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Biomedical subjects

J M Drazen

Publications and source records attributed to J M Drazen.

At least 127 records · Page 7Linked to original sources
PubMed1996

Effects of interleukin 5-induced pulmonary eosinophilia on airway reactivity in the guinea pig.

Administration of interleukin 5 (IL-5) to guinea pigs by tracheal injection was associated with increased recovery of eosinophils and neutrophils from bronchoalveolar lavage (BAL) fluid. The number of eosinophils recovered from BAL fluid increased in a dose-dependent manner from 9 +/- 2 X 10(3)/ml to a plateau of 143 +/- 29 X 10(3)/ml after the administration of recombinant human IL-5 (rhIL-5). Tracheal administration of recombinant guinea pig IL-5 (gpIL-5) also increased eosinophil recovery but was less potent than rhIL-5. Histological analysis confirmed the presence of inflammatory cells in the lung; there were higher grades of inflammation in airway than in parenchymal tissue after gpIL-5 administration. In addition, the histological grade of airway inflammation was greater 24 and 72 h after gpIL-5 administration than it was 6 days after administration. Airway hyperresponsiveness is reported to occur in guinea pigs exposed to rhIL-5 by intraperitoneal cellular production. It is surprising that airway infiltration with eosinophils induced by the topical application of IL-5 was not associated with hyperresponsiveness to substance P, histamine, or platelet-activating factor in intact animals or to methacholine in tracheally perfused lungs. Furthermore, the microvascular leakage induced by substance P was not altered by rhIL-5 administration. These findings indicate that the presence of eosinophils alone is not sufficient for the expression of airway hyperresponsiveness. Our ability to separate eosinophil recruitment and retention in the tissues from airway hyperresponsiveness indicates that these two processes are distinct and that the presence of eosinophils in lung tissue, by itself, is not sufficient to alter airway contractile responses.

Animals↗
PubMed1996

Production and characterization of guinea pig IL-5 in baculovirus-infected insect cells.

To study the role interleukin (IL)-5 may play in altering airway function in asthma, we have produced recombinant protein for exogenous administration to guinea pigs. The guinea pig IL-5 (gpIL-5) cDNA was cloned by polymerase chain reaction (PCR) amplification of guinea pig spleen RNA and expressed as a secretion product from recombinant baculovirus-infected Sf9 insect cell cultures. The protein was purified to homogeneity by a four-step procedure that included immunoaffinity chromatography using polyclonal antipeptide antibodies against a region of the mature secreted cytokine. The cytokine was properly processed after the signal sequence by the Sf9 cells, was glycosylated with terminal mannose-containing oligosaccharide, and had proper disulfide-linked dimer structure as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified preparation was active in vitro and in vivo as determined by its ability to prime human basophils to release leukotriene C4 in the presence of C5a and to induce airway eosinophilia in naive guinea pigs.

Animals↗
PubMed1996

Prostaglandin G/H synthase-2 is the constitutive and dominant isoform in cultured human lung epithelial cells.

Two isoforms of prostaglandin G/H synthase (PGHS; prostaglandin endoperoxide synthase, cyclooxygenase) have been identified; PGHS-1 is expressed constitutively in most tissues, whereas PGHS-2 is thought to be induced by various proinflammatory cytokines and growth factors. In this study, we determined which isoform of PGHS mRNA, protein, and activity was present constitutively in A549 (a human lung adenocarcinoma cell line) and in untransformed (normal human bronchial epithelial or NHBE) and transformed (16HBE4o-) human bronchial epithelial cells. Two PGHS-2-specific inhibitors, NS-398 and L-745, 337, blocked the release of prostaglandin E2 from A549 cells with mean inhibitory concentrations of 5 and 18 nM, respectively, but did not inhibit its release from human bronchial smooth muscle cells (BSMC) at a concentration of 10 microM. Northern and immunoblot analysis demonstrated that BSMC expressed PGHS-1 mRNA and protein constitutively, whereas epithelial cells expressed PGHS-2 mRNA and protein constitutively with either undetectable (A549, 16HBE4o-) or very low levels (NHBE) of PGHS-1. We conclude that PGHS-2 is the dominant PGHS isoform in unstimulated and stimulated lung epithelial cells in culture.

Base Sequence↗
PubMed1996

Acute histamine-induced flux of airway liquid: role of neuropeptides.

