemodynamics were not affected at baseline, a significant increase in sinusoidal contractility on endothelin-1 infusion (e.g., sinusoidal resistance [% of baseline value]: control: 10 minutes: 288.7 +/- 71.7, 20 minutes: 200.5 +/- 46.9; ethanol: 10 minutes: 1,916.0 +/- 701.7, 20 minutes: 656.8 +/- 103.3; P < .05 and .01, respectively) was observed. These data indicate that chronic ethanol consumption in this moderate model initiates stellate cell activation. Increased sinusoidal responsiveness to the vasoconstrictor ET-1 in vivo may contribute to the increased susceptibility of ethanol-fed rats to secondary stresses that increase ET-1 expression, such as endotoxemia.

Actins↗