Effect of biochemical components on rheologic properties of nasal mucus in chronic sinusitis

Eosinophilic mucus diseases

Eosinophilic inflammation is primarily characterized by type 2 immune responses against parasitic organisms. In the contemporary human being especially in developed countries, eosinophilic inflammation is strongly associated with allergic/sterile inflammation, and constitutes an undesired immune reaction. This situation is in stark contrast to neutrophilic inflammation, which is indispensable for the host defense against bacterial infections. Among eosinophilic inflammatory disorders, massive accumulation of eosinophils within mucus is observed in certain cases, and is often linked to the distinctive clinical finding of mucus with high viscosity. Eosinophilic mucus is found in a variety of diseases, including chronic allergic keratoconjunctivitis, chronic rhinosinusitis encompassing allergic fungal sinusitis, eosinophilic otitis media, eosinophilic sialodochitis, allergic bronchopulmonary aspergillosis/mycosis, eosinophilic plastic bronchitis, and eosinophilic asthma. In these pathological conditions, chronic inflammation and tissue remodeling coupled with irreversible organ damage due to persistent adhesion of toxic substances and luminal obstruction may impose a significant burden on the body. Eosinophils aggregate in the hyperconcentrated mucus together with cell-derived crystals, macromolecules, and polymers, thereby affecting the biophysical properties of the mucus. This review focuses on the clinically significant challenges of mucus and discusses the consequences of activated eosinophils on the mucosal surface that impact mucus and persistent inflammation.

Emerging cell and molecular targets for treating mucus hypersecretion in asthma

Mucus provides a protective barrier that is crucial for host defense in the lungs. However, excessive or abnormal mucus can have pathophysiological consequences in many pulmonary diseases, including asthma. Patients with asthma are treated with agents that relax airway smooth muscle and reduce airway inflammation, but responses are often inadequate. In part, this is due to the inability of existing therapeutic agents to directly target mucus. Accordingly, there is a critical need to better understand how mucus hypersecretion and airway plugging are affected by the epithelial cells that synthesize, secrete, and transport mucus components. This review highlights recent advances in the biology of mucin glycoproteins with a specific focus on MUC5AC and MUC5B, the chief macromolecular components of airway mucus. An improved mechanistic understanding of key steps in mucin production and secretion will help reveal novel potential therapeutic strategies.

Nasal Model Experiments Show That a Collimated Fluid Delivers Precise Doses to the Human Olfactory Cavity in the Side-Laying Position

The nasal administration of therapeutic fluids and vaccines is used to treat allergic rhinitis, sinusitis, congestion, coronaviruses and even Alzheimer's disease. In the latter, the drug must reach the olfactory region, so it finds its way into the central nervous system. Effective administration techniques able to reach the olfactory region are challenging due to the tortuous anatomy of the nasal cavity, and are frequently evaluated in vitro using transparent anatomical models. Here, the liquid distribution inside a 3D printed human nasal cavity is quantified for model fluids resulting from the discharge of a 1-mL syringe with either a spray-generating nozzle, and a straight tip emitting a collimated fluid stream. Experiments using two model fluids with different viscosities suggest that a simple, correctly positioned straight tip attached to a syringe is able to efficiently deliver most of a therapeutic fluid in the human olfactory region in the side-laying position, avoiding the adoption of head-back and head-down positions that can be difficult for patients in the age range typical of Alzheimer's disease. Furthermore, we demonstrate by computer simulations that the conclusion is valid within a wide range of parameters.

Morphogenesis of bacterial colonies in polymeric environments

Many bacteria live in polymeric fluids, such as mucus, environmental polysaccharides, and extracellular polymers in biofilms. However, lab studies typically focus on cells in polymer-free fluids. Here, we show that interactions with polymers shape a fundamental feature of bacterial life-how they proliferate in space in multicellular colonies. Using experiments, we find that when polymer is sufficiently concentrated, cells generically and reversibly form large serpentine "cables" as they proliferate. By combining experiments with biophysical theory and simulations, we demonstrate that this distinctive form of colony morphogenesis arises from an interplay between polymer-induced entropic attraction between neighboring cells and their hindered ability to diffusely separate from each other in a viscous polymer solution. Our work thus reveals a pivotal role of polymers in sculpting proliferating bacterial colonies, with implications for how they interact with hosts and with the natural environment, and uncovers quantitative principles governing colony morphogenesis in such complex environments.

