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Biomedical subjects

S G Von Essen

Publications and source records attributed to S G Von Essen.

17 recordsLinked to original sources
PubMed2004

Hog barn dust extract augments lymphocyte adhesion to human airway epithelial cells.

The dust of hog confinement facilities induces airway inflammation. Mechanisms by which this dust modulates inflammation are not completely defined, although it is clear that exposure to dust can modulate both epithelial cell and inflammatory cell function. In this work, we demonstrate that airway epithelial cell (BEAS-2B) treatment with hog barn dust extract (HDE) results in augmentation of peripheral blood lymphocyte adhesion to epithelial cell cultures in vitro. The augmentation of lymphocyte adhesion to epithelial cells is dependent on the concentration of HDE and time of HDE exposure, with twofold increases observed by 3 h and maintained at 24 h. Similar results are seen with primary human bronchial epithelial cells in culture. Lymphocyte adhesion to epithelial cells is inhibited in a concentration-dependent fashion by the treatment of epithelial cells with antibody to intercellular adhesion molecule-1 (ICAM-1). In addition, HDE exposure of epithelial cells results in an approximate twofold increase in ICAM-1 expression as determined by flow cytometry analysis. Pretreatment of epithelial cells with a protein kinase C-alpha (PKC-alpha) inhibitor, Gö-6976, also inhibited subsequent lymphocyte adhesion to HDE-exposed epithelial cells. These data suggest that airway epithelial cell HDE exposure enhances subsequent lymphocyte adhesion to epithelial cells that is mediated in part by HDE modulation of ICAM-1 expression and PKC-alpha.

Agriculture↗
PubMed2003

The relationship between agricultural environments and olfactory dysfunction.

OBJECTIVES: To examine the olfactory ability of farmers and identify exposures in agricultural environments associated with olfactory loss. STUDY DESIGN: Cross-sectional. METHODS: 405 individuals (214 males and 191 females) completed a questionnaire assessing agricultural exposures, health status, and olfactory history. Participants then completed a scratch-and-sniff 12-item odor identification test. Data analysis was conducted using the method of least squares to fit general linear models. Equality of outcome measures (the number of correctly identified odorants) between groups was evaluated using the Wilcoxon rank sum test. Differences were considered to be significant at the 0.05 level. RESULTS: Approximately 80% of participants reported active participation in farm work. Farmers correctly identified an average of 9.3 of 12 odorants, compared to 10.1 of 12 correctly identified by non-farmers, a difference that was not statistically significant (p = 0.2). Participants reporting sneezing after handling soybeans, wheat, or oats scored significantly lower than those without symptoms. There were suggestive associations between olfactory ability and exposure to anhydrous ammonia, history of wheezing and asthma, and a history of flu-like illness after farm work. CONCLUSIONS: Results indicate that, in general, farming is not associated with olfactory loss. However, we identified certain groups of farmers with inflammatory-type reactions who appeared to be susceptible to olfactory loss. The association between inflammatory reactions or conditions and olfactory loss is a novel finding.

Adolescent↗
PubMed2002

Hog barn dust extract stimulates IL-8 and IL-6 release in human bronchial epithelial cells via PKC activation.

Hog barn workers have an increased incidence of respiratory tract symptoms and demonstrate an increase in lung inflammatory mediators, including interleukin (IL)-8 and IL-6. Utilizing direct kinase assays for protein kinase C (PKC) activation, we demonstrated that dust from hog confinement facilities, or hog dust extract (HDE), augments PKC activity of human airway epithelial cells in vitro. A 5% dilution of HDE typically stimulates an approximately twofold increase in human bronchial epithelial cell (HBEC) PKC activity compared with control medium-treated cells. This increase in PKC is observed with 15 min of HDE treatment, and kinase activity reaches peak activity by 1-2 h of HDE treatment before returning to baseline PKC levels between 6 and 24 h. The classic PKC inhibitor, calphostin C, blocks HDE-stimulated PKC activity and associated IL-8 and IL-6 release. Desensitization to HDE stimulation of PKC activation does not appear to occur because subsequent exposures to HDE after an initial exposure result in further augmentation of PKC. Detoxification of HDE with polymyxin B to remove endotoxin did not change PKC activation or IL-8 release, suggesting that endotoxin is not solely responsible for HDE augmentation of PKC. These data support the hypothesis that HDE exposure augments HBEC IL-8 and IL-6 release via a PKC-dependent pathway.

