Thyroid transcription factor-1 (TTF-1) deficiency syndrome is characterized by neurologic, thyroidal, and pulmonary dysfunction. Children usually have mild-to-severe respiratory symptoms and occasionally die of respiratory failure. Herein, we describe an infant with a constitutional 14q12-21.3 haploid deletion encompassing the TTF-1 gene locus who had cerebral dysgenesis, thyroidal dysfunction, and respiratory insufficiency. The clinical course was notable for mild hyaline membrane disease, continuous ventilatory support, and symmetrically distributed pulmonary cysts by imaging. He developed pneumonia and respiratory failure and died at 8 months. Pathologically, the lungs had grossly visible emphysematous changes with "cysts" up to 2 mm in diameter. The airway generations and radial alveolar count were diminished. In addition to acute bacterial pneumonia, there was focally alveolar septal fibrosis, pneumocyte hypertrophy, and clusters of airspace macrophages. Ultrastructurally, type II pneumocytes had numerous lamellar bodies, and alveolar spaces contained fragments of type II pneumocytes and extruded lamellar bodies. Although immunoreactivity for surfactant protein SP-A and ABCA3 was diminished, that for SP-B and proSP-C was robust, although irregularly distributed, corresponding to the distribution of type II pneumocytes. Immunoreactivity for TTF-1 protein was readily detected. In summation, we document abnormal airway and alveolar morphogenesis and altered expression of surfactant-associated proteins, which may explain the respiratory difficulties encountered in TTF-1 haploinsufficiency. These findings are consistent with experimental evidence documenting the important role of TTF-1 in pulmonary morphogenesis and surfactant metabolism.

Activated charcoal given through a nasogastric tube is a standard intervention for many types of toxic ingestions in the emergency department. This case study describes a teenage girl whose multidrug overdose was complicated by accidental charcoal instillation into her left lung and pleural space through a misplaced nasogastric tube. The ensuing empyema did not respond to antibiotic therapy alone, probably due to the inherent properties of charcoal, and required a chest tube placement with continuous irrigation. Unlike previously reported cases, this patient did well clinically, without long‐term morbidity. Pediatr Pulmonol. 2003; 35:490–493. © 2003 Wiley‐Liss, Inc.

We tested the hypothesis that mechanical plasticity of airway smooth muscle may be mediated in part by the p38 mitogen-activated protein (MAP) kinase pathway. Bovine tracheal smooth muscle (TSM) strips were mounted in a muscle bath and set to their optimal length, where the active force was maximal (F(o)). Each strip was then contracted isotonically (at 0.32 F(o)) with ACh (maintained at 10(-4) M) and allowed to shorten for 180 min, by which time shortening was completed and the static equilibrium length was established. To simulate the action of breathing, we then superimposed on this steady distending force a sinusoidal force fluctuation with zero mean, at a frequency of 0.2 Hz, and measured incremental changes in muscle length. We found that TSM strips incubated in 10 microM SB-203580-HCl, an inhibitor of the p38 MAP kinase pathway, demonstrated a greater degree of fluctuation-driven lengthening than did control strips, and upon removal of the force fluctuations they remained at a greater length. We also found that the force fluctuations themselves activated the p38 MAP kinase pathway. These findings are consistent with the hypothesis that inhibition of the p38 MAP kinase pathway destabilizes muscle length during physiological loading.

