Human lung lysozyme: sources and properties

Lysozyme in human airway secretions is thought to defend the lung against airborne bacteria. Although lysozyme has been purified and characterized from human tears, milk, saliva, and other sources (1-5), human lung lysozyme has received little attention except for measurements of concentrations in sputum (6, 7), immunocytochemical and histochemical localization (8-12),and studies of secretion by alveolar macrophages (13). This study was designed to identify the sources of secreted lung lysozyme, to quantitate the secretory activities of the various sources,and to compare the properties of lysozyme from lung cells with those from other tissues.

Proteinases release mucin from airways goblet cells

The mucin-release effect of proteinases on airways epithelium was assessed in vitro. Using explants of rabbit tracheal mucosa-submucosa we determined that elastase and alkaline proteinase from Pseudomonas aeruginosa, pancreatic trypsin and elastase and the microbial proteinases subtilisin, thermolysin and pronase, all stimulate mucin release from goblet cells. On the other hand Streptomyces caespitosus proteinase pancreatic chymotrypsin and collagenase fail to trigger mucin release. Bovine trachea and human nasal polyp epithelium also release mucins in response to proteinases. Mucin release activity is dependent on proteolytic activity of enzymes which have a fairly broad, but generally similar, substrate specificity. The cellular mechanism of action is not known. We propose that mucin secretion in response to proteinases represents a useful defence mechanism but also forms the basis for hypersecretory states and airways obstruction in chronic endobronchial inflammatory states.

Alteration of sulfation of glycoconjugates, but not sulfate transport and intracellular inorganic sulfate content in cystic fibrosis airway epithelial cells

The secreted and cell surface high molecular weight glyco-conjugates (HMG) generated by primary cultures of airway epithelial cells from cystic fibrosis (CF) patients are oversulfated. To determine whether this abnormality is maintained in transformed CF airway epithelial cells and whether differences in transport or intracellular accumulation of sulfate can explain this alteration, we assessed sulfate metabolism in paired CF and normal cell lines as well as primary cultures of CF and normal cells. Both 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid-inhibitable and -resistant [35S]sulfate efflux and influx were identical for each pair of CF and normal cell lines. Furthermore, cell content of inorganic sulfate was not significantly different in CF and normal cells. However, compared with primary CF cells that oversulfate HMG transformed CF cells oversulfated cell surface HMG but not HMG released into culture medium. Our results suggest that plasma membrane sulfate transport is not altered in CF airway epithelial cells and the abnormal sulfation of HMG may be due to perturbation in intracellular sulfate activation or transfer of activated sulfate to HMG. The relationship of this abnormality to CF transmembrane conductance regulator mutations remains to be determined.

Differential effects of ozone on lung epithelial lining fluid volume and protein content

Urea dilution has been used to estimate the volume of epithelial lining fluid (ELF) in the respiratory tract. However, ELF volume may be overestimated as the result of rapid net diffusion of urea from tissues into the bronchoalveolar lavage (BAL) fluid. This study established a protocol for rat BAL in a manner that minimizes this problem and then used this procedure to examine the edemagenic effects of ozone (O3) exposure on ELF volume and the concentrations of ELF protein and albumin. One passage lavage with variable dwell times up to 30 s showed no difference in recovered urea, protein, and albumin and ELF volume between 0 and 4 s, but a progressive increase of each thereafter. The calculated concentrations of protein and albumin in ELF did not vary significantly with dwell time. By increasing the number of lavage passages from one to three, the amounts of recovered urea, protein, and albumin and estimated ELF volume were increased with each passage. Again, the calculated concentrations of protein and albumin in ELF did not vary appreciably. When a single lavage passage and no added dwell time were used, it was observed that exposure of rats to 2 but not 0.5 and 1 ppm O3 increased urea, protein, and albumin in the BAL immediately after 6 h exposure. In addition, at 18 h postexposure to 1 ppm O3, ELF volume increased only 21%, but protein and albumin concentrations in ELF were 2.3- and 4.5-fold of control values, respectively. A higher O3 concentration (2 ppm) moderately increased ELF volume (+83%) and exerted even greater effects on concentrations of ELF protein (7.8-fold) and albumin (19-fold) while lower O3 dosage (0.5 ppm) had no significant effect. SDS-PAGE analysis showed that small serum proteins including albumin were greatly enriched in lung BAL fluid of 1 ppm O3-exposed rats. These results demonstrate that movement of water and protein into the airspaces after O3 exposure is not strictly coupled, and that protein recovery by BAL should cautiously be used to indicate airspace edema as a result of O3 injury.

Outcome measures for clinical trials in cystic fibrosis. Summary of a Cystic Fibrosis Foundation consensus conference

The CFF Consensus Conference concluded with a summary of those outcome measures that would be most useful in studies of patients 6 years of age and older and those measures that would be most useful in studies of the younger population (< 6 years of age) (Table). These measures were further divided into biologic markers most appropriate for initial (phase I and phase II) clinical trials and those especially useful in large, multicenter (phase III) pivotal trials. There is an ongoing need to improve the accuracy and validity of currently available measures of biologic activity and clinical efficacy in CF, especially in the younger population. The conference participants recommended that the following eight issues be addressed as soon as possible: (1) definition of pulmonary exacerbation, (2) broadly applicable methods of testing pulmonary function in small children (ideally a single test for all ages), (3) a comprehensive severity-of-disease score for young children, (4) reliable methods of quantifying chest x-ray and CT scan changes in young patients, (5) simple, inexpensive measures of lung inflammation, (6) a centralized, uniform approach to the establishment of data monitoring committees, (7) a quality of well-being scale for small children, and (8) reliable, reproducible aerosol delivery systems with defined characteristics. In addition, participants recommended that better methods be developed for assessing patients' adherence to research protocols.