Animal Feed↗
PubMed2000

Exercise training effect on obstructive sleep apnea syndrome.

The role, if any, of exercise training in the management of individuals with obstructive sleep apnea syndrome (OSAS) is unclear. Anecdotally, patients have reported improvement in symptoms with regular participation in an exercise regime. In this study, we evaluated the effects of an exercise training program and weight loss on physical and subjective measures associated with OSAS. Nine subjects with mild to moderate OSAS completed a six month supervised exercise program. Pre and post-training measures on polysomnographic testing, physical training, anthropometric measures, quality of life (QOL), daytime somnolence and mood states were assessed. A significant decrease in the AHI (p=0.002) was noted along with improvements (p<0.05) in total sleep time, sleep efficiency, number of awakenings/hour, arousals/hour, apnea index and mean exercise training workloads. Significant decreases (p<.001) in weight (-6.2 kg) and body mass index (-1.6) were observed. Evaluation of QOL measures by the Health Status Questionnaire, Profile of Mood States and Epworth Sleepiness Scale showed significant changes in health status, affective state, and a decrease in daytime somnolence. Regular exercise training had a positive impact on the AHI, aerobic capacity, body mass index and QOL. However, exercise training alone was not an adequate intervention strategy for most individuals with OSAS but may serve well as an adjunct treatment strategy in the conservative management of individuals with mild to moderate OSAS.

Adult↗
PubMed1998

Respiratory tract inflammation in swine confinement workers studied using induced sputum and exhaled nitric oxide.

OBJECTIVE: To further define the asthma-like syndrome seen in swine confinement workers. DESIGN: A cross-sectional study was performed at a swine confinement facility in rural Nebraska and at the University of Nebraska Medical Center, Omaha, Nebraska. PARTICIPANTS: 24 swine confinement workers and 14 urban normal control subjects. All subjects completed a questionnaire concerning respiratory complaints. We performed hypertonic saline challenges on the swine confinement workers and control subjects in order to induce expectoration of sputum. Cell counts and cell differentials were determined in the induced sputum samples. Nasal, mean, and peak exhaled nitric oxide was measured in both groups. Spirometry was also done. RESULTS: Swine confinement workers were significantly more likely to report wheezing, cough, and sinusitis symptoms than controls (p = .003). Macrophages were significantly elevated in the induced sputum samples of the swine confinement workers vs the control subjects (0.59 macrophages/mL +/- 0.1 SEM vs 0.36 +/- .16; p = .006), while there was no difference in numbers of neutrophils. No eosinophils were observed. A small elevation in mean exhaled nitric oxide was seen in the swine confinement workers compared to normal controls (11.7 ppb +/- 0.6 SEM vs 10.2 +/- 1.6; p = 0.023). Spirometry values did not differ statistically between swine confinement workers and the control group. CONCLUSIONS: Swine confinement workers have signs and symptoms of lower respiratory tract inflammation when studied using induced sputum and exhaled nitric oxide. Findings in the swine confinement workers differ from those in asthmatics and chronic bronchitis.

Adult↗
PubMed1998

Health and safety risks in production agriculture.

Production agriculture is associated with a variety of occupational illnesses and injuries. Agricultural workers are at higher risk of death or disabling injury than most other workers. Traumatic injury commonly occurs from working with machinery or animals. Respiratory illness and health problems from exposures to farm chemicals are major concerns, and dermatoses, hearing loss, certain cancers, and zoonotic infections are important problems. Innovative means of encouraging safe work practices are being developed. Efforts are being made to reach all groups of farmworkers, including migrant and seasonal workers, farm youth, and older farmers.

Agricultural Workers' Diseases↗
PubMed1996

Measurement of exhaled nitric oxide by three different techniques.