The role of capsaicin-sensitive neuropeptides in the accumulation of airway wall liquid observed 30 s after histamine infusion was investigated in guinea pigs. Two groups were studied: normal animals and animals in which endogenous neuropeptides had been depleted by capsaicin pretreatment. A rapid intravenous infusion of saline or histamine (11 micrograms/kg resulted in marked but similar changes in pulmonary mechanics in normal and capsaicin-pretreated animals. To assess liquid accumulation in airway wall compartments, the lungs were frozen 30 s after histamine infusion; airways from these lungs, 0.15-2.44 mm in internal perimeter, were imaged by low-temperature scanning electron microscopy. There was no difference in average airway surface liquid thickness (hASL) in normal or capsaicin-pretreated airways in response to saline. In capsaicin-pretreated animals, histamine infusion was associated with a significantly decreased hASL (hASL, cap11/hASL,cap0 = 0.58, P < 0.04). Capsaicin pretreatment, without histamine exposure, caused significant increases in epithelial and submucosal areas (Aepi,cap0/Aepi,norm0 = 1.23, P < 0.06; Asub,cap0/Asub,norm0 = 1.40, P < 0.01). The notation cap0 and cap11 indicates capsaicin-pretreated airways given 0 or 11 micrograms/kg histamine, respectively; similarly, norm0 and norm11 indicate normal airways given 0 and 11 micrograms/kg histamine, respectively. Histamine infusion in capsaicin-pretreated animals was associated with liquid shifts from epithelium to lamina propria and from submucosa to adventitia; however, the total wall area was similar to, if not smaller than, that in capsaicin-pretreated animals without histamine treatment. In contrast, histamine infusion in normal animals resulted in significant increases in the areas of the epithelial and lamina propria compartments (Aepi,norm11/Aepi,norm0 = 1.25, P < 0.05; Alp,norm11/Alp,norm0 = 2.19, P < 0.001) as well as a substantial increase in adventitial area, which was significantly attenuated by capsaicin pretreatment (Aadv,cap11/Aadv,norm11 = 0.40, P < 0.001). The resulting total wall area was more than twice that in normal animals without histamine treatment. Our data indicate that histamine-induced accumulation of liquid in the epithelium, lamina propria, and adventitia of normal airways is rapid in onset, most likely derives from a leaky bronchial microvasculature, and is mediated by the secondary release of neurokinins.

Airway Resistance↗
PubMed1996

Elevated nitric oxide concentrations in isolated lower airway gas of asthmatic subjects.

Previous studies have raised the possibility that the measurement of nitric oxide (NO.) concentrations in expired air may represent a noninvasive measure of lower airway inflammation. To address the question of whether the elevated NO. recovered in mixed expired air from asthmatic subjects is a reflection of the pulmonary airway microenvironment or merely nasopharyngeal contamination, mixed expired NO. determinations were performed in five normal and five asthmatic subjects before and after orotracheal intubation (thereby isolating the lower airway gas from ambient air contamination or gas conditioned in the nasopharynx). The mixed expired NO. concentrations determined in patients with asthma were significantly elevated (p < 0.05 or less) above those of normal subjects in both the pre- and postintubation samples. After intubation, mixed expired NO. levels were 4.7 +/- 1.3 ppb and 13.2 +/- 2.0 ppb in normal and asthmatic individuals, respectively; the difference in these values was statistically significant (p < 0.01). Lower airway gas, sampled through the bronchoscope during a breathhold, was found to contain NO. concentrations of 7.0 +/- 1.2 ppb and 40.5 +/- 5.6 ppb at the tracheal carina of normal and asthmatic individuals, respectively. The asthmatic values were significantly (p < 0.01) elevated above those found in normal subjects. These findings indicate that the difference in mixed expired NO. of normal subjects and asthmatics reflects a difference in NO. concentration present in the lower airway.

Adult↗
PubMed1996

Urinary leukotriene E4 levels increase upon exposure to hypobaric hypoxia.