Increased adherence of Staphylococcus aureus from cystic fibrosis lungs to airway epithelial cells

Airway colonization by Staphylococcus aureus is a frequent feature of cystic fibrosis (CF). To assess the pathogenesis of selective colonization with this organism, we compared the capacity of S. aureus isolated from the respiratory tract of CF and non-CF patients to adhere to epithelial cells from the upper and lower airways of CF and control subjects. Bacterial adherence to bronchial epithelial cell lines was significantly greater for CF than for non-CF isolates (p < 0.001). Of 17 CF S. aureus isolates 12 adhered at a level > 1 bacterium per cell; this was true for only 1 of 14 non-CF isolates. CF S. aureus isolates also bound more avidly than non-CF isolates to ciliated (p < 0.05) and squamous nasal cells (p < 0.02) and buccal epithelial cells (p < 0.005) freshly harvested by scraping. Each S. aureus isolate bound with equal avidity to epithelial cells from CF patients and healthy individuals. Adherence was not related to sex, age, severity of pulmonary disease, presence of other microorganisms in the airways, or genotype of the CF hosts. Binding of S. aureus was blocked by proteinase treatment of organisms, suggesting that adherence is mediated by one or more peptide adhesins. We propose that the high prevalence of adherent S. aureus is due either to selection of adherent strains by CF airways or to induction of an adherent phenotype by factors residing at the CF airways surface.

Sulfate concentrations and transport in human bronchial epithelial cells

Inorganic sulfate concentrations in the cytoplasm of human bronchial epithelial cells exceeded levels in the bathing medium under all circumstances tested. Cell sulfate concentrations were directly related to medium sulfate concentrations and inversely related to medium chloride concentrations. In physiological media there was a sulfate compartment of approximately 0.3 mM that exchanged very slowly with extracellular sulfate. In media lacking chloride, sulfate was accumulated by the cells to a level as high as 2 mM. Sulfate uptake was markedly inhibited by external chloride and by stilbene sulfonic acid derivatives but was not affected by sodium in the medium. Efflux of 35SO4(2-) was stimulated by both chloride and sulfate in the bathing medium but inhibited by stilbenes. The following compounds had no effect on sulfate movements: phorbol esters, adenosine 3',5'-cyclic monophosphate derivatives, and okadaic acid. Changes in medium tonicity were likewise without effect. Our results suggest that human bronchial epithelial cells maintain a steady-state disequilibrium for inorganic sulfate. Furthermore, sulfate appears to exist in at least two compartments in the cells: one that is slowly exchangeable with sulfate in the medium and another exchangeable compartment that is of negligible size in physiological media but that becomes very large in media lacking chloride. Sulfate is transported by an anion exchanger of broad specificity that is not influenced by substances known to modulate chloride channels.

Development of mucociliary transport in the postnatal ferret trachea

Little is known of the developmental aspects of mucociliary transport. Previous studies have documented that newborn ferret trachea has very few ciliated cells but numerous immature secretory cells in the epithelium and only rudimentary submucosal glands. Rapid and complete maturation occurs in the first postnatal month. This study examines mucociliary transport during this period of rapid maturation. We made direct observations of particle movement across the epithelium of ferret tracheas. No mucus transport could be demonstrated on the first day of life. Transport was discernible, although sporadic and slow, by 7 days and reached adult levels (10.7 +/- 3.7 mm/min) by 28 postnatal days. The emergence of transport capability correlated well with previously described developmental changes in ciliation, mucus secretion, and ion permeability and transport. Threshold mucus transport occurred at 1 wk of age when 20-25% of the surface cells are ciliated. The neonatal ferret appears to be a useful model for assessing integrated epithelial structure-function relationships that are important not only during early development but also during repair after airway injury involving deciliation.

Cystic fibrosis: a current review

Cystic fibrosis (CF) is the most common severe genetic disorder seen in Caucasians. Defective exocrine gland secretions result in chronic diseases of the respiratory and gastrointestinal systems. However, the CF gene recently has been located and cloned. Currently, genetic technology allows identification of sibling carriers and antenatal diagnosis within families. Oral implications associated with CF include enamel hypoplasia and tooth discoloration, salivary gland involvement, reduced incidence of dental caries, reservoir for potentially pathogenic respiratory bacteria, mouth breathing, and anterior open bite associated with nasal and sinus obstruction. Continued efforts to improve early diagnosis and treatment of CF should increase life expectancy. Affected patients are expected to seek regular dental care more frequently as they learn to view the disease as manageable.

Developmental changes of ferret tracheal mucin composition and biosynthesis

We characterized the chemical composition of mucins secreted by ferret tracheal explants and the activities of key mucin glycosyltransferases in ferret tracheal epithelium during a period of rapid postnatal maturation of the mucin-secreting structures. Ferret tracheal explants secrete three major groups of high molecular weight glycoconjugates: (1) those susceptible to bovine testicular hyaluronidase; (2) those resistant to hyaluronidase and exhibiting high density (p greater than or equal to 1.60 g/mL); and (3) those resistant to hyaluronidase and exhibiting low density (1.45 less than or equal to p less than 1.60 g/mL). The hyaluronidase-resistant, low-density glycoconjugates have typical mucin properties and constitute 36% of total glycoconjugates released in newborns but only 8% in adult ferrets. Mucin secretory rate per unit surface area of trachea progressively decreases with age. Mucin amino acid and total carbohydrate contents do not vary; however, the sialic acid content increases, and fucose content as well as blood group A activity of the mucins decreases with age. Four glycosyltransferases involved in mucin biosynthesis [Gal beta 3GalNAc:(GlcNAc-GalNAc)beta 6 N-acetylglucosaminyl-, GalNAc:beta 3 galactosyl-, Gal:alpha 2 fucosyl-, and GalNAc alpha 2----6 neuraminyltransferase] are present in tracheal epithelium of ferrets at all ages. Activities of all but the neuraminyltransferase decrease with age. The relatively greater neuraminyltransferase activity is consistent with increased incorporation of sialic acid into secreted mucins over the same age span. Conversely, diminution of fucosyltransferase relative to galactosyltransferase activity may contribute to the lower fucose content and lower blood group A activity of mucins secreted by mature ferret tracheas.(ABSTRACT TRUNCATED AT 250 WORDS)

