Biomedical subjects

F M Baroody

Publications and source records attributed to F M Baroody.

At least 37 records · Page 2Linked to original sources

PubMed1999

Relationship between histamine and physiological changes during the early response to nasal antigen provocation.

To investigate the temporal relationships of mediator release and physiological changes during the early response to allergen, we challenged allergic individuals intranasally with antigen and followed their responses. This was done by using small filter paper disks to challenge one nostril and collect secretions from both the challenged and the contralateral nostril, thus enabling us to evaluate the nasonasal reflex. There was a significant increase in sneezing after allergen challenge that peaked within 2 min and returned to baseline. The weights of nasal secretions as well as nasal symptoms increased immediately and remained significantly elevated for 20 min in both nostrils. Nasal airway resistance increased slowly, reaching its peak at approximately 6 min after challenge on the ipsilateral side, but it did not change on the contralateral side. Histamine levels peaked 30 s after removal of the allergen disk on the side of challenge, whereas albumin levels peaked after those of histamine. Lactoferrin paralleled the increase in secretion weights and occurred in both nostrils. Increasing doses of antigen produced dose-dependent increases in all parameters, whereas control challenges produced no response. These studies describe a human model for the evaluation of the allergic response that is capable of simultaneously measuring mediator release and the physiological response, including the nasonasal reflex. This model should prove useful in studying the mechanism of allergic rhinitis in humans.

Adult↗

PubMed1999

A technique to measure the ability of the human nose to warm and humidify air.

To assess the ability of the nose to warm and humidify inhaled air, we developed a nasopharyngeal probe and measured the temperature and humidity of air exiting the nasal cavity. We delivered cold, dry air (19-1 degrees C, <10% relative humidity) or hot, humid air (37 degrees C, >90% relative humidity) to the nose via a nasal mask at flow rates of 5, 10, and 20 l/min. We used a water gradient across the nose (water content in nasopharynx minus water content of delivered air) to assess nasal function. We studied the characteristics of nasal air conditioning in 22 asymptomatic, seasonally allergic subjects (out of their allergy season) and 11 nonallergic normal subjects. Inhalation of hot, humid air at increasingly higher flow rates had little effect on both the relative humidity and the temperature of air in the nasopharynx. In both groups, increasing the flow of cold, dry air lowered both the temperature and the water content of the inspired air measured in the nasopharynx, although the relative humidity remained at 100%. Water gradient values obtained during cold dry air challenges on separate days showed reproducibility in both allergic and nonallergic subjects. After exposure to cold, dry air, the water gradient was significantly lower in allergic than in nonallergic subjects (1,430 +/- 45 vs. 1,718 +/- 141 mg; P = 0.02), suggesting an impairment in their ability to warm and humidify inhaled air.

Adult↗

PubMed1999

Comparison of the response to histamine challenge of the nose and the maxillary sinus: effect of loratadine.

To study the response of the maxillary sinus to histamine provocation, we performed a double-blind, randomized, crossover trial during which nonallergic subjects without symptoms of rhinitis (n = 25) received either 10 mg loratadine or placebo once daily for a week and then underwent nasal challenge with histamine (3, 10, and 30 mg/ml) followed, 24 h later, by a maxillary sinus challenge while still receiving the medication. Nasal challenge with histamine led to significant increases in vascular permeability, reflex nasal secretions, sneezing, and other nasal symptoms. Sinus challenge resulted in significant increases in vascular permeability within the sinus cavity (P < 0.01) and some nasal symptoms but no significant change in reflex nasal secretions. The response of the sinus mucosa to histamine was lower in magnitude than that of the nose. Treatment with loratadine resulted in a significant inhibition of the histamine-induced changes in both nasal and sinus cavities. Our data suggest the lack of a sinonasal reflex response to histamine provocation of the maxillary sinus of nonallergic individuals.

Adult↗

PubMed1998

Intranasal beclomethasone reduces allergen-induced symptoms and superficial mucosal eosinophilia without affecting submucosal inflammation.