The purpose of the study was to compare exhaled nitric oxide (NO) determined by three techniques. Ninety-one subjects performed a slow vital capacity maneuver: (1) through the mouth directly into a NO chemiluminescence analyzer (peak oral NO), (2) through the mouth into a collection bag (mean oral NO), and (3) through the nose into a collection bag (mean nasal NO). Peak oral NO was higher in patients with asthma (n = 18, 174.2 +/- 27.0 ppb), but lower in smokers (n = 36, 39.6 +/- 4.8 ppb) compared with nonsmoking control subjects (n = 23, 105.5 +/- 8.4 ppb, p < 0.05 both comparisons). Mean oral NO levels were significantly lower than peak oral NO levels (p < 0.05), but still higher in patients with asthma in comparison with nonsmoking healthy control subjects and asymptomatic smokers (27.2 +/- 3.5 versus 14.5 +/- 1.1 and 7.3 +/- 0.7 ppb, respectively, p < 0.05). In contrast, there was no significant difference in mean nasal NO levels between the three groups. Peak oral NO and mean oral NO levels correlated (r = 0.772, p < 0.0001). Determination of exhaled oral NO levels is qualitatively independent of the technique used, but nasal exhalation may affect NO determination in conditions associated with airway inflammation.

Adult↗
PubMed1995

Grain dusts and grain plant components vary in their ability to recruit neutrophils.

Occupational exposure to grain dusts can cause bronchitis, particularly to grain sorghum dust. Bronchitis is associated with the presence of increased numbers of neutrophils. To determine how grain dusts could cause neutrophil recruitment to the airways, extract of whole-grain sorghum, corn, and soybean dusts and of pulverized components of these plants were made with Hanks balanced salt solution (HBSS) and used in direct neutrophil chemotaxis experiments. The glume of the grain sorghum plant, the structure holding the seeds in place, caused the migration of the greatest number of neutrophils compared to HBSS [132 +/- 7 vs. 60 cells/high-power field (hpf) +/- 2 SEM, p < .001], followed by whole-grain sorghum dust (121 +/- 5 cells/hpf). Next, bovine bronchial epithelial cells (BBECs) were obtained from fresh lungs and grown to near confluence before challenge with a 10% solution of grain dust and grain plant extracts. The grain sorghum glume and whole-grain sorghum dusts caused release of the greatest amount of neutrophil chemotactic activity (NCA) from BBECs compared to the medium M199 negative control (141 +/- 6 and 153 +/- 7, respectively, vs. 64 cells/hpf +/- 3 SEM, p < .001). The ability to cause neutrophils to migrate by direct and indirect means did not correlate with levels in the grain dusts of endotoxin, which is known to cause release of NCA from bronchial epithelial cells. Therefore, this article describes additional mechanisms by which grain dusts can cause pulmonary inflammation and that are independent of endotoxin levels.

Animals↗
PubMed1995

Neutrophilic respiratory tract inflammation and peripheral blood neutrophilia after grain sorghum dust extract challenge.

STUDY OBJECTIVE: To determine if inhalation of grain sorghum dust in the laboratory would cause neutrophilic upper and lower respiratory tract inflammation in human volunteers, as well as systemic signs of illness. DESIGN: Prospective. SETTING: University of Nebraska Medical Center. PARTICIPANTS: Thirty normal volunteers. INTERVENTIONS: Inhalation challenge with 20 mL of a nebulized solution of filter-sterilized grain sorghum dust extract (GSDE). One group received prednisone, 20 mg for 2 days, prior to the challenge. MEASUREMENTS AND RESULTS: Bronchoscopy with bronchoalveolar lavage (BAL) was performed 24 h after challenge, with samples collected as bronchial and alveolar fractions. Findings included visible signs of airways inflammation, quantified as the bronchitis index. The percentage of bronchial neutrophils was significantly increased in those challenged with GSDE vs the control solution, Hanks' balanced salt solution (40.3 +/- 4.5% vs 14.3 +/- 5.1%, p < or = .01). Similar findings were seen in the alveolar fraction. Pretreatment with corticosteroids did not prevent the rise in neutrophils recovered by BAL. Peripheral blood neutrophils were also increased in volunteers challenged with the grain dust extract. To explain the increase in peripheral blood neutrophil counts, the capacity of the peripheral blood neutrophils to migrate in chemotaxis experiments was examined. The results demonstrate an increase in peripheral blood neutrophils and an increase in chemotactic responsiveness. CONCLUSIONS: Inhalation challenge with a grain dust extract causes respiratory tract inflammation and a peripheral blood neutrophilia. One reason for this may be an increase in activated peripheral blood neutrophils.