Development of an Intranasal Gel for the Delivery of a Broadly Acting Subunit Influenza Vaccine

Influenza virus is a major cause of death on a global scale. Seasonal vaccines have been developed to combat influenza; however, they are not always highly effective. One strategy to develop a more broadly active influenza vaccine is the use of multiple rounds of layered consensus buildings to generate recombinant antigens, termed computationally optimized broadly reactive antigen (COBRA). Immunization with the COBRA hemagglutinin (HA) can elicit broad protection against multiple strains of a single influenza subtype (e.g., H1N1). We formulated a COBRA H1 HA with a stimulator of interferon genes agonist cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) into a nasal gel for vaccination against influenza. The gel formulation was designed to increase mucoadhesion and nasal retention of the antigen and adjuvant to promote a strong mucosal response. It consisted of a Schiff base-crosslinked hydrogel between branched polyethyleneimine and oxidized dextran. Following a prime-boost-boost schedule, an intranasal gel containing cGAMP and model antigen ovalbumin (OVA) led to the faster generation of serum IgG, IgG1, and IgG2c and significantly greater serum IgG1 levels on day 42 compared to soluble controls. Additionally, OVA-specific IgA was detected in nasal, vaginal, and fecal samples for all groups, except the vehicle control. When the COBRA HA was given intranasally in a prime-boost schedule, the mice receiving the gel containing the COBRA and cGAMP had significantly higher serum IgG and IgG2c at day 41 compared to all groups, and only this group had IgA levels above the background in vaginal, nasal, and fecal samples. Overall, this study indicates the utility of an intranasal gel for the delivery of COBRAs for the generation of serum and mucosal humoral responses.

Mucins Inhibit Coronavirus Infection in a Glycan-Dependent Manner

Mucins are a diverse and heterogeneous family of glycoproteins that comprise the bulk of mucus and the epithelial glycocalyx. Mucins are intimately involved in viral transmission. Mucin and virus laden particles can be expelled from the mouth and nose to later infect others. Viruses must also penetrate the mucus layer before cell entry and replication. The role of mucins and their molecular structure have not been well-characterized in coronavirus transmission studies. Laboratory studies predicting high rates of fomite transmission have not translated to real-world infections, and mucins may be one culprit. Here, we probed both surface and direct contact transmission scenarios for their dependence on mucins and their structure. We utilized disease-causing, bovine-derived, human coronavirus OC43. We found that bovine mucins could inhibit the infection of live cells in a concentration- and glycan-dependent manner. The effects were observed in both mock fomite and direct contact transmission experiments and were not dependent upon surface material or time-on-surface. However, the effects were abrogated by removal of the glycans or in a cross-species infection scenario where bovine mucin could not inhibit the infection of a murine coronavirus. Together, our data indicate that the mucin molecular structure plays a complex and important role in host defense.

In situ-gelling starch nanoparticle (SNP)/O-carboxymethyl chitosan (CMCh) nanoparticle network hydrogels for the intranasal delivery of an antipsychotic peptide