Previous investigations have suggested that nasal secretions, obtained by lavage or scraping, and the nasal submucosa, sampled by biopsy, are two distinct compartments. We investigated the effect of intranasal corticosteroids on antigen-induced eosinophil influx into both compartments. We performed a double-blind, placebo-controlled study in 15 patients with seasonal allergic rhinitis. Beclomethasone dipropionate, 84 microg twice a day, was delivered to one nostril while the other nostril received placebo for 1 wk. Subjects were then challenged with grass or ragweed extracts on each inferior turbinate. Nasal scrapings from both inferior turbinates were obtained before and 24 h after challenge, and bilateral inferior turbinate biopsies were obtained 24 h after challenge, with the subjects still receiving treatment. Intranasal steroids led to a significant reduction in sneezes and eosinophil influx in nasal secretions without affecting the number of eosinophils in the submucosa. Furthermore, intranasal steroids had no effect on the numbers of submucosal EG2+ (activated eosinophils) or CD25+ (IL-2-receptor-bearing) cells, nor did they decrease the endothelial expression of vascular cell adhesion molecule-1 (VCAM-1). These data show that pretreatment with intranasal steroids successfully inhibited the clinical response to allergen and reduced eosinophils in the superficial compartment of the nasal mucosa, but it had no effect on inflammation in the deeper compartment. This might be related to a different distribution of the active medication and antigen into the nasal mucosa or to a specific effect of the active medication on the epithelium resulting in inhibited migration of eosinophils across this layer.

Administration, Intranasal↗

PubMed1997

Ragweed allergic rhinitis and the paranasal sinuses. A computed tomographic study.

OBJECTIVE: To explore the potential association of allergic rhinitis and sinusitis. DESIGN: Prospective clinical trial. SETTING: Academic tertiary referral center. PARTICIPANTS: Ten subjects with symptomatic ragweed allergy during the peak of the ragweed season. MAIN OUTCOME MEASURES: We obtained a paranasal sinus computed tomographic scan on all volunteers and had them complete a modified Rhinitis Quality of Life Questionnaire. All subjects were then treated with intranasal aqueous beclomethasone dipropionate (168 micrograms twice a day) and completed the Rhinitis Quality of Life Questionnaire weekly until the end of the study. RESULTS: Six of 10 of the subjects had sinus mucosal thickening on computed tomographic scan. All subjects improved symptomatically. A second computed tomographic scan was obtained after the pollen season in 5 patients with mucosal abnormalities, while the patients continued treatment with intranasal steroids and symptomatically improved. The sinus mucosal abnormalities persisted in all patients. CONCLUSION: Despite the 60% incidence of abnormalities on the computed tomographic scans of the subjects with ragweed allergy during the season, these abnormalities appear, at most, to contribute minimally to the patient's symptoms, since resolution of symptoms was not accompanied by a reduction in sinus mucosal abnormalities.

Administration, Inhalation↗

PubMed1997

Effect of enantiomeric forms of albuterol on stimulated secretion of granular protein from human eosinophils.

We studied the effect of R-, S- and R,S-albuterol in inhibiting the eosinophil peroxidase (EPO) secretion caused by 10(-10) to 10(-6) M formyl-met-leu-phe + 5 micrograms/ml cytochalasin B (FMLP/CB) in non-allergic and allergic subjects. Total RAST score obtained for allergic subjects was 4.12 +/- 0.21 vs 0.36 +/- 0.17 for non-allergic subjects (P < 0.0001). Stimulated EPO secretion was comparable in allergic [2,051 +/- 567 ng/10(6) eosinophils (eos)] and non-allergic subjects [2,337 +/- 488 ng/10(6) eos (P = NS)]. At all concentrations used, both R- and R,S-enantiomers caused comparable (27-32%) inhibition of FMLP/CB stimulated secretion of EPO in allergic and non-allergic subjects. Pretreatment with S-albuterol caused no augmentation of EPO secretion in either allergic (115 +/- 34.6%) or non-allergic subjects (114 +/- 23.7%) subjects, and there was no significant difference in secretion caused by FMLP/CB alone in either experimental group. Similar results were obtained for subjects stratified according to serum IgE concentration. Our data demonstrate that both R- and R,S-albuterol are equivalently effective in inhibiting stimulated secretion of EPO in both normal and allergic subjects and that there is no paradoxical augmenting effect of S-albuterol in stimulated eosinophil secretion.

Adrenergic beta-Agonists↗

PubMed1997

Nasal provocation with allergen induces a secondary serum IgE antibody response.

