Anti-reflux surgery in lung transplant recipients: outcomes and effects on quality of life.

Fundoplication may improve survival after lung transplantation. Little is known about the effects of fundoplication on quality of life in these patients. The aim of this study was to assess the safety of fundoplication in lung transplant recipients and its effects on quality of life. Between June 1, 2008 and December 31, 2010, a prospective study of lung transplant recipients undergoing fundoplication was undertaken. Quality of life was assessed before and after surgery. Body mass index (BMI) and pulmonary function were followed up. 16 patients, mean ± sd age 38 ± 11.9 yrs, underwent laparoscopic Nissen fundoplication. There was no peri-operative mortality or major complications. Mean ± SD hospital stay was 2.6 ± 0.9 days. 15 out of 16 patients were satisfied with the results of surgery post fundoplication. There was a significant improvement in reflux symptom index and DeMeester questionnaires and gastrointestinal quality of life index scores at 6 months. Mean BMI decreased significantly after fundoplication (p = 0.01). Patients operated on for deteriorating lung function had a statistically significant decrease in the rate of lung function decline after fundoplication (p = 0.008). Laparoscopic fundoplication is safe in selected lung transplant recipients. Patient benefit is suggested by improved symptoms and satisfaction. This procedure is acceptable, improves quality of life and may reduce deterioration of lung function.

From gastric aspiration to airway inflammation.

The airways are poorly protected from potentially damaging agents contained within gastric contents. While digestive factors are obvious damaging agents, gastric aspiration may also deliver microbial agents, cytokines or food antigens to airway tissues. Direct damage or the triggering of the inflammatory cascade by gastric aspiration is believed to drive airways disease onset and/or progression. Evidence exists from experimental models demonstrating direct instillation of damaging factors to a range of airways epithelia causes damage and/or an inflammatory response. Clinical longitudinal studies have also noted an association between the presence of biomarkers of reflux in airways samples and disease progression. A shared pathophysiology of many chronic airways diseases is a more negative intrathoracic pressure. Such changes would drive an increased abdominothoracic pressure gradient. These changes in respiratory mechanics mean that chronic lung disease patients may be predisposed to reflux and subsequent aspiration. Therefore, it appears that gastric aspiration and airways disease progression may be linked not solely as cause and effect, but seemingly within a vicious cycle. A range of physiological factors govern both occurrence of gastric reflux into the pharynx/larynx and could also increase the susceptibility of certain individuals to disease progression. A range of long-term surgical and pharmacological intervention studies are necessary to test the benefit of such therapies in reducing disease progression or driving symptom improvement. Such studies may be hampered by the reliability of available therapies in halting gastric aspiration and the difficulty in the clinical or biochemical assessment of gastric aspiration.

Targeting allograft injury and inflammation in the management of post-lung transplant bronchiolitis obliterans syndrome.

Chronic allograft dysfunction, manifesting as bronchiolitis obliterans syndrome (BOS), is the major cause of morbidity and mortality in human lung transplant recipients. While alloimmunity has a definite role, there is increasing interest in overall allograft injury and subsequent inflammation and remodeling. This review deals with nonalloimmune factors that may potentiate alloimmune injury. We discuss infection and reflux/aspiration as examples of allograft injury, which may lead to chronic loss of graft function and BOS. Surgical and nonsurgical treatments aimed at preventing these insults and improving survival are considered. The need for further evidence, including randomized-controlled trials, to evaluate the role of medical and surgical therapies is emphasized by the current literature.

The involvement of cell-to-cell signals in the development of a bacterial biofilm.

Bacteria in nature often exist as sessile communities called biofilms. These communities develop structures that are morphologically and physiologically differentiated from free-living bacteria. A cell-to-cell signal is involved in the development of Pseudomonas aeruginosa biofilms. A specific signaling mutant, a lasI mutant, forms flat, undifferentiated biofilms that unlike wild-type biofilms are sensitive to the biocide sodium dodecyl sulfate. Mutant biofilms appeared normal when grown in the presence of a synthetic signal molecule. The involvement of an intercellular signal molecule in the development of P. aeruginosa biofilms suggests possible targets to control biofilm growth on catheters, in cystic fibrosis, and in other environments where P. aeruginosa biofilms are a persistent problem.

