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Biomedical subjects

F M Baroody

Publications and source records attributed to F M Baroody.

64 records · Page 4Linked to original sources
PubMed1993

Reflex activation of nasal secretion by unilateral inhalation of cold dry air.

Exposure to cold dry air induces rhinorrhea and other nasal symptoms in many persons. To evaluate whether this response involves a neurogenic component, we delivered a unilateral cold dry air (UniCDA) nasal challenge to volunteers with previously documented reactivity to cold dry air. We measured their nasal secretory responses bilaterally using small filter paper discs to absorb secretions from the nasal mucosa. UniCDA increased nasal secretion both ipsilateral (p < 0.001) and contralateral (p < 0.001) to the challenge when compared with control challenge. Topical atropine (0.225 mg), a muscarinic antagonist, inhibited ipsilateral secretion (p < 0.002) when given ipsilateral to UniCDA. When atropine was given contralateral to UniCDA, there was a trend toward reduction of contralateral secretion but no effect on ipsilateral secretion. Topical anesthesia with lidocaine given ipsilateral to UniCDA inhibited ipsilateral (p < 0.02) and contralateral (p < 0.05) secretion immediately after challenge. Topical anesthesia did not inhibit methacholine-induced nasal secretion. Thus, UniCDA stimulates reflex secretion both ipsilateral and contralateral to challenge which is inhibitable by interrupting either the efferent or the afferent arm of the reflex arc. This human in vivo model supports the importance of neural mechanisms in airway responsiveness to an environmental stimulus.

Adult↗
PubMed1993

Coronal CT scan abnormalities in children with chronic sinusitis.

Coronal computed tomography (CT) scans are currently the optimal study to display the normal and abnormal anatomy in children with chronic and recurrent acute sinusitis after failure of medical therapy. To assess the extent and distribution of disease as well as associated anatomic abnormalities in this pediatric population, 74 coronal CT scans of children with continued symptoms of sinusitis after failure of extensive medical therapy were reviewed retrospectively. Twelve children with cystic fibrosis showed the characteristic features of medial displacement of the lateral nasal wall in the middle meatus and uncinate process demineralization, creating the appearance of a maxillary sinus mucocele. Nine of these 12 children had increased attenuation in the maxillary sinus on soft-tissue windows. In the remaining 62 children, a significantly greater frequency of disease, when compared with that reported for adults, was seen in the maxillary, anterior ethmoid, posterior ethmoid, and frontal sinuses. Children with asthma (n = 33) had more extensive disease. Bony anatomic abnormalities were similar to those reported for adults, except for a lower incidence of septal deformity.

Acute Disease↗
PubMed1993

Inflammatory diseases of the sinuses: an overview of immunology.

We have provided an overview of the immune system and its components. These components--cell-mediated and humoral immunity, the complement system and the different phagocytic cells--all function in concert to protect the body from foreign invaders. When this powerful immune system behaves in a misdirected fashion, however, disease states develop from its injurious effects. One such disease process, intimately related to sinus disease, is allergic rhinitis, which starts as an IgE-mediated response and evolves into an extensive reaction with the contribution of several inflammatory cells and mediators (Fig. 5).

Antibody Formation↗
PubMed1992

Histamine-containing cells obtained from the nose hours after antigen challenge have functional and phenotypic characteristics of basophils.

The pattern of mediators and appearance of cells that stain with alcian blue during human experimental early and late phase allergic reactions suggest that basophils accumulate in nasal secretions within hours of local Ag stimulation. To further explore whether the histamine containing cells that enter the nose after Ag challenge are mast cells or basophils, we studied their functional and phenotypic characteristics. Approximately 24 h after intranasal Ag provocation of subjects with allergic rhinitis, nasal lavage was performed, and the cells were isolated for degranulation studies, analysis of surface Ag, and viability. The average histamine content per alcian blue staining cell was 0.78 +/- 0.2 pg (n = 7), similar to that reported for peripheral blood basophils. Nasal cells were challenged in vitro with anti-IgE, ragweed Amb a I, and FMLP and their responses were compared to those of peripheral blood basophils isolated simultaneously from the same donors. Nasal leukocytes released histamine maximally at 0.1 micrograms/ml of anti-IgE (35.8 +/- 7.8%, n = 7) and responded to FMLP (25.4 +/- 9.9%, n = 7). The response of the cells to ragweed Amb a I and anti-IgE was attenuated compared to peripheral blood basophils. Anti-IgE-induced histamine release was calcium and temperature dependent. Dual color immunofluorescence and flow cytometric analysis of the recovered nasal cells coexpressed CD18, a leukocyte marker not expressed by mast cells. The nasal cells consistently had high levels of spontaneous histamine release (19.5 +/- 2.0%, n = 22). The viability of all cells, assessed by erythrosin B dye exclusion, was 70 +/- 2% (n = 15). However, the viability of IgE-bearing cells was only 28.3 +/- 5.7% (n = 4). The characteristics of histamine release and the nature of the cellular surface markers provide functional proof that the histamine-containing cells accumulating after nasal Ag challenge are basophils and not mast cells.