The study of the IgE response to seasonal antigen exposure is limited by its occurrence once a year and by the variability of patient exposure to pollens. To overcome these problems, we investigated whether nasal challenge with antigen causes an increase in serum anti-ragweed IgE levels. We challenged individuals with ragweed allergy intranasally with nanogram quantities of ragweed antigen extract and measured their serum anti-ragweed IgE levels before and at weekly intervals after challenge. In a series of studies we found that there was a reproducible rise in antigen-specific serum IgE levels beginning the first week after challenge that plateaued at about 180% of baseline levels during the fourth week and remained elevated for 8 weeks. Not all individuals showed this response. The magnitude of the allergen-specific IgE response to nasal challenge appeared to be greater than the response to seasonal exposure. Treatment with intranasal beclomethasone before challenge did not affect the response. The results demonstrate a human in vivo model for the study of the antigen-specific secondary IgE response to allergen.

Administration, Intranasal↗

PubMed1997

Total IgE serum levels correlate with sinus mucosal thickness on computerized tomography scans.

BACKGROUND: Sinusitis involves an inflammatory response with similarities to asthma. OBJECTIVE: We sought to determine whether a correlation exists between total IgE and the sinus mucosal thickening as assessed by computed tomography (CT) scans. METHODS: We screened the charts of 300 otolaryngology patients who had total and specific serum IgE determinations in 1994 and from this group selected all patients who had also undergone a sinus CT scan close to the time of serum evaluation (n = 86). Severity of disease on CT scan was graded by two investigators blinded to IgE levels. RESULTS: There was a significant positive correlation between severity of disease on CT scans and IgE (r[s] = 0.37, p = 0.0007). Furthermore, patients with a more advanced disease stage had higher IgE levels. There was also a positive correlation between severity of disease and the sum of specific IgE grades (r[s] = 0.29, p = 0.007). CONCLUSION: The data suggest that IgE levels or a linked genetic parameter may contribute to the mucosal inflammation in the paranasal sinuses.

Adolescent↗

PubMed1997

Treatment with hot, humid air reduces the nasal response to allergen challenge.

Ten subjects with asymptomatic seasonal allergy, outside of their allergy season, underwent allergen provocation following 1 hour of exposure to air at either 20 degrees C and 30% relative humidity (RH) or air at 37 degrees C and 90% RH. The ipsilateral changes following antigen challenge were compared under the two conditions. Conditioning of the nose to 37 degrees C, 90% RH reduced total histamine release (7.9 +/- 1.8 ng vs 4.2 +/- 1.3 ng; p < or = 0.05), sneezes (6 +/- 2 vs 3 +/- 1; p < or = 0.05), pruritus (score of 17.4 +/- 6.0 vs score of 2.0 +/- 1.8 out of a total score of 100, p < or = 0.01), nasal airway resistance (1.4 +/- 0.8 kPa/L/sec vs 0.2 +/- 0.1 kPa/L/sec; p < or = 0.05), human serum albumin levels (389.6 +/- 53.4 micrograms vs 242.2 +/- 37.9 micrograms; p < or = 0.05), and congestion (score of 23.8 +/- 4.8 vs score of 10.6 +/- 5.4 out of a total score of 100, p < or = 0.01). It had no effect on the volume of secretions (p = 0.8), lactoferrin levels (p = 0.3), or rhinorrhea (p = 1.0). Thus air at 37 degrees C and 90% RH partially reduces the early response to antigen. Its effects are greatest on histamine release, the vascular response, and neural responses, with no effect on the glandular response. The mechanisms underlying these effects are unknown.

Adult↗

PubMed1997

Low dose clemastine inhibits sneezing and rhinorrhea during the early nasal allergic reaction.

BACKGROUND: Clemastine (1 mg) is currently available over-the-counter for the treatment of allergic rhinitis. OBJECTIVE: To evaluate the efficacy of half the standard dose of clemastine (0.5 mg) in inhibiting the nasal response to allergen and the cutaneous response to histamine. METHODS: Double-blind, placebo-controlled, crossover study of 20 allergic subjects out of season. The subjects received placebo or clemastine administered one, four, and six hours before the challenges. Filter paper discs were used both to challenge the nasal mucosa with diluent and allergen and collect generated secretions. Sneezes, secretion weights, nasal and ocular symptoms, and albumin levels in nasal secretions were monitored for the nasal challenge. Intradermal skin testing was performed with diluent followed by histamine and the wheal and flare reactions were measured. RESULTS: There was a significant reduction in the number of sneezes after clemastine administered one, four, and six hours prior to challenge compared with placebo (P < .01). Clemastine administered four and six hours before challenge reduced sneezing significantly more than clemastine administered one hour before challenge (P < .05). Antigen-induced increases in secretion weights and symptoms of rhinorrhea were significantly reduced compared with placebo only when clemastine was administered four and six hours prior to challenge (P < .05). Pretreatment with clemastine had no significant inhibitory effects on other nasal symptoms or on albumin levels in nasal secretions, an objective index of increased vascular permeability. Pretreatment with clemastine did not inhibit the histamine-induced wheal skin reaction but showed a tendency, when administered six hours prior to the intradermal challenge, to reduce the flare reaction induced by the lowest dose of histamine (P = .05). CONCLUSIONS: The data show that clemastine, given at half the usual dose four and six hours prior to allergen challenge, provides relief for sneezing and rhinorrhea and suggests that this dose might be useful in the treatment of allergic rhinitis.