Thickness and continuity of the adherent colonic mucus barrier in active and quiescent ulcerative colitis and Crohn's disease.

BACKGROUND: The colon is covered by a mucus barrier that protects the underlying mucosa and alterations in this mucus barrier have been implicated in the aetiology of inflammatory bowel disease (IBD). This study investigated the thickness and continuity of the mucus barrier in ulcerative colitis (UC) and Crohn's disease (CD) in comparison to normal controls. METHODS: Rectal biopsies were taken from 59 patients and cryostat sections stained with periodic acid-Schiff's/Alcian blue to visualise the mucus layer. Mucus thickness and continuity and goblet cell density were measured using light microscopy. RESULTS: An essentially continuous adherent mucus layer was observed in normal human rectum and there was no change in the mucus barrier in quiescent UC. In active UC there was a trend for the mucus layer to become progressively thinner and significantly more discontinuous as disease severity increased. In severe active UC the mucus layer thickness and goblet cell density were significantly reduced compared with normal controls while the percentage discontinuity significantly increased. CONCLUSION: It is not until severe UC that there is a global change in mucosal protection as a consequence of large regions lacking mucus, a decrease in secretory potential caused by a loss of goblet cells and a thinner, less effective mucus layer even when it is present.

A qualitative synthesis of gastro-oesophageal reflux in bronchiectasis: Current understanding and future risk.

Gastro-oesophageal reflux disease (GORD) is a common comorbidity in bronchiectasis, and is often associated with poorer outcomes. The cause and effect relationship between GORD and bronchiectasis has not yet been fully elucidated and a greater understanding of the pathophysiology of the interaction and potential therapies is required. This review explores the underlying pathophysiology of GORD, its clinical presentation, risk factors, commonly applied diagnostic tools, and a detailed synthesis of original articles evaluating the prevalence of GORD, its influence on disease severity and current management strategies within the context of bronchiectasis. The prevalence of GORD in bronchiectasis ranges from 26% to 75%. Patients with co-existing bronchiectasis and GORD were found to have an increased mortality and increased bronchiectasis severity, manifest by increased symptoms, exacerbations, hospitalisations, radiological extent and chronic infection, with reduced pulmonary function and quality of life. The pathogenic role of Helicobacter pylori infection in bronchiectasis, perhaps via aspiration of gastric contents, also warrants further investigation. Our index of suspicion for GORD should remain high across the spectrum of disease severity in bronchiectasis. Identifying GORD in bronchiectasis patients may have important therapeutic and prognostic implications, although clinical trial evidence that treatment targeted at GORD can improve outcomes in bronchiectasis is currently lacking.

Proteoglycan aggregates in adult human costal cartilage.

1. A sequential extraction procedure using isotonic KCl and 4.0 M guanidine hydrochloride was used to solubilise proteoglycans from adult human costal cartilage under conditions minimising autolysis. Up to 28% of the total tissue hexuronate was extracted. 2. Proteoglycan fractions were prepared from the extracts by CsCl equilibrium density gradient centrifugation. 3. Each fraction exhibited distinct electrophoretic heterogeneity. 4. Proteoglycans extracted by isotonic solutions are relatively small and may be in vivo degradation products of whole molecules. The major fraction (A1) from high ionic strength extracts has a composition similar to that of A1 proteoglycans from adult human articular cartilage. A2 fractions differ and are highly enriched in protein. 5. A1 and A2 fractions from high ionic strength extracts contain proteoglycan aggregates, but to a much lesser extent than found in other cartilages like bovine nasal or porcine epiglottal cartilage. 6. The aggregates can be dissociated and a 'subunit" proteoglycan isolated by CsCl density gradient centrifugation in 4.0 M guanidine hydrochloride. 'Subunits' can reaggregate partially, when mixed with fractions of lower density from the gradient. 7. Addition of hyaluronic acid to A1GuHCl promotes a large increase in the amount of aggregate present. 8. The hyaluronic acid content of costal cartilage is not deficient compared to that of other hyaline cartilages. 9. Polypeptides with molecular weights suggesting their identity as 'link proteins' are present in A1 and A2 fractions. 10. Additional polypeptides of higher molecular weight than link proteins are also present in A1 and A2 fractions. They may represent the hyaluronic acid binding region of proteoglycans and compete with 'whole' proteoglycans for hyaluronate in the tissue.