Epithelial cell dysfunction in cystic fibrosis: implications for airways disease

An important pathophysiologic factor in CF airways is the failure to clear poorly hydrated secretions. The water deficit in CF mucous secretions can now be ascribed to a fundamental defect of epithelial cell regulatory processes which promotes sodium reabsorption from surface liquids and interferes with chloride secretion onto the luminal surface. In addition, it is now known that CF airway epithelial cells oversulfate high molecular weight glycoconjugates, both secreted and cell surface-associated. Oversulfation of glycoconjugates may contribute to the altered clearance properties of CF airways mucus and in addition could favor colonization of airways by organisms such as P. aeruginosa.

Increased sulfation of glycoconjugates by cultured nasal epithelial cells from patients with cystic fibrosis

Cystic fibrosis (CF) respiratory epithelia exhibit abnormal anion transport that may be linked to abnormal lung defense. In these studies, we investigated whether primary cultures of CF respiratory epithelial cells regulate abnormally the sulfate content of high molecular weight glycoconjugates (HMG) participating in airways' mucosal defense. HMG, including glycosaminoglycans and mucin-type glycoproteins released spontaneously into medium and HMG released from cell surfaces by trypsin, were metabolically labeled with 35SO4- and [6-3H]-glucosamine (GlcN) or 35SO4- and [3H]serine. All three classes of HMG from CF cells exhibited 35S/3H labeling ratios 1.5-4-fold greater than HMG from normal or disease control cells. Differences for labeling ratios of HMG from CF cells were shown to be the consequence of increased 35SO4- incorporation rather than decreased peptide synthesis and release or HMG glycosylation. The buoyant density of CF mucin-type HMG also was increased, consistent with increased sulfation. These observations suggest that oversulfation of a spectrum of HMG is a genetically determined characteristic of CF epithelial cells and may play an important pathophysiological role by altering the properties of mucous secretions and/or the interactions between selected bacteria and HMG at the airways' surface.

Development, organization, and function of tight junctional complexes in the tracheal epithelium of infant ferrets

The surface epithelium of newborn ferret airways matures rapidly in the first month of life. Prominent developmental features include a transition from predominantly non-ciliated to ciliated cells, quantitative and qualitative changes in secretion of macromolecules, and a transition from secretory to absorptive patterns of ion transport. Freeze-fracture replicas of ferret tracheal epithelium from 0 to 28 days of age exhibited progressive developmental patterns in tight junctional structure from beaded, unclosed patterns in newborns to more closed patterns at 28 days. Strand number increased while the depth of tight junctional structures and the proportion of strands exhibiting discontinuity decreased postnatally. Total transepithelial conductance, paracellular conductance, and cell size decreased over the first month. Our data suggest that changes in physiological parameters that reflect epithelial tight junction permeability can be attributed, at least in part, to maturation of this intercellular junction during the postnatal period.

Features of developing ferret tracheal epithelium: ultrastructural observations of in vivo and in vitro differentiation of ciliated cells

Ultrastructural features of the developing, surface epithelium of ferrets from birth to 28 days of age were characterized. Progressive ciliogenesis in vivo was observed, beginning with cells covering the membranous portion of the trachea. Emerging cilia appeared in ultrathin sections and by scanning electron microscopy at sites correlating with accumulation of integral membrane particles seen in freeze-fracture preparations. Two patterns of ciliogenesis were observed: (1) the random emergence of cilia over the apical cell surface, and (2) initial emergence of cilia at the peripheral boundary of the luminal border of individual cells. Novel, ringlike structures were observed on the surfaces of nonciliated cells at all ages studied. Active ciliogenesis as well as the appearance of ring structures also were documented in the superficial epithelium from 1- to 5-day-old animals maintained in vitro for up to 4 days.

Developmental changes in glycoconjugate secretion by ferret tracheas

Surface epithelium and submucosal glands of the ferret trachea undergo extensive postnatal development. This study examined developmental changes in rates of release and types of high molecular weight glycoconjugates secreted by explanted ferret tracheas. Digestion with bovine testicular hyaluronidase separated the high molecular weight glycoconjugates into two types, hyaluronidase-resistant mucins and hyaluronidase-susceptible glycosaminoglycans. Release rates were measured under unstimulated conditions and in the presence of known secretagogues. The unstimulated rate of release of total 3H-glycoconjugates was 4-fold higher at birth than after complete maturation. The mucin content varied from 39 to 74% of total 3H-glycoconjugates; however, no age-related pattern was observed for mucin/glycosaminoglycan ratios. The rate of release of 3H-mucins was 6-fold higher at birth than in the adult but rapidly dropped to adult levels by 28 days of age. The secretory cells in the tracheal epithelium of newborn ferrets had more abundant rough endoplasmic reticulum than did mature goblet cells, suggesting increased synthesis of secretory product. Response to methacholine and trypsin, both known stimulators of mucin release, was not observed until 28 and 54 days of age, respectively. Incorporation of 35S-sulfate into mucins relative to that for 3H-glucosamine increased with age, consistent with increasingly acidic histochemical staining properties of secretory cells. These developmental differences in rates of release, modulation of release, and relative sulfation of mucins may represent changes in secretory and synthetic mechanisms of the secretory cells.