Adult↗
PubMed1994

Neutrophil chemotaxis to extracts of grain plant components.

Exposure to grain dust has been associated with a neutrophilic bronchitis. In vitro studies suggest several possible mechanisms for recruitment of neutrophils, including direct chemotaxis to aqueous grain dust extracts and release of chemotactic activity by bronchial epithelial cells in response to challenge with grain dust extracts.

Animals↗
PubMed1993

General vs local anesthesia. Effect on bronchoalveolar lavage findings.

Bronchoalveolar lavage (BAL) can be performed with the patient undergoing either local or general anesthesia (GA). This study investigates whether the type of anesthesia affects BAL fluid and cell recovery. Eighty patients, were selected for study. Fluid recoveries were significantly less in the GA group for both the bronchial and alveolar lavages. The differences were confirmed for BAL fluid recovery in a subsequent group of 120 unselected patients. Bronchoscope size did not appear to affect recovery, nor did anesthesia time; BAL fluid recovery from patients with respiratory failure who were intubated and mechanically ventilated was similar to that in the GA group, suggesting that lower recovery rates may be due to mechanical ventilation. The BAL fluid cell counts were related to fluid recovery, but airway neutrophils represented a higher percentage of BAL lavage fluid cells in the GA lavages, independent of differences in the volume of lavage fluid recovered.

Adult↗
PubMed1992

Bronchial epithelial cells release neutrophil chemotactic activity in response to tachykinins.

The purpose of this study was to determine whether substance P (SP), neurokinin A (NKA), and neurokinin B (NKB) induce the release of neutrophil chemotactic activity (NCA) from bovine bronchial epithelial cells (BBEC) and whether neutral endopeptidase (NEP), a membrane-bound metalloenzyme that hydrolyzes tachykinins, modulates these effects. BBEC monolayers were exposed to SP, NKA, and NKB in the absence or presence of phosphoramidon (10(-6) M), a selective NEP inhibitor, for 72 h. Using a modified blind-well in vitro neutrophil chemotaxis assay, we found that tachykinin-exposed BBEC culture supernatant fluids induced significant neutrophil chemotaxis compared with supernatants obtained from unstimulated BBEC. Maximal effect was observed after 48 h of incubation and at SP concentration of 10(-13) M [92 +/- 3 (SP) vs. 64 +/- 2 (media) cells/high-power field (HPF), mean +/- SE, n = 7, P less than 0.05]. Release of NCA was mediated by the COOH-terminal of the SP molecule. The rank order of potency of tachykinins in inducing release of NCA was SP greater than NKA = NKB. SP-induced response was significantly potentiated by phosphoramidon (109 +/- 3 vs. 92 +/- 3 cells/HPF, n = 7, P less than 0.05), whereas other proteinase inhibitors had no effect. The released NCA was composed of protein and lipid-soluble components. These data indicate that mammalian tachykinins induce the release of NCA from BBEC and that NEP modulates these effects. We suggest that tachykinins regulate neutrophil recruitment into the lower respiratory tract, in part, by inducing the release of NCA from airway epithelial cells.

Animals↗
PubMed1991

Agricultural disorders of the lung.

Agricultural workers are at risk for developing many respiratory tract disorders. Crop production disorders include chronic bronchitis, asthma, organic dust toxicity syndrome, chemical poisoning, farmer lung, and silo-filler disease. Livestock production disorders include toxic manure poisoning (dung lung) and several zoonoses. Radiographic manifestations can be classified into three patterns: (a) normal findings, characteristic of chronic bronchitis, asthma, or organic dust toxicity syndrome; (b) acute diffuse interstitial or alveolar pattern, characteristic of farmer lung, silo-filler disease, dung lung, and chemical poisoning; and (c) chronic interstitial pattern in the upper lobes (farmer lung) or lower lobes (silo-filler disease, paraquat poisoning). Differential diagnosis is aided by knowledge that most of these disorders have a seasonal presentation. Zoonoses generally exhibit focal areas of consolidation in the lung: The type of splenic calcification, presence of mediastinal or hilar adenopathy, and development of bronchiectasis are additional findings useful in differentiating these rare infections.

Agricultural Workers' Diseases↗
PubMed1991

Bronchoscopy with bronchoalveolar lavage causes neutrophil recruitment to the lower respiratory tract.

