Biochemical definition of human tracheobronchial mucus

Tracheobronchial mucus is a heterogeneous milieu produced by several cell types. It has viscoelastic properties related to the organization of macromolecular components such as glycoproteins, proteins, lipids and nucleic acids. Proteins comprise components antigenically related to plasma proteins and secretory proteins such as kallicrein, lysozyme, amylase, bronchotransferrin, immunoglobulins A and proline-rich polypeptides. Tracheobronchial mucus also contains protease inhibitors and, in pathological conditions, important amounts of protease. Mucins, which are glycoproteins with a very rich carbohydrate content, represent another complex and major group of tracheobronchial molecules.     

Analyses of human colonic mucus obtained by an in vivo sampling technique

BackgroundThe mucus layer is an important dynamic component of the epithelial barrier. It contains mucin glycoproteins and other compounds secreted by the intestinal epithelium, such as secretory IgA. However, a standardized in vivo sampling technique of mucus in humans is not yet available.AimTo assess the validity and feasibility of mucin and protein determinations in human colonic mucus collected under physiological conditions.Subjects and methodsTriplicate colonic mucus samples were collected in 11 healthy volunteers using cytology brushes during sigmoidoscopy. As an indication of the quantity of collected mucus, total protein and mucin concentrations were determined by measuring oligosaccharide equivalents and monosaccharides. Also secretory IgA and sialic acid concentrations were determined and proteomic analysis was performed using surface enhanced laser desorption/ionization-time of flight-mass spectrometry.ResultsMean values of secretory IgA and sialic acid corrected for the amount of mucus ranged from 0.16 to 1.81 g secretory IgA/mmol oligosaccharide equivalents and from 12.6 to 48.6 g sialic acid/mmol oligosaccharide equivalents. Proteomic analysis of mucus is feasible and cluster analysis showed subject specific profiles.ConclusionUsing cytology brushes, human colonic mucus can be sampled and under physiological conditions. These samples could give information on the composition and quality of the mucus layer.     

An immunocytochemical/histochemical approach to tracheobronchial mucus characterization in the rabbit

Monoclonal antibodies have been made against components of rabbit respiratory mucous secretions, and these were used to localize secretory products in the respiratory epithelium by immunocytochemical methods. The antigen recognized by one antibody was localized within granules of mucous cells containing sulfated glycoprotein. This antibody also reacted with the ciliated surface layer of upper respiratory airways and mucous cells of colonic epithelium. However, only a subset of respiratory mucous cells containing sulfated glycoprotein, as determined by histochemistry, reacted with this monoclonal antibody. Other antibodies also recognized antigens on the ciliated surface of the rabbit respiratory tree but not in intracellular mucus. Thus, a library of monoclonal antibodies made against respiratory mucous secretions should represent an effective approach to defining the mucous lining of normal and diseased respiratory airways.     

Continuous absorbable suture technique for tracheobronchial sleeve resections

From January 2000, we changed from the traditional interrupted suture technique for tracheobronchial sleeve resections to a continuous suture technique with absorbable suture. This retrospective study reviewed our experience in the first 50 consecutive patients operated on between January 2000 and August 2006. The median age was 61 years (range, 30 to 80 years). There were 35 men and 15 women, 49 had malignant disease, and 1 had a benign tumor. Two patients had tracheal resection without removal of lung parenchyma; all others underwent sleeve lobectomy. There was 1 (2%) operative death due to pneumonia, and 8 (16%) postoperative complications including atrial fibrillation, lobar atelectasis, prolonged parenchymal air leak, empyema, paralytic ileus, and chylothorax. There was no anastomotic dehiscence or bronchopleural fistula. None of the patients developed stricture at the anastomotic site when followed up for a mean duration of 18.6 months. The continuous suture technique is easy to perform and the results are comparable with those of the interrupted suture technique. The use of absorbable suture appears to reduce the incidence of stricture at the anastomotic site.     

Fate of human albumin microsphere and spherocyte radioaerosols in the human tracheobronchial tree

Human albumin microspheres (^99mTc-HAM; 7–25μm) and spherocytes (^99mTc-S; 4–4.5μ) are particles used for lung mucociliary clearance (MCC) measurements. If radiolabelled HAM aerosols are sent through an airway model to a screen, they appear peripherally distributed, whereas S present a more central and homogeneous distribution. The radioscanning evaluation of particle sedimentation in saline-filled tubes shows quite a different behavior pattern for S, HAM, and surfactant-coated HAM (S-C HAM). In these experimental conditions, S-C HAM and HAM floating properties were better than those of S. This could be explained by physicalchemical factors. Looking for the fate of organic particles after inhalation, we performed multiple bronchial biopsies in seven bronchitic patients, 2 h following inhalation of HAM and S. Scanning electron microscopy revealed that most of S was floating on the mucus layer, while HAM appeared deeply imbedded inside the mucus and partially digested. The same study performed on three bronchitic patients after S-C HAM inhalation, shows that S-C HAM float like S. In vitro, the time-course of tryptic digestion is similar for HAM and for S. However, in vivo, the different location of each particle on the bronchial surface might lead to a different digestion by trypsin and by PZ-peptidase, which are dosable in pathologic mucus. In our opinion, if HAM are coated with surfactant, this should improve the mucus-HAM interaction, thus helping to control variability in lung radioaerosol MCC studies.     