Postnatal development of tracheal surface epithelium and submucosal glands in the ferret

We explored the usefulness of the postnatal ferret as a model for early developmental events in the large airways, using light and scanning electron microscopy. In the first 28 postnatal days, ferret tracheal surface epithelium and glands undergo dramatic growth and development. Tracheal surface area increases 8-fold. At birth, ciliated cells are sparse (9.4 +/- 1.2% of total epithelial cells). A significant increase in ciliated cells is observed at weekly intervals and by day 28 the ciliated cell is the predominant cell type (54.2 +/- 2.8% of total epithelial cells). Secretory cells decrease from 66.4 +/- 1.0% at birth to 22.2 +/- 2.8% of total epithelial cells. Histochemical staining of the granules of the epithelial secretory cells changes from predominantly non-acidic (staining with PAS but not Alcian blue) to predominantly acidic (staining also with Alcian blue). During the same time interval, tracheal glands develop from intraepithelial cellular aggregates devoid of secretory granules at birth into complex, submucosal tubuloacinar structures composed predominantly of cells containing non-acidic secretory granules at 28 days. Therefore, infant ferrets offer an opportunity to examine the structural and functional components of the mucociliary clearance mechanism at developmental stages which occur prenatally in many laboratory animals and in humans.

Immune complexes and complement abnormalities in patients with cystic fibrosis. Increased mortality associated with circulating immune complexes and decreased function of the alternative complement pathway

Serum samples from 139 patients with cystic fibrosis (CF) were tested for complement abnormalities and circulating immune complexes (CIC). We found no consistent changes in whole complement activity. However, we found CIC in 29% of these patients and decreased activity of the alternative complement pathway (ACP) in 36%. During 5 yr of observation, mortality was much higher in patients whose sera contained CIC (p less than 0.001) or decreased ACP activity (p less than 0.01). Of patients with both abnormalities, 31% died; however, no deaths occurred in patients with normal ACP activity and negative tests for CIC (p less than 0.001). During a subsequent 2.5-yr period, 55% of patients greater than or equal to 21 yr old with both findings died. In contrast, no deaths occurred in older patients lacking this combination (p = 0.0062). Circulating immune complexes but not decreased ACP activity were an independent risk factor for death. Our findings support the hypothesis that humoral immune mechanisms may contribute to morbidity and mortality in CF.

Altered urinary excretion of elastin cross-links in premature infants who develop bronchopulmonary dysplasia

In order to determine whether elastin degradation is increased in infants whose respiratory insufficiency requires ventilation with high concentrations of O2, we quantitated, by amino acid analysis, the elastin degradation products (desmosines) excreted in the urine of 14 premature male infants during the first 3 wk of life. Eight of these infants, the "low-O2" infants, did not have severe lung disease and did not require more than 40% O2 beyond the first 8 h of life. The other 6 infants, selected retrospectively because they developed bronchopulmonary dysplasia (BPD), were ventilated with more than 60% O2 for at least the first 72 h of life. The pattern of desmosine excretion observed in infants who developed BPD differed significantly (p less than 0.05) from the excretion pattern seen in "low-O2" infants during the first 3 wk of life. At the end of the first week of life, desmosine excretion was significantly greater (p less than 0.05) in the infants who later developed BPD than in the "low-O2" infants without severe lung disease. From Days 7-9 to 20-22, desmosine excretion increased in the "low-O2" infants from 6.9 +/- 1.7 micrograms/kg to 9.0 +/- 3.5 micrograms/kg. In contrast, desmosine excretion did not remain elevated in the BPD infants, decreasing from 10.6 +/- 2.2 micrograms/kg to 6.1 +/- 2.9 micrograms/kg during the same period. In the BPD infants, elevated desmosine excretion through Day 9 is likely to reflect lung injury, whereas decreased desmosine excretion beyond Day 9 suggests that elastin synthesis and turnover is impaired, possibly as a result of nutritional deficiencies.(ABSTRACT TRUNCATED AT 250 WORDS)

Proteinases of Pseudomonas aeruginosa evoke mucin release by tracheal epithelium

We have determined the potential of exoproducts from pathogenic bacteria to stimulate the release of high molecular weight mucins from goblet cells of airway epithelium in a rabbit tracheal explant system. Culture supernatants from proteolytic strains of Pseudomonas aeruginosa and Serratia marcescens, but not supernatants from a number of non-proteolytic strains, released mucins from goblet cells. Highly purified elastase and alkaline proteinase from P. aeruginosa stimulated goblet cell mucin release in a dose-dependent fashion. Lipopolysaccharide, exotoxin A, and alginate of P. aeruginosa did not possess mucin release properties. Proteolytic activity was required for mucin release by P. aeruginosa elastase, but such release in goblet cells was not mediated by cyclic AMP. Morphologic studies suggested rapid release of mucins from goblet cells was response to elastase by a process resembling apocrine secretion. Several nonbacterial proteinases mimicked the effect of Pseudomonas proteases. These studies provide support for the hypothesis that bacterial and other play a role in the pathogenesis of mucus hypersecretion in acute and chronic lung infections.

The alpha 2-adrenergic system of the platelet in cystic fibrosis

The ability of norepinephrine to inhibit prostaglandin E1 (PGE1)-stimulated accumulation of adenosine 3':5' cyclic monophosphate (cyclic AMP) in intact washed platelets was determined in 12 patients with cystic fibrosis, 6 parents of patients with cystic fibrosis, and a total of 21 healthy age-matched controls. Patients with cystic fibrosis and their parents did not differ from their age-matched controls in basal or PGE1-stimulated levels of cyclic AMP, nor in the dose dependent inhibition of cAMP accumulation by norepinephrine. Moreover, binding sites for [3H]-dihydroergocryptine were present in normal numbers and had normal ligand affinity in platelet membranes from patients with cystic fibrosis. In all measures tested, the alpha 2-adrenergic system in the platelet was normal in cystic fibrosis.