The effect of nanoparticle permeation on the bulk rheological properties of mucus from the small intestine.

The effectiveness of delivering oral therapeutic peptides, proteins and nucleotides is often hindered by the protective mucus barrier that covers mucosal surfaces of the gastrointestinal (GI) tract. Encapsulation of active pharmaceutical ingredients (API) in nanocarriers is a potential strategy to protect the cargo but they still have to pass the mucus barrier. Decorating nanoparticles with proteolytic enzymes has been shown to increase the permeation through mucus. Here we investigate the effect of poly(acrylic acid) (PAA) nanoparticles decorated with bromelain (BRO), a proteolytic enzyme from pineapple stem, on the bulk rheology of mucus as well as non-decorated poly(lactic-co-glycolic acid) (PLGA) nanoparticles. Porcine intestinal mucus from the small intestine was incubated for 30min in the presence of PLGA nanoparticles or polyacrylic nanoparticles decorated with bromelain (PAA-BRO). The effect of nanoparticles on the rheological properties, weight of gel, released glycoprotein content from mucus as well as the viscosity of liquid removed was assessed. Treatment with nanoparticles decreased mucus gel strength with PAA-BRO reducing it the most. PAA-BRO nanoparticles resulted in the release of increased glycoprotein from the gel network whereas mucus remained a gel and exhibited a similar breakdown stress to control mucus. Therefore it would be possible to use bromelain to increase the permeability of nanoparticles through mucus without destroying the gel and leaving the underlying mucosa unprotected.

The MUC2 gene product: a human intestinal mucin.

The MUC2 gene product is the first human secretory mucin protein core to be fully sequenced. Like the other eight human MUC genes identified to date, MUC2 is characterised by tandem and irregular repeat sequences rich in threonine and serine, the potential sites of attachment of the oligosaccharide chains. The MUC2 gene product is more than 5100 amino acids in its commonest allelic form and accounts for one fifth by weight of the mucin glycoprotein molecule (80% oligosaccharide side chains). The MUC2 product is polymerised end to end through disulphide bridges to form large secreted polymeric gel-forming mucins (Mr approximately 10(7)). The primary function of the MUC2 gene product is to provide a protective barrier between the epithelial surfaces and the gut lumen. There is decreased expression of MUC2 in colonic cancer and defective polymerisation of secreted mucin in ulcerative colitis. Elucidation of the MUC2 and other mucin gene sequences has opened the way for a full structural characterisation and an improved understanding of the structure and function of these complex mucus gel secretions.

Cutaneous malignant melanotic neurocristic tumors arising in neurocristic hamartomas. A melanocytic tumor morphologically and biologically distinct from common melanoma.

