Effects of chemical mediators of anaphylaxis on ciliary function

We assessed the effects of selected chemical mediators of anaphylaxis on CBF in vitro. Ciliated epithelial cells were obtained from the trachea of conscious sheep with a cytology brush and suspended in a perfusion chamber containing KH. Ciliary activity was viewed microscopically and recorded on videotape for subsequent slow-motion analysis of CBF. Prostaglandin E1 (10(-8) M to 10(-6) M), prostaglandin E2 (10(-10) M to 10(-6) M), and leukotriene-C4 (10(-8) M) increased CBF between 7% and 33%. Histamine caused ciliostimulation only at the relatively high concentrations above 10(-5) M (7% increase in CBF), whereas prostaglandin F2 alpha (10(-10) M and 10(-6) M) was without effect. In no preparation was ciliary discoordination observed. These findings indicate that several chemical mediators of anaphylaxis stimulate CBF and that the previously described impairment of mucociliary transport in stable allergic asthma or antigen-induced bronchoconstriction is probably not caused by a primary alteration of ciliary function.     

Airway responses to antigen challenge in allergic rhinitis and allergic asthma

The density dependence of the maximum expiratory flow-volume curve, functional residual capacity (FRC), and specific airway conductance (SGaw) were determined before and during bronchial provocation with ragweed extract in 27 subjects with ragweed hypersensitivity and a history of either bronchial asthma (16 subjects) or allergic rhinitis (11 subjects). Mean baseline SGaw was significantly lower while mean volume of isoflow (Visov) and FrC were significantly higher in subjects with bronchial asthma. During antigen challenge, 10 of 16 subjects with bronchial asthma (63%) and five of 11 subjects with allergic rhinitis (45%) showed a greater than 35% decrease in SGaw ("reactors"): mean relative decreases in SGaw from baseline were 46% and 53%, respectively. The remaining subjects showed a less than 35% decrease in SGaw ("nonreactors") with mean relative decreases of 9% (allergic asthma) and 6% (allergic rhinitis). Mean Visov increased in all subjects with bronchial asthma and in eight of 11 subjects with allergic rhinitis. A significant increase in FRC (6%) was seen only in the "reactors" with bronchial asthma. Following antigen challenge, the beta adrenergic agonist, isoetharine, increased SGaw and decreased Visov. We conclude that in asymptomatic subjects with ragweed hypersensitivity, (1) central and peripheral airway function is more abnormal in subjects with bronchial asthma than in subjects with allergic rhinitis, (2) subjects of both groups show quantitatively and qualitatively comparable airway responses during antigen challenge with a decrease in SGaw or an increase in Visov, possibly representing increase in central and/or peripheral airflow resistance, respectively, (3) Visov may be a more sensitive indicator of airway response to antigen challenge than SGaw, and (4) the bronchodilator effects of a beta adrenergic agonist on antigen-induced bronchospasm are similar in both groups.     

A method for large-scale, high-yield isolation of canine pancreatic islets of Langerhans

A modified collagenase digestion method is described for the isolation of large numbers of islets from the canine pancreas (approximately 3,500 islets/g). The islets isolated by this technique remained viable and released insulin in response to secretagogues after one week of maintenance in tissue culture. Islets isolated from a single donor pancreas were re-implanted into the spleen of the same animal made diabetic by subtotal pancreatectomy and two injections fo streptozotocin. Hyperglycemia was corrected in two dogs and decreased in a third dog followed for 30 days. The islet isolation method is described, therefore, provides a sufficiently large yield of viable islets from one donor pancreas to correct or improve diabetes in a recipient animal.     

Complete abolition of the reentrant supraventricular tachycardia zone using a new modality of cardiac pacing with simultaneous atrioventricular stimulation

In an attempt to prevent recurrent reentrant supraventricular tachycardia, an experimentally designed new pacemaker has been developed. The pacemaker, when connected to both atrial and ventricular electrodes, is capable of sensing either an atrial or ventricular signal and, in turn, triggers simultaneous atrioventricular (A-V) stimulation. Efficacy of this pacemaker was tested in four patients with recurrent paroxysmal A-V nodal reentrant tachycardia during electrpphysiologic studies. After connection of the electrodes to the new pacemaker, all atrial or ventricular premature stimuli elicited simultaneous A-V stimulation with resultant impulse collision in the A-V junction. Consequently, the reentrant tachycardia zone was completely abolished in all patients. This study has thus demonstrated the clinical feasibility of simultaneous A-V pacing to abolish the supraventricular tachycardia zone in man.