Existing oral or injectable antipsychotic drug delivery strategies typically demonstrate low bioavailability to targeted brain regions, incentivizing the development of alternative delivery strategies. Delivery via the nasal cavity circumvents multiple barriers for reaching the brain but requires drug delivery vehicles with very specific properties to be effective. Herein, we report in situ-gelling and degradable bulk nanoparticle network hydrogels consisting of oxidized starch nanoparticles (SNPs) and carboxymethyl chitosan (CMCh) that enable intranasal delivery via spray, high nasal mucosal retention, and functional controlled release of the peptide drug PAOPA, a positive allosteric modulator of dopamine D2 receptor. PAOPA-loaded SNP-CMCh hydrogels can alleviate negative symptoms like behavioural abnormalities associated with schizophrenia (i.e. decreased social interaction time) for up to 72 h in an MK-801-induced pre-clinical rat model of schizophrenia at a low drug dosage (0.5 mg/kg); in comparison, conventional PAOPA administration via the intraperitoneal route requires twice the PAOPA dose to achieve a therapeutic effect that persists for only a few hours. This strategy offers potential for substantially decreasing re-administration frequencies and overall drug doses (and thus side-effects) of a range of potential antipsychotic drugs via a minimally-invasive administration route.

Computational fluid dynamics simulation to compare large volume irrigation and continuous spraying during nasal irrigation

BACKGROUND

Nasal irrigation is now widely recognized as a treatment for chronic rhinosinusitis and during the postoperative period. However, there are no guidelines for performing irrigation. This study used computational fluid dynamics (CFD) simulation objective physical parameters to optimize and increase the efficiency of nasal irrigation and to compare large-volume, manual, and gravity pressure irrigation vs small-volume continuous spraying.

METHODS

A 3-dimensional (3D) sinonasal model was constructed from a healthy adult high-resolution computed tomography (CT) scan. The 3D nasal model was constructed using a tetrahedral and hex-dominant mesh grid with TGRID™ 16 (ANSYS Inc., Villeurbanne, France) software. A structured hex mesh was created inside the domain using the Hexcore meshing method. The final mesh had a total of 9.6 × 10⁶ cells with an average size of 0.29 mm³ , or an average volume of 2.42 × 10^-2 mm³ . Navier-Stokes equations were resolved with the standard k - ε  model.

RESULTS

Large-volume irrigation (15 mL/s) covered all zones (136 to 310 cm² ) rapidly with strong shear stress and prolonged contact time (310 mPa 3.26 seconds for gravity mode and 280 mPa 3.35 seconds for manual pressure mode). Continuous spraying (3 mL/second) covered all areas (76 to 310 cm² ) but with far less volume, more slowly, with low shear stress (50 mPa), and with shorter contact time (1.84 seconds). The surface wetted by time in contact was 135.4, 113.9, and 46.6 cm² for gravity, manual pressure mode, and continuous spraying, respectively.

CONCLUSION

CFD simulation visualizes the circulation of water during nasal irrigation and makes it possible to determine objective parameters to decide which mode of irrigation may be used.

Glycan-immobilized dual-channel field effect transistor biosensor for the rapid identification of pandemic influenza viral particles

Pandemic influenza, triggered by the mutation of a highly pathogenic avian influenza virus (IFV), has caused considerable damage to public health. In order to identify such pandemic IFVs, antibodies that specifically recognize viral surface proteins have been widely used. However, since the analysis of a newly discovered virus is time consuming, this delays the availability of suitable detection antibodies, making this approach unsuitable for the early identification of pandemic IFVs. Here we propose a label-free semiconductor-based biosensor functionalized with sialic-acid-containing glycans for the rapid identification of the pandemic IFVs present in biological fluids. Specific glycans are able to recognize wild-type human and avian IFVs, suggesting that they are useful in discovering pandemic IFVs at the early stages of an outbreak. We successfully demonstrated that a dual-channel integrated FET biosensing system, which were modified with 6′-sialyllactose and 3′-sialyllactose for each gate area, can directly and specifically detect human H1N1 and avian H5N1 IFV particles, respectively, present in nasal mucus. Furthermore, to examine the possibility of identifying pandemic IFVs, the signal attributed to the detection of Newcastle disease virus (NDV) particles, which was selected as a prime model of a pandemic IFV, was clearly observed from both sensing gates. Our findings suggest that the proposed glycan-immobilized sensing system could be useful in identifying new pandemic IFVs at the source of an outbreak.