Cutaneous neurocristic hamartomas (CNH) are pigmented lesions of neural crest origin that involve the skin and superficial soft tissue. They consist of a complex proliferation of nevomelanocytes, schwann cells, and pigmented dendritic and spindled cells. Malignancies can arise within the lesions, but few studies have dealt with this issue. We studied seven cases of CNH in which malignancy supervened. They included four congenital and three acquired lesions that involved the head and neck (five cases) or back (two cases) in patients aged from 11 to 67 (mean, 32) years. Malignant tumors developed 15 to 67 (mean, 32) years after identification of the pigmented lesion in the congenital CNH and after 1 to 6 (mean 3.5) years in the acquired CNH. The malignant tumors had a deep intradermal or subcutaneous origin and lacked a junctional component. Most were circumscribed, multinodular, melanin-containing tumors composed of bland, small, rounded to spindled cells, focally displaying a trabecular or nested growth pattern. Nuclear palisading and perivascular pseudorosettes were present in several tumors. In two examples, the neoplasm consisted predominantly of large pleomorphic epithelioid cells. Tumors contained immunoreactive S-100 protein (all of seven cases), a melanoma-associated antigen (HMB-45)( five of six cases, neuron-specific enolase (five of seven cases) and vimentin (six of six cases). The four patients with congenital lesions tended to have multiple recurrences and died of disease after 2 to 20 (mean, 9) years, three with metastases, one with direct invasion of the posterior fossa. The three patients with acquired lesions are alive after 1 to 5 years two with persistent disease. In contrast to common melanomas, these tumors have a propensity to recur as bulky nodules and to metastasize after many years or decades. Because these tumors exhibit melanocytic differentiation and arise in hamartomatous lesions composed of neural crest derivatives, we have designated them cutaneous malignant melanotic neurocristic tumors.

The effects of heparin on lipoproteins in high-resolution electrophoresis of serum.

Sera from heparinized patients commonly display anodal slurring of both the alpha and beta lipoproteins when they are examined by high-resolution electrophoresis (HRE). In this study, the authors examined the effect of heparin and lipoprotein lipase on the electrophoretic migration of alpha and beta lipoproteins in sera. The addition of 10 to 1,000 units of heparin/mL to normal sera resulted in a concentration-dependent anodal slurring of the beta lipoproteins. At 40 units/mL, the beta lipoprotein band was not visible when the Paragon blue protein stain was used. The beta lipoprotein could be seen as a wide, faintly staining band with lipoprotein stain. The alpha lipoprotein band on the same gel was unaffected by the added heparin. High-resolution electrophoresis of other sera from patients who were therapeutically heparinized demonstrated anodal slurring of both alpha and beta lipoproteins independent of heparin concentration. Immunofixation electrophoresis (IFE) studies confirmed that apolipoproteins A and B were slurred within their respective bands. Heparin activates lipoprotein lipase with release of free fatty acids (FFA) from very low density lipoproteins and chylomicrons. To test this effect on migration, sera were incubated with lipoprotein lipase in vitro. The anodal slurring of both the alpha and beta lipoprotein was associated with the amount of FFA production. Individuals interpreting electrophoretic patterns should be aware that both the alpha and beta lipoproteins can migrate and slur anodally in heparinized patients. In addition, when the beta lipoprotein band interferes with the identification of monoclonal gammopathies, its migration can be selectively altered by the addition of 40 units/mL heparin to the sample.

Solitary fibrous tumor of the paranasal sinuses: CT and MR appearance.

We describe the CT and MR appearance of a solitary fibrous tumor of the paranasal sinuses with intracranial invasion. The tumor was hypointense on T2-weighted MR images and had a large calcific component that proved to be reactive remodelling of native bone.

Characterization of human middle ear mucus glycoprotein in chronic secretory otitis media (CSOM).

Middle ear effusion was obtained from children with chronic secretory otitis media undergoing myringotomy. The effusions contained about 120 mg/ml non-dialysable solids, of which 18-31% was mucus glycoprotein. The purified mucus glycoprotein had a composition characteristic of other mucus glycoproteins. Amino acid analysis of the glycoprotein indicates a protein core consisting of glycosylated regions resistant to proteolysis and non-glycosylated regions susceptible to proteolysis. Analysis of the mucus glycoprotein by gel filtration on Sepharose 2B showed that reduction caused a decrease in hydrodynamic size and proteolysis caused a further decrease. The difference was confirmed by sedimentation coefficient and viscosity measurements. The reduced glycoprotein had an intrinsic viscosity of 0.113 ml/mg and an S0(20) of 15.2S compared to a value of 0.018 ml/mg and 9.6S for the proteolytically digested glycoprotein. These results suggest a model for this middle ear mucus glycoprotein, in which the native glycoprotein is a large molecular mass polymer maintained by disulphide bridges. These disulphide linked glycoprotein units are broken down into smaller units by proteolysis. The mucus glycoprotein could not be purified completely free from low molecular mass components. A glycoprotein, susceptible to proteolysis Mr 28,000-33,000 co-fractionates with the major high molecular mass mucus glycoprotein.