Adult↗
PubMed1992

Response of nasal mucosa to histamine or methacholine challenge: use of a quantitative method to examine the modulatory effects of atropine and ipratropium bromide.

We have developed a new technique for the direct local administration of test solutions to the nasal mucosa and for quantification of nasal secretory responses. This technique, a variation on several published reports of filter paper use, allows simple and rapid determination of drug effects and facilitates the analysis of ipsilateral and contralateral responses to local challenge of the nasal mucosa. We have used this technique to investigate the secretory responses of the nasal mucosa to methacholine and histamine and to determine the effects of atropine and ipratropium bromide (Atrovent nasal spray) on these secretory responses.

Atropine↗
PubMed1992

Ipratropium bromide (Atrovent nasal spray) reduces the nasal response to methacholine.

We investigated the efficacy of local ipratropium bromide on methacholine-induced nasal secretions in a double-blind, placebo-controlled experiment. Twenty subjects with perennial rhinitis received a total intranasal dose of 21, 42, 84, and 168 micrograms of ipratropium bromide or placebo in each nostril. One hour later, filter paper disks were used to deliver increasing doses of methacholine and to collect secretions from the left septum. Concomitantly, symptoms of rhinorrhea and nasal congestion were scored. Compared with doses of placebo, all doses of ipratropium bromide significantly reduced the methacholine-induced increase in nasal secretion weights and symptoms of rhinorrhea (p less than 0.01). The highest dose was significantly more effective than the lower doses in reducing secretion weights (p = 0.01). We speculate that ipratropium bromide may prove beneficial for the treatment of rhinorrhea in perennial rhinitis. Furthermore, increasing the delivered dose to 168 micrograms may increase efficacy without augmenting side effects.

Adult↗
PubMed1992

Intranasal beclomethasone inhibits antigen-induced nasal hyperresponsiveness to histamine.

To determine whether intranasal steroid treatment inhibits the increased sensitivity to histamine that occurs 24 hours after nasal antigen challenge, 12 allergic volunteers were entered into a double-blind study comparing placebo or 164 micrograms of beclomethasone dipropionate twice a day for 7 days. Beclomethasone dipropionate partially reduced the early mediator response to antigen and the influx of eosinophils 24 hours later. Comparing the initial histamine challenge with that done 24 hours after antigen with the subjects on placebo, there was a significant increase in sneezes, TAME-esterase activity, and albumin. Pretreatment with intranasal beclomethasone dipropionate resulted in a reduced response to histamine 24 hours after antigen challenge. A positive correlation occurred between the number of eosinophils in the lavage before histamine challenge and the level of TAME-esterase activity (rs = 0.67, p = 0.03) during the histamine challenge that followed antigen with the subjects on placebo. We thus confirmed the increase in nonspecific nasal airway responsiveness 24 hours after antigen challenge, with a concomitant increase in eosinophils, and demonstrate its inhibition by pretreatment with intranasal steroids.

Administration, Intranasal↗
PubMed1991

The role of leukotrienes in allergic rhinitis: a review.

Leukotrienes are potent proinflammatory mediators. Our understanding of their role in allergic rhinitis has increased, but further, extensive investigation is required. The sulfidopeptide LTs are generated during the immediate response to antigen provocation and are probably increased during the late inflammatory phase and during seasonal exposure. The source of LTC4 in the early allergic reaction includes the mast cell, but other cell types may also contribute. LTD4 causes nasal congestion and increased blood flow, but not sneezing or significant rhinorrhea. Studies in which LT generation was pharmacologically reduced support a role for these mediators in allergic rhinitis. There is now a need to evaluate the more potent, recently developed, LT antagonists in rhinitis. These agents should help establish the relative importance of LTs to the many other inflammatory mediators that are implicated in the pathogenesis of allergic rhinitis. Such knowledge will broaden and improve our choice of therapeutic modalities for this disease.

Humans↗
PubMedDate not supplied

Elevation of nasal mucosal temperature increases the ability of the nose to warm and humidify air.

The nose functions to warm and humidify inspired air. The factors that influence these functions have been studied to a limited degree. We have developed a method for measuring the temperature and relative humidity of the air before and after nasal conditioning to study nasal function. In this experiment we studied the effects of raising the mucosal surface temperature by immersion of the feet in warm water. Six subjects (avg. age = 27.0 years) were randomized to immersion of the feet in 30 degrees C and 40 degrees C water. The nasal mucosal temperature increased significantly from the 32.2+/-1.3 degrees C during immersion in the 30 degrees C water to the 33.1+/-1.2 degrees C during immersion in 40 degrees water (p < 0.05). No significant difference in nasal volume was noted between the 30 degrees (17.8+/-4.5 cc) and the 40 degrees (17.7+/-5.3 cc) immersions. There was a significant increase in the conditioning capacity of the nose (as measured by total water content of inspired air) in response to cold-air challenge during the 40 degrees immersion (1669+/-312 mg water) when compared to the 30 degrees immersion (1324+/-152 mg water). From these data we deduce that warming of the nasal mucosa improves the ability of the nose to condition inspired air without a significant change in the volume of the nasal cavity.

Acoustics↗