Altered Viscosity of Nasal Secretions in Postnasal Drip

BACKGROUND

Postnasal drip (PND) is a common symptom associated with upper respiratory tract disorders. It occurs without other symptoms or combined with chronic rhinosinusitis. However, the pathophysiology of PND is debated to this day, and an objective definition of PND has not been established. Therefore, we aimed to elucidate whether the viscosity and volume of nasal secretions as well as the mucociliary clearance and sensitivity of the nasopharynx, or atopy could play a role in the pathophysiology of PND.

METHODS

A prospective case-control study of 30 patients (15 patients with PND and 15 healthy subjects) was conducted. The viscosity and volume of nasal secretions, the nasopharyngeal sensitivity, the mucociliary clearance, and allergic sensitization using a skin prick test were assessed in all subjects.

RESULTS

Viscosity of nasal secretions in patients with PND was significantly increased compared with healthy subjects. Two follow-up measurements in symptom-free intervals showed reversibility of increased viscosity. Analysis of nasopharyngeal sensitivity showed significant reductions in patients with PND. Furthermore, mucociliary clearance seems to be prolonged in patients with PND. The volume of nasal secretions and the atopy screening showed no significant differences in patients with PND compared with healthy individuals.

CONCLUSIONS

Increased viscosity seems to play a relevant role in the pathophysiology of PND. Additionally, delayed mucociliary clearance and hyposensitivity of the nasopharynx may be further components. Earlier concepts of PND, regarding an increased volume of secretions and atopy, do not seem to hold true because our analyses showed no significant difference between cases and control subjects.

The Hypotonic Environmental Changes Affect Liposomal Formulations for Nose-to-Brain Targeted Drug Delivery

Systemic administration of drugs is ineffective in the treatment of central nervous system disorders because of the blood-brain barrier. Nasal administration has been suggested as an alternative administration route as drugs absorbed in the olfactory epithelium bypass the blood-brain barrier and reach the brain within minutes. However, the nasal mucosa properties (e.g., tonicity, pH) are not constant because of physiological and environmental factors, and this might limit the therapeutic outcome of nanocarrier-based formulations. To shine light on the impact of environmental ionic strength on nanocarrier-based formulations, we have studied how liposomal formulations respond to the change of tonicity of the external environment. Large unilamellar vesicles loaded with 6 different drugs were exposed to different hypotonic environments, creating an osmotic gradient within the inner core and external environment of the liposomes up to 650 mOsm/kg. Both size and polydispersity of liposomes were significantly affected by tonicity changes. Moreover, the release kinetics of hydrophilic and lipophilic drugs were largely enhanced by hypotonic environments. These results clearly demonstrate that the environmental ionic strength has an impact on liposomal formulation stability and drug release kinetics and it should be considered when liposomal formulations for nose-to-brain targeted drug delivery are designed.

How to characterize a nasal product. The state of the art of in vitro and ex vivo specific methods

Nasal delivery offers many benefits over other conventional routes of delivery (e.g. oral or intravenous administration). Benefits include, among others, a fast onset of action, non-invasiveness and direct access to the central nervous system. The nasal cavity is not only limited to local application (e.g. rhinosinusitis) but can also provide direct access to other sites in the body (e.g. the central nervous system or systemic circulation). However, both the anatomy and the physiology of the nose impose their own limitations, such as a small volume for delivery or rapid mucociliary clearance. To meet nasal-specific criteria, the formulator has to complete a plethora of tests, in vitro and ex vivo, to assess the efficacy and tolerance of a new drug-delivery system. Moreover, depending on the desired therapeutic effect, the delivery of the drug should target a specific pathway that could potentially be achieved through a modified release of this drug. Therefore, this review focuses on specific techniques that should be performed when a nasal formulation is developed. The review covers both the tests recommended by regulatory agencies (e.g. the Food and Drug Administration) and other complementary experiments frequently performed in the field.