Up-regulation of mucin secretion in HT29-MTX cells by the pro-inflammatory cytokines tumor necrosis factor-alpha and interleukin-6.

The pro-inflammatory cytokines IL-6 and TNF-alpha have been implicated in the pathogenesis of otitis media with effusion (OME). A disease where goblet cells proliferate in a modified respiratory epithelium, leading to the accumulation of a mucin-rich effusion in the middle ear cleft. The MUC5AC and MUC5B mucin gene products have been identified as components of these effusions. To determine the effect of IL-6 and TNF-alpha on MUC5AC and MUC5B secretion we have used HT29-MTX goblet cells, which secrete both types of mucins. MUC5AC and MUC5B mucin secretion was measured by an enzyme-linked immunosorbent assay (ELISA) using a specific monoclonal antibody NCL-HGM-45M1 and polyclonal antiserum TEPA, respectively. Time response (0-72 hours) and dose response (1.5-150 ng/ml) studies were carried out. IL-6 and TNF-alpha stimulated MUC5AC and MUC5B mucin secretion in a time dependent manner, both in pre-confluent and post-confluent cells. IL-6 (15 ng/ml and 20 ng/ml) produced a low and prolonged stimulation of mucin secretion that persisted for 72 hours, with peak response at 24 hours after induction. The IL-6-mediated mucin secretion at 24 hours was concentration-dependent, with a maximal effect at 15 ng/ml. TNF-alpha (20 ng/ml) induced rapid stimulation of mucin secretion within the first 24 hours, with peak response at 7 hours after induction. IL-6 and TNF-alpha exposure significantly increased MUC5AC secretion, but not MUC5B secretion. Maximal levels of cytokine-induced mucin secretion were detected in pre-confluent cells that showed one and a half- and two-fold increases in MUC5AC secretion after IL-6 and TNF-alpha stimulation, respectively, in comparison with post-confluent cells. The results presented here suggest that IL-6 and TNF-alpha generate a differential up-regulation of mucin secretion and thus contribute to the expression of mucin genes in inflammatory responses.

Mucolytic agents and otitis media with effusion.

Middle ear effusion was obtained from children with otitis media with effusion and separated into thick (mucoid) and thin (serous) pools. Both effusion types contained similar amounts of non-dialysable solids. However, the thick effusions contained more mucus glycoprotein than the thin effusions, 25% and 8.2% respectively. Amino acid and carbohydrate analysis of the CsCl purified mucus glycoproteins demonstrated that the glycoprotein from the thick and thin effusions differed in their protein core, those from the thick effusions possessing a higher percentage of serine and threonine, the amino acids to which the sugar side-chains attach. They are also more glycosylated. N-acetyl cysteine and mercaptoethanol caused a fall in the viscosity of solutions of purified middle ear glycoprotein and effusion homogenate. However, longer term incubation caused a rise above the starting viscosity. This effect was concentration-dependent, and was mediated by low molecular weight components in the effusion and not the mucus glycoprotein. S-carboxymethyl cysteine had no effect on the viscosity of either the purified mucus glycoprotein or the effusion homogenate. Therefore, to produce a decrease in effusion viscosity in vivo, the concentration of mucolytic reaching the middle ear and the time it remains there are critical factors.

Compositional differences between bilateral middle ear effusions in otitis media with effusion: evidence for a different etiology?