Studies in rheology of human diabetes mellitus

Summary The rheology of blood cells studied intravascularly, and the relation between blood cells and endothelium was analyzed in vivo by high resolution, vital microscopy in four diabetic patients with varying duration of the disease. In a dipedicled, tubed skin-flap a titanium chamber with optics was implanted. A thin layer of tissue in this chamber was observed microscopically over a period of up to 4 months. Microvascular structure and function were analyzed under normal flow conditions as well as in various test situations with reduced or completely blocked flow in lipaemia and when slight local tissue trauma was added. It was found, contrary to what has hitherto been considered in the literature, that there is no aggregation of blood cells in diabetes, unless the metabolic balance is heavily upset as in acidosis. The rheology of the various types of blood cells is normal even in long-standing diabetes.Supported by grants from Swedish Diabetic Association, Swedish Medical Research Council and Swedish National Association against Heart and Chest Diseases.     

Hypothyroidism and the influence on human blood rheology

Viscoelastic properties of human whole blood were measured in 338 subjects: 110 persons (75 F, 35 M) following total thyroidectomy but without substitution therapy over three weeks as well as 228 healthy control subjects (124 F, 104 M) were investigated in this study. Subjects with other variable factors were excluded. The viscous and the elastic portion of apparent whole blood viscosity -the latter subdivided into red cell aggregation and red cell rigidity were determined by using a newly developed oscillating capillary rheometer and densitymeter at the real hematocrit value and at a computed hematocrit of 40%. Serum viscosity, hematocrit (Hct), hemoglobin (Hb), mean corpuscular volume of red blood cells (MCV), free triiodothyronine (fT3), free thyroxine (fT4) and serum-thyrotropin (bTSH) were evaluated as well. In a further subgroup of 80 subjects (40 patients with hypothyroidism, 40 healthy control persons) additional plasma viscosity and sedimentation rate were determined. Red cell aggregation and blood viscosity especially at shear-rates below 10/sec increased significantly in hypothyroid patients. There was no significant difference of red cell rigidity, serum viscosity, plasma viscosity and sedimentation rate as against euthyroids. So new aspects of thyroid dysfunction could be described probably with consequences for therapy and for considerations about the development of atherosclerosis and ischemic disorders.     

多层螺旋CT支气管图像后处理技术在诊断气管支气管结核中的价值

目的 通过多层螺旋CT(MSCT)扫描,探讨MSCT支气管图像后处理技术在气管支气管结核(TBTB)诊断中的价值。方法 回顾性收集2018年6—12月期间在陕西省结核病防治院因临床症状或MSCT轴面图像高度怀疑TBTB并行MSCT扫描和支气管镜检查的患者117例,所有患者轴面图像均行MSCT支气管图像后处理,并经支气管镜检查,在镜下获取组织标本送病理科进行病理检查,最终确诊TBTB患者69例,非TBTB患者48例。以支气管镜及活检病理检查的诊断结果作为参考标准,评价MSCT支气管图像后处理技术对TBTB诊断的敏感度、特异度和符合率,并采用一致性检验来评价2名影像科医师对该疾病诊断的一致性。结果 以支气管镜病理活检结果为参考标准,MSCT支气管图像后处理技术诊断TBTB的敏感度、特异度、符合率分别为97.10%(67/69)、43.75%(21/48)、75.21%(88/117),一致性分析结果显示,Kappa值为0.44,95%CI:0.29~0.60;2名影像科医师通过该技术处理后的图像对TBTB诊断的一致性较好(Kappa值为0.81,95%CI:0.68~0.93)。结论 MSCT支气管图像后处理技术对TBTB有较好的诊断价值。     

Long-lasting effects on rheology and clearance of bronchial mucus after short-term administration of high doses of carbocysteine-lysine to patients with chronic bronchitis

The rheological behavior and clearance of bronchial mucus samples collected by protected expectoration from 24 out-patients with simple chronic bronchitis were investigated before, at the end of a short period of treatment (4 days) with a single oral dose of 2.7 g (sachet) of carbocysteine-lysine (evening meal), and on the 4th and 8th days after the end of treatment versus placebo. In the group treated with carbocysteine-lysine, there were significant reductions in viscosity (-67, -48, -62%) and increases in mucociliary transport (+41, +31, +34%) at the three times mentioned. The most striking finding was that the improvements were still present 8 days after cessation of treatment. The elasticity parameter was not affected in any statistically significant way (-10, -24, +65%). These findings suggest the presence of some type of 'post-mucoactive' effect.     