STUDY OBJECTIVE: To determine whether urinary leukotriene E4 (uLTE4) levels increase upon exposure to high altitude, and also to ascertain the relationship between uLTE4 levels and symptoms of acute mountain sickness (AMS). DESIGN: Prospective, unblinded, single-factor (altitude) experimental study. SETTINGS: US Army research laboratory facilities at sea level ([SL] 50 m), 1,830 m, and 4,300 m. PARTICIPANTS: Eight healthy male subjects ranging in age from 19 to 24 years. MEASUREMENTS: uLTE4 levels and symptoms of AMS were measured at just above SL (50 m), 3 1/2 days after being transported from SL to moderate altitude (MA) (1,830 m), and 1 1/2 days after ascent from 1,830 to 4,300 m (high altitude [HA]). Symptoms of AMS were assessed using standard indexes derived from the Environmental Symptoms Questionnaire weighted toward cerebral (AMS-C) and respiratory (AMS-R) manifestations. Oxygen saturation was measured noninvasively by pulse oximetry at SL and HA. RESULTS: The mean (+/-SEM) uLTE4 levels (pg/mg creatinine) were 67.9 (+/-13.2) at SL; 82.3 (+/-5.5) at MA; and 134.8 (+/-19.4) at HA (p < 0.05 comparing HA with SL and MA). CONCLUSIONS: We conclude that uLTE4 levels increase shortly after exposure to HA even after staging for 4 days at MA. Although this study does not clearly demonstrate a relationship between uLTE4 levels and symptoms of AMS, it supports the hypothesis that leukotrienes may be involved in the pathophysiologic state of AMS.

Adult↗
PubMed1995

Constitutive and allergen-induced expression of eotaxin mRNA in the guinea pig lung.

Eotaxin is a member of the C-C family of chemokines and is related during antigen challenge in a guinea pig model of allergic airway inflammation (asthma). Consistent with its putative role in eosinophilic inflammation, eotaxin induces the selective infiltration of eosinophils when injected into the lung and skin. Using a guinea pig lung cDNA library, we have cloned full-length eotaxin cDNA. The cDNA encodes a protein of 96 amino acids, including a putative 23-amino acid hydrophobic leader sequence, followed by 73 amino acids composing the mature active eotaxin protein. The protein-coding region of this cDNA is 73, 71, 50, and 48% identical in nucleic acid sequence to those of human macrophage chemoattractant protein (MCP) 3, MCP-1, macrophage inflammatory protein (MIP) 1 alpha, and RANTES, respectively. Analysis of genomic DNA suggested that there is a single eotaxin gene in guinea pig which is apparently conserved in mice. High constitutive levels of eotaxin mRNA expression were observed in the lung, while the intestines, stomach, spleen, liver, heart, thymus, testes, and kidney expressed lower levels. To determine if eotaxin mRNA levels are elevated during allergen-induced eosinophilic airway inflammation, ovalbumin (OVA)-sensitized guinea pigs were challenged with aerosolized antigen. Compared with the lungs from saline-challenged animals, eotaxin mRNA levels increased sixfold within 3 h and returned to baseline by 6 h. Thus, eotaxin mRNA levels are increased in response to allergen challenge during the late phase response. The identification of constitutive eotaxin mRNA expression in multiple tissues suggests that in addition to regulating airway eosinophilia, eotaxin is likely to be involved in eosinophil recruitment into other tissues as well as in baseline tissue homing.

Allergens↗
PubMed1995

Diurnal variation of urinary leukotriene E4 and histamine excretion rates in normal subjects and patients with mild-to-moderate asthma.

BACKGROUND: Leukotriene E4 (LTE4) and histamine excreted into the urine reflect the in vivo synthesis and release of cysteinyl leukotrienes and histamine, respectively. We examined the diurnal variation of the excretion rate of these mediators over 4 consecutive days in normal subjects (n = 5) and patients with stable mild-to-moderate asthma (n = 8). METHODS: Sixteen consecutive 6-hour urine samples were collected over 4 days. Urinary LTE4 concentrations were determined by reverse-phase high-pressure liquid chromatography, followed by ELISA. Urinary histamine concentrations were measured by ELISA. The excretion rates of these compounds were normalized relative to urinary creatinine content. RESULTS: The mean urinary LTE4 excretion rate was 83.8 +/- 38.2 pg/mg creatinine (mean +/- SD) in normal subjects; in patients with asthma, the urinary LTE4 excretion rate (110.0 +/- 59.2 pg/mg creatinine) was significantly higher than that in normal subjects (p < 0.05). The urinary histamine excretion rate was not different between normal subjects (24.0 +/- 12.5 ng/mg creatinine) and patients with asthma (31.5 +/- 25.8 ng/mg creatinine). A robust and systematic within-day variation (p < 0.01), but no day-to-day variation, was observed in histamine excretion rate. Although the magnitude of variation in LTE4 excretion within a day was significantly greater in patients with asthma than in normal subjects (p < 0.05), we could not identify any specific diurnal variation pattern in either the normal or the asthma group. No significant correlation was observed between urinary LTE4 and histamine excretion rate within any subject. CONCLUSIONS: Patients with asthma excrete LTE4 in the urine at a greater rate than normal subjects. Although no systematic variation in urinary LTE4 excretion rates over the course of a day was observed in either normal subjects or patients with stable asthma, the presence of a systematic diurnal variation of urinary histamine excretion exists in both groups.