The aim of this study was to clarify the site of primary pathology in otitis media with effusion. Effusions were collected from 64 children with bilateral effusions at the time of myringotomy. The rheological properties and biochemical compositions of effusions were measured for 23 pairs of effusions, and the levels of the inflammatory mediators TNF alpha, IL-1beta, and IL-8 were measured in 41 pairs using specific enzyme-linked immunosorbent assays (ELISAs). Measurements from paired ears were compared using analysis of variance (ANOVA) tests and significant differences were found for reduced specific viscosity, mucin content, protein content, and levels of IL-8. The results demonstrate that the two ears have different immunological processes or rates of processes which might explain the significantly different rheological properties of effusions. This suggests that each ear undergoes pathological changes independently and has implications for using the opposite ear as a control in clinical trials.

Rheologic studies on middle ear effusions and their mucus glycoproteins.

The properties of pooled thick and thin middle ear effusions, from children with otitis media with effusion, were studied by viscometry. Mucus glycoproteins were responsible for effusion viscosity. Their percentage by weight in thick and thin effusions was 25% and 8.2%, respectively. N-acetylcysteine and 0.2 mol/L of mercaptoethanol caused a 39% viscosity drop in a 5-mg/mL glycoprotein solution, whereas S-carboxymethylcysteine had no effect. Treatment of thick effusions with 0.2 mol/L of mercaptoethanol initially caused a viscosity decrease followed by a gradual increase. Higher reducing agent concentrations (0.5 mol/L) caused a more rapid decrease followed by a rapid increase, presumably by causing nonspecific aggregation of reduced protein molecules. These results suggest that the concentration of and the time that a mucolytic is in the middle ear would be of prime importance in achieving the desired decrease in viscosity.

Mucus and H. pylori.

A continuous, adherent mucus gel layer with mucosal bicarbonate secretion is the initial protective barrier in the stomach and duodenum against erosion by the gastric juice. H. pylori resides within the adherent mucus gel layer close to the epithelial surface. The barrier function of the mucus layer in vivo depends on (i) its thickness, and (ii) its gel structure, a property which is linearly dependent on the polymeric mucin content. We have shown in vivo that H. pylori colonisation alone did not decrease the thickness of the adherent gastric mucus barrier, although there was a mean 20% decrease in mucus thickness in those H. pylori positive subjects with underlying gastric atrophy. There was, however, a significant mean 18% reduction in the gel-forming polymeric mucin content of mucus from H. pylori subjects, independent of underlying atrophy. Studies in vitro suggest this loss of gel structure might arise from a H. pylori mediated, high local pH generated by urease activity rather than by proteolysis. This study shows that H. pylori infection alone does not compromise the overall integrity of the mucus barrier in vivo. However, in the immediate environment of the organism there appears to be a localised loss of mucus gel structure. The mucus barrier is compromised if H. pylori associated gastric atrophy or peptic ulceration follows.

Preliminary characterization of mucin from effusions of cleft palate patients.

Middle ear effusions from children undergoing myringotomy were classified into three groups-cleft palate, thick (mucoid), and thin (serous). Mucin was purified from each of the three groups using CsCI equilibrium density gradient centrifugation. Analysis of the cleft palate mucin on Sepharose CL-2B showed it was excluded and therefore of large molecular weight. It could be broken down into smaller glycopeptide units by proteolysis and these glycopeptides had, based on elution position, a larger hydrodynamic size than those from the thick mucin. Intrinsic viscosity measurements demonstrated that the intact mucins could be ranked in order of molecular space occupancy; cleft palate > thick > thin. Amino acid analysis showed the cleft palate mucin to have an amino acid composition similar to other mucins, with serine, threonine, and proline constituting 41% by weight of the protein core. Thiol analysis gave evidence of a possible difference in polymerization between the three mucins, in that thin (the smallest mucin) contained the lowest number of thiols. This preliminary analysis of cleft palate mucin suggests a mucin with larger glycopeptide units forming an intact mucin of larger hydrodynamic size than either thick or thin middle ear mucins from anatomically normal children.