Bronchoscopy with bronchoalveolar lavage (BAL) is a technique now widely utilized for both clinical and investigational purposes. At times, it is useful to perform bronchoscopy with BAL in a serial fashion. However, previous work in animals indicates that bronchoscopy with BAL can cause lower respiratory tract inflammation. To determine if BAL also causes lower respiratory tract inflammation in humans, sequential bronchoscopy with BAL was performed in 30 human subjects. Inflammation was evaluated using a quantitative visual assessment of bronchitis and by BAL. BAL was performed by instilling and aspirating five 20-ml aliquots of saline in each of three areas of the lung. The fluid returned from the first aliquot from each site was pooled as the bronchial fraction, and that from the remaining four aliquots was pooled as the alveolar fraction. Each volunteer was restudied at 2, 7, 24 or 72 h. Findings at the second bronchoscopy with BAL included an elevation in visual signs of large airways inflammation, which was greatest at 24 h. Bronchial neutrophils increased significantly, with the greatest effect seen at 7 h (5.3 +/- 2.0 versus 59.5 +/- 11.0%, SEM). The effect was most pronounced in the area of the lung previously lavaged, but was also seen in lobes that had not received BAL at the first bronchoscopy. Alveolar neutrophils also increased, with the maximal effect also seen at 7 h. Visible bronchial inflammation, bronchial neutrophils, and alveolar neutrophils returned to the normal range by 72 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Neutrophil chemotactic factors in bacterial pneumonia.

The influx of neutrophils into the lung is a prominent feature in patients with bacterial pneumonia. Since neutrophils migrate in response to chemotactic factors, chemotactic activity was evaluated in bronchoalveolar lavage (BAL) fluid obtained from 12 patients with bacterial pneumonia and ten normal control subjects. Chemotactic activity was greatly elevated in the BAL fluid of the pneumonia patients compared with control subjects (p less than 0.01). To partially characterize the chemotactic factors present in the lavage fluid of the patient group, molecular sieve chromatography was performed on the lavage fluid, and at least three peaks of chemotactic activity were identified. Since the molecular weight of the smaller peaks approximated the molecular weight of two known chemotactic factors, C5a and leukotriene B4, these factors were measured in lavage fluid by radioimmunoassay. C5a was detectable in none of the normal subjects but was detectable in four of 14 BAL samples obtained from the patients. Leukotriene B4 was detectable in all subjects and was significantly elevated in the pneumonia patients (552 +/- 95 vs 81 +/- 16 pg/ml, p less than 0.01). These findings demonstrate that elevated neutrophil chemotactic activity is present in the lungs of patients with bacterial pneumonia and suggest that C5a and leukotriene B4 may account, at least in part, for this increase.

Adolescent↗
PubMed1988

Mechanisms of neutrophil recruitment to the lung by grain dust exposure.

Inhalation of grain dusts can cause symptoms of both acute and chronic bronchitis, which has been associated with a neutrophilic inflammatory response in the lung. Since this influx of neutrophils may potentially result in bronchial injury, mechanisms of neutrophil recruitment to grain dust were examined. Sterile, aqueous grain dust extracts were prepared from settled dusts of grain sorghum, corn, oats, and soybeans. The extracts were evaluated for their ability to directly attract human neutrophils using a blindwell neutrophil chemotaxis assay. Each extract was found to possess significant chemotactic activity compared to control (p less than 0.01). To evaluate if the dusts could attract neutrophils indirectly by activating humoral inflammatory mechanisms, the grain dust extracts were evaluated for their ability to activate the complement system. When incubated with normal human serum, each of the grain dusts caused cleavage of the complement proteins C3 and properdin factor B (PFB). Importantly, the grain dust extracts lead to the generation of C5a, a potent neutrophil chemoattractant generated by complement activation. Since activation of the alveolar macrophage to release chemotactic activity represents an additional indirect mechanism of neutrophil recruitment, an extract from grain sorghum dust was evaluated for its ability to stimulate guinea pig and human alveolar macrophages to release neutrophil chemotactic activity. The results demonstrate that supernatants obtained from alveolar macrophages cultured in the presence of grain sorghum dust extract possessed increased chemotactic activity compared to controls (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Biomechanical Phenomena↗