Assessment of Lung Structure and Regional Function Using 0.55 T MRI in Patients With Lymphangioleiomyomatosis.

OBJECTIVES: Contemporary lower-field magnetic resonance imaging (MRI) may offer advantages for lung imaging by virtue of the improved field homogeneity. The aim of this study was to evaluate the utility of lower-field MRI for combined morphologic imaging and regional lung function assessment. We evaluate low-field MRI in patients with lymphangioleiomyomatosis (LAM), a rare lung disease associated with parenchymal cysts and respiratory failure. MATERIALS AND METHODS: We performed lung imaging on a prototype low-field (0.55 T) MRI system in 65 patients with LAM. T2-weighted imaging was used for assessment of lung morphology and to derive cyst scores, the percent of lung parenchyma occupied by cysts. Regional lung function was assessed using oxygen-enhanced MRI with breath-held ultrashort echo time imaging and inhaled 100% oxygen as a T1-shortening MR contrast agent. Measurements of percent signal enhancement from oxygen inhalation and percentage of lung with low oxygen enhancement, indicating functional deficits, were correlated with global pulmonary function test measurements taken within 2 days. RESULTS: We were able to image cystic abnormalities using T2-weighted MRI in this patient population and calculate cyst score with strong correlation to computed tomography measurements (R = 0.86, P < 0.0001). Oxygen-enhancement maps demonstrated regional deficits in lung function of patients with LAM. Heterogeneity of oxygen enhancement between cysts was observed within individual patients. The percent low-enhancement regions showed modest, but significant, correlation with FEV1 (R = -0.37, P = 0.007), FEV1/FVC (R = -0.33, P = 0.02), and cyst score (R = 0.40, P = 0.02). The measured arterial blood ΔT1 between normoxia and hyperoxia, used as a surrogate for dissolved oxygen in blood, correlated with DLCO (R = -0.28, P = 0.03). CONCLUSIONS: Using high-performance 0.55 T MRI, we were able to perform simultaneous imaging of pulmonary structure and regional function in patients with LAM.

Immunoglobulin E to staphylococcal and streptococcal toxins in patients with chronic sinusitis/nasal polyposis.

BACKGROUND: The role of infectious agents and their contribution to the inflammation in chronic sinusitis/nasal polyposis (CS/NP) is not clear. Staphylococcal and streptococcal toxins have superantigen activity and have been implicated in inflammatory conditions such as atopic dermatitis, psoriasis, and asthma. OBJECTIVE: We investigated the presence of immunoglobulin (Ig)E antibodies to staphylococcal and streptococcal toxins in the serum of individuals with CS/NP. METHOD: IgE antibodies to staphylococcal exotoxins, A, B, and toxic shock syndrome toxin-1 and streptococcal pyrogenic exotoxin A, B, and C were measured in 23 individuals with CS/NP before functional endoscopic sinus surgery and in controls (7 atopic and 6 nonatopic) individuals without chronic sinusitis. Presence of IgE to the toxins was also correlated with disease severity on sinus computed tomography (CT) scans. RESULTS: Staphylococcal and streptococcal toxin specific IgE antibodies were detected in 18 of 23 (78%) and 7 of 21 (33.3%) patients, respectively. None of the controls had IgE to the staphylococcal or streptococcal toxins (P <.0001). There was no association between radiographic severity of sinus disease and the presence of IgE antibody to the toxins. CONCLUSION: A significantly greater proportion of CS/NP patients had IgE to staphylococcal or streptococcal toxins. Evidence of IgE antibodies directed against staphylococcal and streptococcal toxins in the sera of patients with CS/NP suggests a potential role of these toxins with established superantigen effects in the pathogenesis of CS/NP.

Amphotericin-induced stridor: a review of stridor, amphotericin preparations, and their immunoregulatory effects.

BACKGROUND: Various adverse effects have been reported with the use of amphotericin B. The respiratory adverse effects include dyspnea, tachypnea, bronchospasm, hemoptysis, and hypoxemia. Stridor has not been previously reported with the use of amphotericin B. OBJECTIVE: To review the mechanism of action and reports of respiratory adverse effects for amphotericin B, the liposomal preparations of amphotericin B, and the differential diagnosis of stridor. DATA SOURCES: A MEDLINE search from 1966 to 2002 was performed to review the current literature for possible mechanisms and immunoregulatory effects related to the infusion of amphotericin B. RESULTS: Amphotericin B has been shown to increase tumor necrosis factor alpha (TNF-alpha) concentrations in macrophages. In addition, it induces prostaglandin E2 synthesis and increases the production of interleukin 1beta (IL-1beta) in mononuclear cells. The immunoregulatory effects of amphotericin B include increases in apoptosis, production of monocyte chemoattractant protein 1, superoxide anion, nitric oxide, and intercellular adhesion molecule 1 expression. CONCLUSIONS: Amphotericin B induces the production of TNF-alpha, interferon-gamma, and IL-1beta, which may potentiate its toxic effects. Some liposomal preparations induced lower levels of TNF-alpha and nitric oxide and may be useful in patients unable to tolerate amphotericin B deoxycholate.