Time course of hemosiderin production and clearance by human pulmonary macrophages

Tracheal aspirates from four previously healthy infants with acute pulmonary hemorrhage, and small volume bronchial lavages from children undergoing flexible fiberoptic bronchoscopy were examined for pulmonary alveolar macrophages (PAM) containing hemosiderin. Hemosiderin formation was also studied in vitro. Macrophages containing hemosiderin were first seen in tracheal aspirates 50 hours after an acute pulmonary hemorrhage and after 72 hours in cultured macrophages. A small percentage of the PAM recovered by bronchoalveolar lavage from both adults and children contained hemosiderin. Hemosiderin was rapidly cleared from the lungs following an acute pulmonary hemorrhage.

Effects of alpha-tocopherol on platelet membrane function in cystic fibrosis

Patients with cystic fibrosis and their parents were reported to have abnormal platelet aggregation responses to prostaglandin E1. To determine whether this is a property of the platelets, we studied the adenosine 3':5'-cyclic monophosphate (cAMP) response of washed platelets to prostaglandin E1. The cAMP response to prostaglandin E1 was the same in platelets from obligate heterozygotes for cystic fibrosis and from those of healthy controls. Patients with cystic fibrosis who had deficient vitamin E levels (plasma alpha-tocopherol, less than 500 micrograms/dl) had significantly (p less than 0.01) reduced platelet cAMP response to prostaglandin E1 compared with patients who had sufficient vitamin E, and supplementation with water-miscible vitamin E in these patients resulted in significant increases in plasma alpha-tocopherol levels (p less than 0.01) and in cAMP response to prostaglandin E1 (p less than 0.05). Plasma alpha-tocopherol levels correlated significantly with platelet cAMP response to prostaglandin E1 in patients with cystic fibrosis (r = 0.58, p less than 0.05). However, plasma alpha-tocopherol level was unrelated to the lymphocyte and granulocyte cAMP response to prostaglandin E1 or to the platelet cAMP response to alpha 2-adrenergic stimulation. Our data suggest that patients with cystic fibrosis have no inherited defect in platelet cAMP response to prostaglandin E1. In patients who have sufficient vitamin E, cAMP responses to prostaglandin E1 are normal in all the formed elements of the blood.

Concentrations of alpha 1-proteinase inhibitor and alpha 2-macroglobulin in serum and lung secretions of intubated infants

In order to determine the relative importance of the two proteinase inhibitors, alpha 1-proteinase inhibitor (alpha 1 PI) and alpha 2-macroglobulin (alpha 2M), in defending the infant lung against proteolytic attack, we measured concentrations of alpha 1PI and alpha 2M in both serum and lung secretions of infants intubated for respiratory insufficiency. In addition, we compared the concentration of each of the proteinase inhibitors in lung secretions with the serum concentrations of the proteinase inhibitor on the same day. Serum and secretions of all infants contained quantifiable levels of alpha 1PI. All serum samples had measurable amounts of alpha 2M. Ninety-two percent of the infants and 78% of all secretion samples tested contained alpha 2M. Molar ratios of alpha 1PI/albumin did not change as a function of gestational age in either serum or secretions. Serum alpha 2M/albumin also remained unchanged, but in lung secretions alpha 2M/albumin increased significantly with gestational age. With increasing postnatal age up to 44 days, mean levels of serum alpha 1PI, alpha 1PI/albumin, alpha 2M and alpha 2M/albumin increased. There was a greater increase in serum alpha 2M than in alpha 1PI as evidence by a decreasing molar ratio of alpha 1PI/alpha 2M with increasing postnatal age. In lung secretions, only alpha 1PI/albumin increased with postnatal age. Mean values for the molar ratio of alpha 1PI/alpha 2M in lung secretions ranged from 17 at 1-5 d to 22 at 11-44 d compared with the ratio of 200 reported for healthy adults (7).

The carbohydrate content of IgG from patients with cystic fibrosis

We compare the complete carbohydrate composition of IgG purified from the serum of patients with cystic fibrosis (CF) with that of control subjects. Our results indicate that IgG from cystic fibrosis patients is underglycosylated with respect to galactose and sialic acid, the two terminal sugars on the antennae of the complex-type oligosaccharide chains found on IgG. The galactose content, as determined by gas liquid chromatography, was 2.81 +/- 0.86 (S.D.) mole/mole of IgG for normal subjects versus 1.5 +/- 0.39 for CF subjects (P less than 0.025). Sialic acid content, as determined by the Warren procedure, was 1.33 +/- 0.39 for normals versus 0.47 +/- 0.10 for CF subjects (P less than 0.001). Neither galactose nor sialic acid values for the two groups overlapped. The contents of the core sugars, mannose and glucosamine, and of fucose were not significantly different. When the data are expressed as residues per 3 moles mannose, similar results are obtained. We suggest that immune complex formation, which has been documented in many CF patients, exposes sugar chains of IgG molecules to hydrolytic activity of serum glucosidases, resulting in partial removal of the more peripheral sugars. Because serum glycoproteins missing sialic acid and galactose are not readily cleared from the circulation, the observed changes may contribute to elevated levels of IgG and immune complexes in older people with CF.

Surface architecture of the mucosal epithelium of the cat trachea: I. Cartilaginous portion

The mucosal covering of the cartilaginous portion of the cat trachea was studied by correlated light, transmission-electron, and scanning-electron microscopy. While in some areas the ciliated pseudostratified epithelial lining is fairly smooth in contour, in other areas it contains longitudinally oriented, cilia-lined clefts. Ducts from submucosal glands sometimes open into the base of these clefts, or into funnel-shaped stomata that are lined by either ciliated or microvillus-rich cells. Specialized epithelial cells are occasionally associated with the clefts or with other regions of surface epithelium. In single sections, these cells appear to contain a cilium-lined vacuole, but serial sectioning has demonstrated that these apparent vacuoles actually are long intracellular invaginations in enormously elongated cells that extend longitudinally in the plane of the epithelium. The function of these cells is undetermined. Basal cells are attached to the lamina densa by means of hemidesmosomes that consistently lack peripheral densities; in contrast, the tall columnar cells have no hemidesmosomes.