Adult↗

PubMed1997

Bilateral increases in histamine after unilateral nasal allergen challenge.

Studying the inflammatory response that follows the early response to nasal challenge with antigen provides a better understanding of allergic rhinitis than just studying the immediate (early) response. Nine allergic volunteers were challenged unilaterally with antigen-containing discs, and bilateral changes in physiologic responses as well as in the concentration of histamine in nasal secretions were measured for 11 h. We found significant immediate increases in symptoms, sneezes, ipsilateral nasal airway resistance, and ipsilateral histamine in the early phase response. Two-thirds of the allergen-challenged volunteers showed increases in physiologic parameters or histamine in the hours after allergen challenge. The pooled data of all subjects exhibited significant increases in bilateral nasal airway resistance and in ipsilateral and contralateral histamine, hours after unilateral provocation. These responses differed significantly from control subjects. In another group of 11 volunteers challenged ipsilaterally with antigen, the number of basophils increased both on the side of challenge and on the contralateral side. The magnitude of the increase on the ipsilateral side correlated with the increase on the contralateral side (r(s) = 0.72). The basophils are the most likely source of the contralateral increase in histamine as they are on the ipsilateral side. Although the mechanisms underlying this contralateral increase in basophils and histamine are not known, we speculate that delayed, neurogenic responses play a contributory role.

Adult↗

PubMed1996

Effects of loratadine and terfenadine on the induced nasal allergic reaction.

OBJECTIVE: To evaluate the effect of terfenadine and loratadine on the early nasal allergic response to challenge and the subsequent cellular influx and hyperresponsiveness. DESIGN: Double-blind, placebo-controlled, triple-crossover study. SUBJECTS: Fourteen, asymptomatic, allergic volunteers. INTERVENTIONS: After an initial challenge with methacholine chloride, subjects received treatment with placebo, loratadine (10 mg by mouth daily), or terfenadine (60 mg by mouth twice daily) for 1 week, followed by a nasal allergen challenge with lavages; 24 hours later, while the subjects were still receiving medication, the quantity of cells in the nasal lavage was determined, and another challenge with methacholine was done. Mediator levels were quantified in the nasal lavages after the allergen c hallenge, and the weight of the methacholine-induced nasal secretions was measured. RESULTS: Both loratadine and terfenadine treatment resulted in significant reductions in allergen-induced sneezing and the levels of histamine, kinins, albumin, and N-alpha-tosyl-L-arginine methyl ester-esterase activity in recovered nasal lavages compared with the reductions that resulted from placebo treatment, with no significant difference among the treatments. Treatment had no effect on the levels of tryptase, prostaglandin D2 or leukotriene C4. A significant eosinophil influx into nasal secretions 24 hours after the allergen challenge in patients who were receiving placebo (P=.006) was not affected by loratidine or terfenadine treatment. Comparing methacholine-induced secretions between screening challenges and challenges with the patients who were being treated with either loratadine or terfenadine, there was a significant decrease in secretions after the use of these antihistamines (P<.05). CONCLUSION: Both loratadine and terfenadine partially inhibit the early nasal response to allergen challenge and the subsequent reactivity to a challenge with methacholine without affecting the influx of eosinophils into nasal secretions.

Adult↗

PubMed1996

Duration of action of intranasal atropine on methacholine-induced nasal secretions.

OBJECTIVE: To evaluate the duration of the inhibitory action of intranasal atropine on the secretory response to nasal challenge with methacholine. DESIGN: Double-blind, placebo-controlled, four-way crossover trial. SUBJECTS: Twelve volunteers with perennial allergic rhinitis. INTERVENTIONS: Subjects were treated intranasally with placebo or 100, 200, and 400 micrograms of atropine in each nostril. They were then challenged 30 minutes after administration of the nasal spray and hourly for 6 hours with 0.19 mg of methacholine. The weight of nasal secretions generated by methacholine challenge served as an indicator of the secretory response. The nasal challenges and the collection of nasal secretions were performed using filter paper disks. RESULTS: After placebo treatment, the response to methacholine was similar at each time point. In contrast, all doses of atropine significantly reduced the response to methacholine stimulation at the 30-minute, 1-hour, and 2-hour time points. CONCLUSIONS: Our data show that the anticholinergic activity of intranasal atropine lasts at least 2 hours with no significant difference in the duration of inhibitory action between the doses used. The results suggest that intranasal atropine could become a therapeutic modality for patients in whom glandular hypersecretion is a major symptom.