To explore the possibility that protein kinase C (PKC) participates in desensitization to Ca(2+)-mobilizing hormones in MDCK cells, we measured intracellular free Ca2+ concentration ([Ca2+]i) using fura-2 and video microscopy. We first examined the response of MDCK cells grown on plastic dishes. Exposure of cells to bradykinin (BK) or to carbachol, followed by reexposure after washing off the hormone, revealed two features of hormone desensitization. First, the initial hormone-induced peak response of [Ca2+]i was transitory; [Ca2+]i returned to control levels despite continued presence of hormone. Second, cells remained refractory to hormone rechallenge for 5 min after washing off hormone; [Ca2+]i response on re-exposure was reduced 70% compared with initial hormone-stimulated peak. Subsequent experiments demonstrated involvement of PKC in both desensitization processes. Pretreatment with the phorbol ester, phorbol 12-myristate 13-acetate, significantly blunted initial response to BK and to carbachol by 70 and 86%, respectively. When hormone-stimulated C kinase activity was enhanced with the diglyceride lipase inhibitor, RG 80267, BK- and carbachol-induced increases in [Ca2+]i were blunted 50%. Pretreatment with sphingosine, an inhibitor of PKC, resulted in an amplification of initial hormone-stimulated increase in [Ca2+]i and restored the response to rechallenge. To examine the possible interaction between BK and carbachol,both of which use PKC to induce desensitization, we measured [Ca2+]i in cells grown as monolayers on permeable, collagen-coated supports. Both carbachol and BK induced desensitization to the other hormone (heterologous desensitization)provided that the two hormones were applied to the same side of the polarized monolayer (apical).(ABSTRACT TRUNCATED AT 250 WORDS)

We investigated the role of protein kinase C (PKC) in mediating carbachol's stimulation of transepithelial Cl- secretion in T84 cells. Direct PKC activation with phorbol 12-myristate 13-acetate (PMA) stimulated transepithelial Cl- transport (measured as the short-circuit current), demonstrating that PKC could interact with the secretory apparatus. Carbachol stimulated PKC activity, suggesting that the enzyme might participate in the hormone's action. Diacylglycerol metabolism inhibitors (DMIs), known to augment hormone-stimulated increases in diacylglycerol levels, potentiated the short-circuit current response to carbachol. The effect of DMIs was not due to amplification of carbachol-induced increases in PKC activity, however; PKC activity during carbachol stimulation was no higher in the presence of DMIs than in their absence. Augmentation of carbachol's action by DMIs appeared to be due to the direct activation of PKC which, like PMA, stimulated the Cl- conductance of the apical membrane (GCl). The effects of DMIs and carbachol on GCl were additive. Carbachol itself stimulated GCl but not by activating PKC; staurosporine did not blunt the effect of carbachol on GCl. Nor did staurosporine reduce the effect of carbachol on transepithelial Cl- secretion. These observations demonstrate that PKC does not participate in the secretory action of carbachol in T84 cells and suggest that direct PKC activation with DMIs and PMA stimulates an apical pool of PKC that is not accessible to carbachol applied to the basolateral membrane.

To examine the role of calcium in mediating carbachol's action in secretory epithelia, we simultaneously measured intracellular free [Ca] [( Ca]i) and transepithelial chloride transport in T84 cells grown on collagen-coated filters. [Ca]i was measured with fura-2 and fluorescence microscopy and expressed as a relative value [( Ca]'i) normalized to control. Chloride transport was measured as the short-circuit current (Isc) with a voltage clamp. Monolayers were pretreated with cyclic AMP to augment the response of Isc to carbachol, a procedure that did not qualitatively change the response of the monolayer to carbachol. The carbachol-induced changes in Isc appeared to be dependent on the increase in [Ca]i. First, carbachol caused both Isc and [Ca]'i to increase in parallel. Isc increased from 32 +/- 5 to 70 +/- 9 microA and then declined to 57 +/- 16 microA while [Ca]'i increased from 72 +/- 14 to 156 +/- 22 nM and then declined to 133 +/- 45 nM. Second, the carbachol-induced increases in Isc and [Ca]'i were correlated. The greater the hormone-stimulated rise in [Ca]'i, the higher the increase in Isc. Third, carbachol's stimulation of Isc was blunted by preventing the calcium spike with the cellular calcium buffer 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetra-acetic acid (BAPTA). Although the carbachol-induced increase in [Ca]'i appeared necessary for the increase in Isc, it was not clear if carbachol's action was solely the result of an increase in [Ca]'i. Increasing [Ca]'i with ionomycin, although causing Isc and [Ca]'i to increase in parallel, failed to increase Isc to the levels observed with carbachol. These experiments suggest that although the carbachol-induced increase in Isc is dependent on the increase in [Ca]i, the hormone may activate a second process that increases the sensitivity of the calcium-activated transport process to changes in [Ca]i.