Surface architecture of the mucosal epithelium of the cat trachea: II. Structure and dynamics of the membranous portion

Bronchoscopic examination of anesthetized cats revealed that the trachea is capable of considerable change in caliber via lateral expansion of the membranous trachea. The morphological basis for this expansile capacity was determined by correlated light microscopy and scanning and transmission electron microscopy. The organization of the membranous trachea differs from that of the cartilaginous trachea. The mucosa is arranged in a series of longitudinal folds that open like an accordion when stretched laterally. These fold are not random, but appear to depend on rows of nonciliated, microvillus-rich cells that form flexure lines in the surface epithelium. The mitochondria in such cell have a condensed configuration, indicating a high level of oxidative metabolism and suggesting that they may participate in transport processes that modify the luminal contents. Goblet cells, which are relatively sparse in the membranous trachea, have mitochondria in which the prominence of matrix granules and degree of mucus storage are inversely related. Mitochondrial morphology allows goblet cells that have discharged their mucin content to be readily distinguished from the microvillus-rich cells, even when their luminal surfaces lie outside the thickness of a section.

Beta adrenergic receptors in lymphocytes and granulocytes from patients with cystic fibrosis

Intact lymphocytes from patients with cystic fibrosis (CF) produce significantly (P less than 0.001) less adenosine 3':5' cyclic monophosphate (cAMP) than normal lymphocytes in response to isoproterenol (10(-8)-10(-4) M), although the basal cAMP content and the response to prostaglandin E1 are normal. Obligate heterozygotes for CF have significantly (P less than 0.005) reduced cAMP response to isoproterenol as well, suggesting a genetic component in the beta adrenergic deficiency in CF. The number of beta adrenergic receptors, as determined by equilibrium binding of [3H]dihydroalprenolol to lymphocyte particulates, is the same in normal lymphocytes (969 +/- 165 receptors/cell) and lymphocytes from patients with CF (1,333 +/- 263 receptors/cell). Binding properties of the receptor for both antagonist and agonist, as assessed by KD for dihydroalprenolol and Ki for (-)-isoproterenol, are also normal in the CF lymphocytes. Similarly, in granulocytes from patients with CF, the cAMP response to isoproterenol (10(-8)-10(-4) M) is significantly reduced compared with healthy controls (P less than 0.03), as is the response of granulocytes from obligate heterozygotes (P less than 0.05). Again, the basal cAMP levels and the response to prostaglandin E1 are normal. The number of beta adrenergic receptors, as determined by equilibrium binding of [3H]dihydroalprenolol to granulocyte particulates, was the same in normal (1,462 +/- 249 receptors/cell) and CF (1,621 +/- 221 receptors/cell) preparations. Binding properties of the receptor for both agonist and antagonist, as assessed by KD for dihydroalprenolol and Ki for isoproterenol, are normal in CF granulocyte particulates. The lymphocyte and granulocyte beta adrenergic defect in CF cannot be explained by abnormalities of the beta adrenergic receptor or of adenylate cyclase itself. Receptor-cyclase coupling is the most likely site of the heritable beta adrenergic defect in CF.

Beta-adrenergic modulation of mucin secretion in cat trachea

The mechanism of beta-adrenergic regulation of mucin secretion was investigated in cat trachea in vitro. beta-Adrenergic agonists increased the release of [35S]SO4-radiolabeled mucin and mucosa-submucosal adenosine 3',5'-cyclic monophosphate (cAMP) levels in a dose- and time-dependent manner. The relative potencies and efficacies of l-isoproterenol, l-epinephrine, l-norepinephrine, terbutaline, and dobutamine for physiological and biochemical events were similar. The effect of these agonists were blocked by d-l-propranolol. 3-Isobutyl-l-methylxanthine (IBMX) and 8-bromo-cAMP mimicked the effects of the agonists on mucin release. IBMX increased cAMP levels and potentiated the increase in cAMP levels effected by beta-adrenergic agonists. The half-maximal effects of l-isoproterenol on cAMP levels and mucin release were attained at 1.6 and 8.8 min, respectively. Three major mucosa-submucosal proteins of apparent molecular weights of 49,000, 54,000, and 59,000 daltons displayed reduced binding of the photoaffinity label 8-N3-[32P]cAMP when endogenous cAMP levels were increased with l-isoproterenol and/or IBMX. The first two proteins correspond in electrophoretic mobility to the regulatory subunits of type I and type II cAMP-dependent protein kinases, respectively. The 59,000-dalton cAMP binding protein may be the phosphorylated form of the regulatory subunit of type II cAMP-dependent protein kinase. These data are consistent with the hypothesis that beta-adrenergic modulation of tracheal mucin release is mediated by cAMP and suggest that activation of cAMP-dependent protein kinases may be involved in the neurohormonal effects.

Treatment and prognosis of nasal polyps in cystic fibrosis

Nasal polyposis complicated the course of fibrosis in 157 (26%) of 605 patients. Onset before age 5 years or after age 20 years was rare. Polyposis was the initial symptom of cystic fibrosis in 13 patients. Common symptoms included obstruction to nasal air flow, mouth breathing, epistaxis, and rhinorrhea. Intranasal and oral corticosteroids and antihistamines were ineffective in preventing recurrences but did occasionally afford symptomatic relief of obstruction. Nineteen (31%) of 62 patients who never had surgery had spontaneous and permanent disappearance of polyps. Simple polypectomy was an adequate procedure for patients with substantial nasal symptoms. There were no visual complications. Other surgical complications were rare. Children and adolescents with nasal polyps should have sweat tests by pilocarpine iontophoresis to rule out cystic fibrosis.