Administration, Intranasal↗

PubMed1996

Polysomnography in the evaluation of readiness for decannulation in children.

OBJECTIVE: To determine whether polysomnography is useful in the evaluation of readiness for decannulation in children with long-term tracheotomy. DESIGN: Descriptive, retrospective case series. SETTING: Tertiary care pediatric center, pediatric sleep disorders laboratory, and pediatric otolaryngology referral center. PATIENTS: Children (younger than 18 years) with tracheotomy undergoing polysomnography to assess their dependence on tracheotomy. INTERVENTION: Polysomnography in all patients; endoscopy and decannulation in those judged clinically ready. MAIN OUTCOME MEASURES: Success of decannulation. RESULTS: Thirteen of 16 patients with favorable polysomnographic data were successfully decannulated. CONCLUSION: Polysomnography is a useful supplement to airway endoscopy in the evaluation of readiness for decannulation in children with long-term tracheotomy and dynamic airway issues.

Child↗

PubMed1996

CD4+ lymphocytes are increased in the sinus mucosa of children with chronic sinusitis.

OBJECTIVES: To quantitate lymphocyte subtypes in sinus tissues harvested from children with chronic sinusitis and coexisting asthma, allergies, and cystic fibrosis during functional endoscopic sinus surgery and compare them with those in normal adult sphenoid sinus mucosa. DESIGN: Immunohistochemical staining of surgical specimens with monoclonal antibodies against CD4 and CD8 surface antigens. SETTING: Tertiary medical center. PATIENTS: Thirty-two children who underwent functional endoscopic sinus surgery for chronic sinusitis refractory to medical treatment (median age, 8 years; range, 2-13 years) were divided into 3 groups: 10 with asthma, 15 without asthma, and 7 with cystic fibrosis. Sphenoid sinus mucosa obtained from 10 adults (median age, 70 years) undergoing transsphenoidal hypophysectomy was used as control tissue. MAIN OUTCOME MEASURES: Numbers of CD4+ and CD8+ cells in the lamina propria and epithelium of surgical specimens. RESULTS: Significantly more CD4+ cells were in the sinus mucosa of patients with chronic sinusitis than in the normal sinus mucosa (P < .01), but there was no significant difference in the number of CD8+ cells (P = 4). Patients with chronic sinusitis with asthma, without asthma, and with cystic fibrosis all had increased numbers of CD4+ cells compared with sphenoid mucosa, with the difference reaching statistical significance only in the subgroup with chronic sinusitis without asthma (P < .001). The numbers of CD4+ cells were higher in patients with chronic sinusitis than in the sphenoid mucosa irrespective of allergic status. Significantly more CD4+ than CD8+ cells were in tissues from the patients with chronic sinusitis irrespective of concomitant diseases or allergic status. CD4+ and CD8+ cells were more numerous in the apical portion of the submucosa (immediately beneath the epithelium) than in the basal portion both in patients with chronic sinusitis and in normal sphenoid tissue. CONCLUSIONS: Children with chronic sinusitis have predominance of CD4+ cells in the sinus mucosa as compared with normal sphenoid tissue. This contrasts with published results in adults with chromic sinusitis, in whom CD8+ cells predominate in nasal polyps and the submucosa, possibly reflecting a difference in the immunologic response of children and adults.

Adolescent↗

PubMed1996

Polysomnography after adenotonsillectomy in mild pediatric obstructive sleep apnea.