Pulmonary and tracheobronchial amyloidosis

Amyloidosis is a collection of diseases in which different proteins are deposited as insoluble beta-pleated sheets, disrupting organ function. Each precursor protein induces a separate spectrum of organ involvement, and different disease manifestations within the lung. Although autopsy data often demonstrate amyloid deposits in various compartments of the lung, few of the pathologic findings are expressed clinically. We review the pulmonary pathology, radiology, clinical presentations, and treatment options for each of the major systemic and localized forms of amyloidosis. This review focuses on amyloid derived from immunoglobulin light-chain protein (AL disease), which most frequently involves the lung in both systemic and localized forms of the disease. Manifestations of AL-related lung disease range from nodules identified on incidental chest films to diffuse alveolar+-septal deposition mimicking diffuse alveolar damage. We discuss respiratory failure due to diaphragm invasion, proximal tracheal disease, and diffuse alveolar-septal deposition. Guidelines for evaluation of patients with amyloid are presented.     

Catheter jet ventilation, a favorable technique during resection of the central tracheobronchial system

Experience with catheter jet ventilation as an optimal ventilation technique during the critical phase of resection in the region of the central tracheobronchial system (bifurcational resections, extended resections in the bifurcational region) in 9 patients is described. For this technique we use a simple and cheap system consisting of a pressure-reduction valve, an interruption valve manually worked with a pistol handle, 2 manometers and a thin plastic catheter as a jet. In 8 cases the anesthesiologic management during the jet ventilation phase, ranging between 35 and 150 minutes, was without any problem; the one complication and the possible way of solving similar accidents are discussed. In comparison with the conventional technique, catheter jet ventilation gives the surgeon the possibility of complete freedom of action during suturing of the airway anastomosis.     

Sampling the N-terminal proteome of human blood

The proteomes of blood plasma and serum represent a potential gold mine of biological and diagnostic information, but challenges such as dynamic range of protein concentration have hampered efforts to unlock this resource. Here we present a method to label and isolate N-terminal peptides from human plasma and serum. This process dramatically reduces the complexity of the sample by eliminating internal peptides. We identify 772 unique N-terminal peptides in 222 proteins, ranging over six orders of magnitude in abundance. This approach is highly suited for studying natural proteolysis in plasma and serum. We find internal cleavages in plasma proteins created by endo- and exopeptidases, providing information about the activities of proteolytic enzymes in blood, which may be correlated with disease states. We also find signatures of signal peptide cleavage, coagulation and complement activation, and other known proteolytic processes, in addition to a large number of cleavages that have not been reported previously, including over 200 cleavages of blood proteins by aminopeptidases. Finally, we can identify substrates from specific proteases by exogenous addition of the protease combined with N-terminal isolation and quantitative mass spectrometry. In this way we identified proteins cleaved in human plasma by membrane-type serine protease 1, an enzyme linked to cancer progression. These studies demonstrate the utility of direct N-terminal labeling by subtiligase to identify and characterize endogenous and exogenous proteolysis in human plasma and serum.     

Rapid transport of large polymeric nanoparticles in fresh undiluted human mucus

Nanoparticles larger than the reported mesh-pore size range (10-200 nm) in mucus have been thought to be much too large to undergo rapid diffusional transport through mucus barriers. However, large nanoparticles are preferred for higher drug encapsulation efficiency and the ability to provide sustained delivery of a wider array of drugs. We used high-speed multiple-particle tracking to quantify transport rates of individual polymeric particles of various sizes and surface chemistries in samples of fresh human cervicovaginal mucus. Both the mucin concentration and viscoelastic properties of these cervicovaginal samples are similar to those in many other human mucus secretions. Unexpectedly, we found that large nanoparticles, 500 and 200 nm in diameter, if coated with polyethylene glycol, diffused through mucus with an effective diffusion coefficient (D(eff)) only 4- and 6-fold lower than that for the same particles in water (at time scale tau = 1 s). In contrast, for smaller but otherwise identical 100-nm coated particles, D(eff) was 200-fold lower in mucus than in water. For uncoated particles 100-500 nm in diameter, D(eff) was 2,400- to 40,000-fold lower in mucus than in water. Much larger fractions of the 100-nm particles were immobilized or otherwise hindered by mucus than the large 200- to 500-nm particles. Thus, in contrast to the prevailing belief, these results demonstrate that large nanoparticles, if properly coated, can rapidly penetrate physiological human mucus, and they offer the prospect that large nanoparticles can be used for mucosal drug delivery.