Neurohormonal receptors and cyclic AMP-binding proteins in rabbit tracheal mucosa-submucosa

Neurohormones and drugs that alter in vitro tracheal electrolyte transport and mucus glycoprotein secretion were examined for their ability to alter cyclic nucleotide accumulation in a smooth muscle-free preparation of rabbit tracheal mucosa-submucosa. cAMP levels were increased by beta-adrenergic agonists, histamine, 2-Cl-adenosine and prostaglandin E1. cGMP levels were increased by carbachol. The phosphodiesterase inhibitor isobutylmethylxanthine increased cAMP and cGMP levels and potentiated only the beta-adrenergic effects. The beta-adrenergic effects were blocked by (+/-)-propranolol and the effects of histamine by diphenhydramine, atropine and (+/-)-propranolol. Atropine blocked the carbachol effects. The isolated surface epithelium from rabbit trachea had higher basal cAMP levels and greater response to beta-adrenergic agonists and isobutylmethylxanthine than the mucosa-submucosa. Two major cAMP-binding proteins in the tracheal mucosa-submucosa were identified with the photoaffinity label 8-N3-[32P]cAMP. Agents that increased cAMP levels also decreased photoaffinity labelling, suggesting that these two cAMP-binding proteins were being occupied in the intact cell. The molecular weights of the proteins were 50 000 and 54 000 and correspond in electrophoretic mobility to the regulatory subunits of Type-I and Type-II cAMP-dependent protein kinases, respectively. The results are consistent with the hypothesis that epithelial functions in the airways are modulated by a number of agonists which increase cyclic nucleotide levels. The effects of beta-adrenergic agonists is apparently mediated by activation of adenylate cyclase and subsequent activation of cAMP-dependent protein kinases.

Mucin release from rabbit tracheal epithelium in response to sera from normal and cystic fibrosis subjects

We have developed an assay for the release of mucous glycoproteins secreted by rabbit tracheal mucosa to study the mucus-stimulating properties of cystic fibrosis (CF) serum. Glycoproteins are labeled to equilibrium with both [35]-sulfate and [3H]-glucosamine. The relative secretory rate (RSR) of these glycoproteins is assessed after incubation with 50% (v/v) CF and control sera. Serum from all sources significantly increased the RSR for incubation times ranging from 10 min to 4 h. CF serum produced a significantly greater RSR than control serum after 10 min exposure, but not after longer exposure intervals. After 10 min, RSR for [35SO4]-glycoproteins was 3.6 +/- 0.2 in the presence of sera from healthy individuals, and 2.3 +/- 0.4 in the presence of sera from control patients with lung disease. Heterozygote RSR values were usually higher than control values, but not different than CF homozygote values. The CF serum activity was reduced by freezing and thawing. Increasing the calcium content of incubation medium did not alter serum effects. Calcium inophore A23187 did not mimic CF serum activity. High molecular weight and albumin, but not IgG, fractions from Sephadex G-200 chromatography of CF and control sera generally contained high levels of mucin-release activity. No chromatographic pattern of activity was distinctive for CF.

Obstructive azoospermia as a diagnostic criterion for the cystic fibrosis syndrome

In some male patients with findings characteristic of cystic fibrosis, but normal sweat chloride concentrations, the demonstration of obstruction azoospermia has been pivotal in diagnosis. It is proposed that cystic fibrosis be diagnosed if the patient has at least two of three major criteria (marked rise in sweat chloride concentration, chronic obstructive pulmonary disease and pseudomonas infection, and unexplained obstructive azoospermia) or has one major criterion together with one of several minor criteria--including positive family history and childhood onset of exocrine pancreatic insufficiency. Inclusion of unusual variants within the cystic fibrosis syndrome has major theoretical implications for pathogenesis and practical importance for genetic counselling and patient care.

A comparative study of lysozyme and its secretion by tracheal epithelium

Tracheal explants from baboon, ferret, dog, mouse, hamster, rat guinea pig, chicken, sheep, rabbit and cat were maintained in vivo for 24 to 72 hr. Bathing media were analyzed for lysozyme content. Secretory rates were compared to the rate obtained for human trachea in our earlier work. These rates ranged from 807 micrograms lysozyme/g tissue/24 hr for human trachea to 11 micrograms lysozyme/g tissue/24 hr for chicken trachea. Secretory rates for baboon, ferret dog, mouse, hamster, rat, and guinea pig tracheal lysozyme fell within this range in decreasing order. No detectable lysozyme was released from sheep, cat, or rabbit explants. Lysozyme secretion did not correlate with the presence or absence of submucosal glands. Lysozyme from laboratory animals in all cases differed with respect to electrophoretic mobility and immunochemical properties from human lysozyme. These observations provide physiological, physiochemical, and immunochemical information which will facilitate the use of lysozyme to assess secretion of macromolecules in in vitro and in vivo studies of airway epithelium.

Treatment and prognosis of rectal prolapse in cystic fibrosis

Rectal prolapse occurred in 112 (18.5%) of 605 cystic fibrosis patients. In 48 patients prolapse preceded diagnosis of cystic fibrosis, but physicians (pediatricians, pediatric and general surgeons, and proctologists) rarely appreciated its importance as a symptom of this disease. Prolapses frequently cease with institution of pancreatic enzyme replacement therapy following diagnosis of cystic fibrosis. However, even when the disease remains undiagnosed, the symptom is often transient and frequently resolves at 3-5 yr of age. Prolapse occurring initially after cystic fibrosis is diagnosed rarely responds to manipulation of diet or enzyme doses. Many patients develop a method of reduction which involves voluntary abdominal, perineal, and gluteal muscles and does not require manual pressure on the prolapsed segment. Most patients do not need specific treatment for the prolapse. Surgery is rarely necessary. A sweat test should be obtained on any child who has had even a single episode of rectal prolapse.