Adult↗
PubMed1995

Quantitative locus analysis of airway hyperresponsiveness in A/J and C57BL/6J mice.

Airway hyperresponsiveness is a key characteristic of human asthma and a marker for asthma-like conditions in animals. F1 mice derived from A/J and C57BL/6J display a phenotype which resembles the asthma-like phenotype of the A/J mice. Since airway responsiveness failed to segregate as a mendelian trait, we show significant linkage at two loci, Bhr1 (lod = 3.0) and Bhr2 (lod = 3.7) on chromosomes 2 and 15. A third locus, Bhr3 (lod = 2.83), maps to chromosome 17. Each of these loci maps near candidate loci implicated in the pathobiology of asthma. Our study represents the first linkages established through a genome-wide survey of airway hyperresponsiveness in any mammal.

Analysis of Variance↗
PubMed1995

Chemical regulation of pulmonary airway tone.

Over the past three years, substantial progress has been made in dissecting out the role of each of these individual effector systems, namely, the leukotrienes, neuropeptides, and nitrogen oxides. The next major challenge is to understand how they function in an integrated fashion.

Airway Resistance↗
PubMed1995

Substance P-induced histamine release in tracheally perfused guinea pig lungs.

The capacity of substance P (SP) and endogenously released tachykinins to liberate histamine was examined in isolated tracheally perfused guinea pig lungs. Increasing doses of tracheally injected SP were associated with the recovery of increasing amounts of histamine from lung effluent. The mechanism of SP-induced histamine liberation was explored in studies with neurokinin-(NK) receptor agonists and antagonists. Tracheal injection of either the NK1 agonist [Sar9,Met(O2)11]SP or the NK2 agonist [beta-Ala8]-neurokinin A-(4-10) was associated with a significant increase in histamine recovery from lung effluent. In addition, both the NK1 antagonist CP-99994 and the NK2 antagonist SR-48968 significantly inhibited SP-induced histamine release. These findings support the hypothesis that SP can liberate histamine from guinea pigs lungs by a mechanism that depends predominantly on NK1- and NK2-receptor activation. The liberation of endogenous tachykinins by acute tracheal injection of capsaicin was also associated with augmented histamine recovery, which was inhibited by combined NK1- and NK2-receptor blockade. Tracheal injection of SP was associated with an increase in the percentage of airway mast cells exhibiting histological evidence of degranulation. This study demonstrates that exogenous SP, as well as endogenous tachykinins released from capsaicin-sensitive neurons, can liberate histamine, most likely from airway mast cells, by a mechanism that depends predominantly on the activation of NK1 and NK2 receptors.

Animals↗
PubMed1995

Neuropeptide content of lungs from asthmatic and nonasthmatic patients.

Tracheal and lung parenchymal SP-LI (substance P-like immunoreactivity) and VIP-LI (vasoactive intestinal peptide-like immunoreactivity) content was measured in HPLC-purified tissue extracts from patients with and without asthma. We detected significantly less SP-LI in tracheal tissue from asthmatic than from nonasthmatic patients, whereas parenchymal SP-LI content was not significantly different between these groups. This finding does not support the concept that asthmatic lungs contain excessive amounts of SP. Indeed, lower SP-LI content of tracheal tissues from asthmatic patients may reflect augmented SP release followed by degradation. We detected greater quantities of VIP-LI in tracheal than in parenchymal tissue in both groups, but did not detect significant differences in VIP-LI content in tracheal or parenchymal tissues from asthmatic and nonasthmatic patients. These findings indicate that asthmatic and nonasthmatic lungs contain similar levels of VIP.

Adolescent↗
PubMed1995

Inflammatory effector mechanisms in asthma.

Each of these effector systems has the capacity to initiate airway obstruction or alter airway responsiveness in asthma. It is likely that they act in concert in certain asthmatic settings. Further basic and applied research will define their relative roles in asthma.

Arachidonate 5-Lipoxygenase↗