Christian P. Sommerhoff

Magnetic resonance imaging of congenital heart disease: Sensitivity and specificity using receiver operating characteristic curve analysis

MRI has shown promise for the evaluation of various congenital heart lesions. The current study was designed to assess the sensitivity and specificity of the technique for the evaluation of all major anatomic elements of the heart affected in simple and complex congenital heart disease. MR images of 51 patients (31 males and 20 females, ages 3 to 69 years) with a total of 110 congenital heart lesions were reviewed by a panel of two cardiac radiologists and one pediatric cardiologist, who assessed the cardiac pathoanatomy without knowledge of clinical details and assigned a confidence level to each diagnosis. The true diagnosis was established independently by the findings of angiocardiography and catheterization as well as by surgery, where applicable. ROC curves were generated from the responses, and the sensitivity at a specificity level of 90% was determined. MRI was shown to have a high sensitivity in evaluating great vessel relationships (100%), thoracic aorta abnormalities (94%), ASDs (91%) and VSDs (100%), visceroatrial situs (100%), and loop (100%). Three of five anomalies of the pulmonary and systemic veins were diagnosed by MRI. Right ventricular outflow obstructions (95%) were detected with a much higher sensitivity than lesions of the other valves (aortic valve 52%, mitral valve 62%, tricuspid valve 76%). Spin-echo MRI is a sensitive and specific method for the noninvasive assessment of congenital heart disease, with limitations in the evaluation of some valvular anomalies.

Inhibition of human neutrophil elastase by ICI 200,355

To examine the pathogenetic role of neutrophil elastase in airway hypersecretion, we have studied the novel inhibitor of this enzyme, [4-(4-bromophenylsulfonylcarbamoyl)benzoyl-L-valyl-L-proline 1 (RS)-(1-trifluroacetyl-2-methylprolyl)amide] (ICI 200, 355). This compound was a potent (Ki = 0.6 +/- 0.22 nM) inhibitor of human neutrophil elastase and a much weaker inhibitor of other hydrolases. ICI 200,355 also inhibited the ongoing destruction of insoluble elastin by human neutrophil elastase. ICI 200,355 produced a concentration-dependent inhibition of the secretory response induced by human neutrophil elastase (10(-8) M), with an IC50 of 1.6 x 10(-8) M. ICI 200,355 had no effect on baseline secretion or on the secretory response to chymase, cathepsin G or Pseudomonas aeruginosa elastase. Thus, ICI 200,355 appears to be a useful tool for investigating the role of human neutrophil elastase in inflammatory disorders associated with hypersecretion, such as cystic fibrosis, chronic bronchitis, and asthma.

Synthesis and secretion of an albumin-like protein by cultured bovine tracheal gland serous cells

Bovine tracheal submucosal gland serous cells were incubated with (35S) methionine. The proteins synthesized and secreted into the culture medium during pulse and chase periods were analyzed. Three major protein bands with apparent molecular weight values of 67 kD, 47 kD and 32 kD were detected by fluorography following SDS-polyacrylamide gel electrophoresis. Based on the molecular weight, immuno-reactive cross reactivity and surface molecular change characteristics, the labeled Mr 67 kD protein was identified as an albumin-like protein. Our results suggest that albumin found in airway secretions can originate, at least in part, from tracheal gland serous cells.

Functional and morphologic characterization of mast cells recovered by bronchoalveolar lavage from Basenji greyhound and mongrel dogs

Mast cells are believed to play an important role in the pathogenesis of asthma, and several investigators have suggested that increased numbers of mast cells in the airway lumen or increased releasability of histamine from these mast cells are responsible for chronic airway hyperreactivity. To determine whether mast cells in the lumen of the airways of hyperreactive Basenji greyhound (BG) dogs differ from those of mongrel dogs with normal airway reactivity, we investigated the morphologic and functional characteristics of mast cells recovered by bronchoalveolar lavage (BAL). BAL was performed in five BG and five mongrel dogs with 900 cc of a buffered salt solution. The recovered lavage fluid contained 115 +/- 19 X 10(6) and 116 +/- 14 X 10(6) (mean +/- SEM) cells in BG and mongrel dogs, respectively. The proportion of all mast cells within the recovered cell population as enumerated after fixation with basic lead acetate and staining with alcian blue was not different in BG and mongrel dogs and averaged 0.80 +/- 0.07% and 1.1 +/- 0.3%, respectively. Typical mast cells as identified after fixation with paraformaldehyde were rare; however, significantly more mast cells were found in mongrel (0.03 +/- 0.009%) than in BG dogs (0.004 +/- 0.002%; p less than 0.02). Mast cells recovered from BG and mongrel dogs were not different in their low spontaneous histamine release (2.0 +/- 0.5% and 2.9 +/- 0.8%), their histamine release on stimulation with the calcium ionophore A23187 (maximum release 44.8 +/- 5.7% and 41.5 +/- 3.9%), and their lack of response to compound 48/80 (maximum release 5.8 +/- 1.8% and 6.1 +/- 6.0%).(ABSTRACT TRUNCATED AT 250 WORDS)

Studies of tracheal secretion using serous cell cultures and monoclonal antibodies

The glycoconjugate composition of tracheal secretions varies with physiological and pathophysiological parameters. Believing that these differences might be explained by metabolic or regulatory modifications of particular cell types, we have developed strategies for biochemical analysis at the cellular level. We have produced monoclonal antibodies whose determinants are restricted to a single secretory cell type (serous, mucous, or goblet cell granules, or ciliated cell glycocalyx). By enzyme immunoassay (ELISA), we have characterized four of the antibodies biochemically, and have also used the antibodies as quantitative molecular probes to detect release of antigen from mixed cell explants. Four of the antigens are carried by carbohydrate moieties of high molecular weight glycoproteins. Western blot analysis shows their molecular weight in reducing gels (SDS-PAGE) to exceed 200 kD. When used in parallel with pulse-chase labeling studies, the antibodies are both more sensitive and specific (than bound radioactivity) in detecting gland or goblet cell secretion in response to autonomic drugs or proteases. We have also isolated and cultured serous gland cells for physiological and biochemical studies. These cells express serous cell phenotype as reflected by ultrastructure, histochemistry, and lysozyme activity. Biochemical analysis of their secretory products reveals glycoconjugate components which are heterogeneous with respect to both molecular weight and charge. Radiolabeled secretory products eluting in the void volume of Sepharose C1 4B were completely degraded by chondroitinase ABC. This indicates that the major glycoconjugate produced by serous cell is a proteoglycan resembling chondroitin sulfate.

Effect of inhibitors on histamine release from mast cells recovered by bronchoalveolar lavage in Basenji-Greyhound and Mongrel dogs

Studies of rodent mast cells have demonstrated that subpopulations differ in regard to their response to inhibitors of histamine release. To determine whether such compounds have different effects on mast cells from Basenji-Greyhound (BG) dogs with airway hyperreactivity and from mongrel dogs, we investigated the effect of cromolyn sodium, nedocromil sodium, theophylline, and quercetin on calcium ionophore A23187-induced histamine release from mast cells recovered by bronchoalveolar lavage. Mast cells recovered from BG and mongrel dogs were similar in respect to morphology and spontaneous and calcium ionophore-induce histamine release. Histamine release from mast cells from both BG and mongrel dogs was inhibited by quercetin (10−4M) and nedocromil sodium (5×10−5M). In contrast, only the histamine release from mast cells recoverd from mongrel dogs was inhibited by cromolyn sodium (10−4M) and theophylline (5×10−3M). Thus, mast cells that are similar in regard to morphology and response to histamine liberators may differ in their response to inhibitors of histamine release.