Identification of a major heparin-precipitable protein in human serum and its relationship to cystic fibrosis

Heparin binding to serum proteins and their subsequent precipitation is reportedly increased in cystic fibrosis (CF). We have confirmed this finding for CF patients over the age of 12 [11.34 +/- 2.42 mg/ml precipitated protein for normals (n = 19) versus 17.46 +/- 4.60 mg/ml for CF patients (n = 37), P less than 0.001; 0.629 +/- 0.098 mg/ml precipitated heparin for normals versus 0.789 +/- 0.206 for CF patients, P less than 0.01]. We have also shown that patients with a variety of pulmonary diseases unrelated to CF do not show this effect. When the amounts of protein and heparin precipitated are compared with the amount of IgG found in the whole serum sample, the correlation coefficients (protein r = 0.77; heparin, 0.74; n = 81) are significant at a level of P less than 0.001. In addition, the report that young CF patients exhibit hypogammaglobulinemia prompted us to examine serum samples from CF patients and age-matched controls under the age of 12. No differences were found. To investigate the molecular basis for this effect, sera from patients with CF and from age-matched controls were precipitated with 50 mg% heparin at pH 5.57. Pellets resolubilized in 8 M urea were fractionated on DEAE-Sephadex and analyzed by double-immunodiffusion, SDS-PAGE, immunoelectrophoresis, and radial immunodiffusion. IgG constituted 55-56% of the eluted protein. When serum from all donors was fractionated by Staph A-Sepharose into IgG and non-IgG fractions, 85-89% of heparin precipitable protein was in the IgG fraction.

EDTA-mediated separation of cat tracheal lining epithelium

After specimens of cat trachea were incubated for 2 hr in 20 mM EDTA, the epithelium could easily be stripped from the mucosal surface with a dissecting needle. The epithelium was cleanly separated from its basal lamina, which remained fixed to the lamina propria. Epithelial cells were well preserved, junctional complexes were structurally intact, and there was no widening of intercellular spaces. The inferior epithelial surface was irregular, with numerous membrane-bound blebs arising from the constituent epithelial cells. Hemidesmosomes, which are found only on basal cells, were covered by a nap of fine filaments, the remnants of the filaments that normally traverse the lamina lucida. In many basal cells, cleaved hemidesmosomes were internalized, probably representing a stage in their lysosomal degradation. The basal lamina adhering to the lamina propria appeared in the transmission electron microscope as a sinuous linear density. In the scanning electron microscope, the basal lamina surface had an irregularly corrugated appearance. The basal lamina continued into the stomata of the submucosal gland ducts, which intersected the surface at an acute angle. Anchoring fibrils identical to those associated with stratified squamous epithelium were found in significant numbers on the connective tissue face of the basal lamina. Separation of tracheal tissues may provide a means whereby secretory activity and products of epithelium and submucosal glands can be individually assessed.

Mucous glycoproteins from cat tracheal goblet cells and mucous glands separated with EDTA

Respiratory tract mucous glycoproteins (MGP) are secreted by goblet cells in the surface epithelium and by submucosal glands. The MGP in airway secretions collected in vivo and from airway explants in vitro represent an admixture of secretions from these sources. Incubation of cat tracheal explants in 20 mM EDTA allowed physical separation of the surface epithelium from the underlying tissues and the culture of each isolated secretory element. Separated tissues appeared morphologically intact and continued to secrete MGP. The MGP arising from the surface epithelium had more sialic acid relative to galactose and N-acetylglucosamine and appeared to be less highly sulfated, as determined by DEAE cellulose chromatography, than MGP from submucosal glands. The EDTA-mediated separation of the airway secretory elements may allow further investigation into specific secretory functions of these two epithelial elements.

Are measurements of urine enzymes useful during aminoglycoside therapy?

We prospectively evaluated concentrations of beta-D-galactosidase, alpha-L-fucosidase, beta-D-N-acetylglucosaminidase, and lysozyme in urine from normal subjects, ambulatory patients with cystic fibrosis (CF), and CF patients with previously normal renal function who were receiving intravenous aminoglycoside (AG) therapy. Enzyme activities were generally low or negligible in subjects not receiving AG. Enzymuria was documented during 12 of 13 AG treatment courses and most frequently involved beta-D-N-acetylglucosaminidase excretion. In nine courses, enzymuria occurred in the absence of proteinuria or elevations of blood urea nitrogen and serum creatinine. In three courses attended by enzymuria and evidence of nephrotoxicity, neither the time of appearance nor the magnitude of enzymuria was different from that of nonnephrotoxic patients. In two of these three treatment courses, enzymuria preceded clinical evidence of nephrotoxicity of 16 and 5 days, and in the third course enzymuria and elevation of blood urea nitrogen and serum creatinine occurred simultaneously. We conclude that enzymuria is not a reliable predictor of nephrotoxicity due to AG in CF patients and is not an indication of discontinue AG therapy.

Psychosocial functioning of children with cystic fibrosis

The adjustment of children with cystic fibrosis as rated by parents and teachers was compared to that of physically healthy siblings, normal children, and other chronically ill children. The findings indicated that children with cystic fibrosis achieved an age-adequate level of adjustment at home and school. Adjustment was largely unrelated to the severity of cystic fibrosis. As a group, chronically ill children had less adequate adjustment as rated by parents. However, severe adjustment problems were relatively rare. These findings are consistent with a growing body of literature which suggests that children with cystic fibrosis can cope reasonably well with life tasks and that emotional disturbance is not an inevitable consequence of the disease. Future studies of the cystic fibrosis population should study factors which differentiate adjusted from maladjusted children.