OBJECTIVES: a) To determine the need for intensive monitoring on the first operative night of surgery in children undergoing adenotonsillectomy for mild obstructive sleep apnea; b) to examine the effect of narcotics on postoperative obstructive sleep apnea. DESIGN: Randomized, prospective study. SETTING: University hospital. PATIENTS: Children, ranging in age between 1 and 18 yrs, presented to the Pediatric Otolaryngology Clinic for adenotonsillectomy for mild obstructive sleep apnea defined as from one to 15 obstructive apnea events per hour on preoperative polysomnogram. INTERVENTIONS: Patients were assigned to receive either a narcotic- or a halothane-based anesthetic for adenotonsillectomy. A postoperative polysomnogram was performed in the pediatric intensive care unit on the first operative night. MEASUREMENTS AND MAIN RESULTS: Eighteen patients were recruited, 15 of whom met inclusion criteria: nine patients received a halothane-based anesthetic and six patients received a fentanyl-based anesthetic. When the data were analyzed by pooling both groups, the differences between pre- and postoperative sleep studies demonstrated a reduction in the number of obstructive events and less severe oxygen desaturations on the operative night. Total sleep time between the two sleep studies decreased from 371 +/- 13 to 304 +/- 14 mins. The number of obstructive apnea events/hr decreased as well. The lowest oxygen saturation measured during rapid eye movement sleep was 78 +/- 5% preoperatively and 92 +/- 1% postoperatively. CONCLUSIONS: Our data suggest that children without underlying medical conditions, neuromotor diseases, or carniofacial abnormalities, 1 to 18 yrs of age, who suffer from mild obstructive sleep apnea, have improvements documented by polysomnography on the night of surgery following adenotonsillectomy and do not necessarily need to be monitored intensively. These findings were not significantly affected by the choice of intraoperative anesthetic.

Adenoidectomy↗

PubMed1996

Pediatric tracheobronchial foreign bodies: historical review from the Johns Hopkins Hospital.

We investigated changing trends in pediatric tracheobronchial foreign body removal and resident experience from 1939 to 1991. We retrieved the records of 234 cases of tracheobronchial foreign body removal at Johns Hopkins. The mean number of cases per year was 5.9. The most common foreign bodies removed were peanuts, accounting for 38.9%. The average yearly incidence of pediatric tracheobronchial foreign bodies remained relatively constant during the period studied. Our data suggested little change in outcome or complications with the advent of optical telescopes in the mid-1970s, despite their great value in improved visualization. Resident experience and training were evaluated by the number of cases attended by each resident during his or her training. The number varied from 1 to 8 cases, not including experience acquired at our sister institutions. Although complete data could not be obtained in many of the older medical records, our review suggests that despite the advantage offered by the optical forceps technology, proper training and experience in traditional rigid endoscopic techniques is still crucial to optimize outcome and minimize the risk of complications in pediatric tracheobronchial foreign body removal. Chevalier Jackson's recommendation that residency training include an animal laboratory course in foreign body removal still applies.

Adolescent↗

PubMed1996

Unilateral nasal allergen challenge leads to bilateral release of prostaglandin D2.

BACKGROUND: Multiple mediators including prostaglandin D2 and leukotriene B4 have been shown to increase in nasal secretions during the early response to nasal challenge with antigen. OBJECTIVE: Our objective was to investigate the time course of prostanoid and leukotriene B4 release into nasal secretions on both the ipsilateral and contralateral side after a unilateral nasal allergen challenge. METHODS: We performed a controlled, randomized trial. Six volunteers were challenged unilaterally with antigen or diluent in a randomized order and discs were used to collect nasal secretions from both nostrils at 2 min intervals for 20 min after the challenge. Prostanoids and leukotriene B4 (LTB4) in recovered nasal secretions were measured by combined capillary gas chromatography-negative ion chemical ionization mass spectrometry (GC/MS). RESULTS: Nasal allergen challenge resulted in a significant and immediate increase in symptoms and sneezing. PGD2 was significantly elevated above diluent values (0.6 +/- 0.6 pg) 30 s after removal of the allergen disc (P < 0.05), reached its peak (423.2 +/- 182.4 pg) at 2 min and then slowly decreased. PGD2 also increased on the contralateral side after unilateral allergen challenge, reaching peak values about six times lower than on the ipsilateral side (70.8 +/- 21.7 pg at 6 min). Levels of 9a, 11b-PGF2 after antigen provocation became significantly higher than after diluent (0 +/- 0 pg) on the ipsilateral side at 2 min (17.2 +/- 5.9 pg), and reached peak levels at 4 min (25.1 +/- 8.0 pg). LTB4 also increased significantly on the side of challenge. For the other prostanoids measured (PGF2, PGF2 alpha, TxB2, 6kPGF1 alpha), no significant changes in either ipsilateral or contralateral secretions were observed after allergen challenge. CONCLUSIONS: Our study described the kinetics of PGD2 and LTB4 release as well as the contralateral release of PGD2.

Adult↗