Mucociliary Defense: Emerging Cellular, Molecular, and Animal Models

Respiratory tissues are bombarded by billions of particles daily. If allowed to accumulate, these particles can cause injury, inflammation, or infection, and thus may significantly disrupt airflow and gas exchange. Mucociliary defense, a primary mechanism for protecting host tissues, operates through the coordinated functions of mucus and cilia that trap and eliminate inhaled materials. Mucociliary function is also required for the elimination of endogenous cells and debris. Although defense is necessarily robust, it is also tightly regulated to minimize physiologic disruption of the host. Indeed, mucociliary dysfunction contributes to the pathogenesis of many lung diseases-including asthma, chronic obstructive pulmonary disease, pulmonary fibrosis, and cystic fibrosis-in which airflow limitation, inflammation, persistent tissue injury, and structural remodeling occur. Here, we highlight recent advances in cilia and mucin biology, the importance of well-controlled mucociliary interactions, and the need to better understand how these regulate innate barrier and immune defense.

Tailoring Formulations for Intranasal Nose-to-Brain Delivery: A Review on Architecture, Physico-Chemical Characteristics and Mucociliary Clearance of the Nasal Olfactory Mucosa

The blood-brain barrier and the blood-cerebrospinal fluid barrier are major obstacles in central nervous system (CNS) drug delivery, since they block most molecules from entering the brain. Alternative drug delivery routes like intraparenchymal or intrathecal are invasive methods with a remaining risk of infections. In contrast, nose-to-brain delivery is a minimally invasive drug administration pathway, which bypasses the blood-brain barrier as the drug is directed from the nasal cavity to the brain. In particular, the skull base located at the roof of the nasal cavity is in close vicinity to the CNS. This area is covered with olfactory mucosa. To design and tailor suitable formulations for nose-to-brain drug delivery, the architecture, structure and physico-chemical characteristics of the mucosa are important criteria. Hence, here we review the state-of-the-art knowledge about the characteristics of the nasal and, in particular, the olfactory mucosa needed for a rational design of intranasal formulations and dosage forms. Also, the information is suitable for the development of systemic or local intranasal drug delivery as well as for intranasal vaccinations.

Role of mucins in lung homeostasis: regulated expression and biosynthesis in health and disease

In humans and mice, the first line of innate defense against inhaled pathogens and particles in the respiratory tract is airway mucus. The primary solid components of the mucus layer are the mucins MUC5AC and MUC5B, polymeric glycoproteins whose changes in abundance and structure can dramatically affect airway defense. Accordingly, MUC5AC/Muc5ac and MUC5B/Muc5b are tightly regulated at a transcriptional level by tissue-specific transcription factors in homeostasis and in response to injurious and inflammatory triggers. In addition to modulated levels of mucin gene transcription, translational and post-translational biosynthetic processes also exert significant influence upon mucin function. Mucins are massive macromolecules with numerous functional domains that contribute to their structural composition and biophysical properties. Single MUC5AC and MUC5B apoproteins have molecular masses of >400 kDa, and von Willebrand factor D-like as well as other cysteine-rich domain segments contribute to mucin polymerization and flexibility, thus increasing apoprotein length and complexity. Additional domains serve as sites for O-glycosylation, which increase further mucin mass several-fold. Glycosylation is a defining process for mucins that is specific with respect to additions of glycans to mucin apoprotein backbones, and glycan additions influence the physical properties of the mucins via structural modifications as well as charge interactions. Ultimately, through their tight regulation and complex assembly, airway mucins follow the biological rule of 'form fits function' in that their structural organization influences their role in lung homeostatic mechanisms.

Reversal of Chronic Rhinosinusitis-Associated Sinonasal Ciliary Dysfunction

Background

Although multiple etiologies contribute to the development of chronic rhinosinusitis (CRS), a common pathophysiological sequelae is ineffective sinonasal mucociliary clearance, leading to stasis of sinonasal secretions, with subsequent infection and/or persistent inflammation. Proper therapeutic intervention typically restores mucociliary activity, suggesting that the pathophysiological process(es) responsible for CRS-associated mucostasis may be reversible. We previously demonstrated a blunted response of CRS sinonasal cilia after purinergic stimulation. This study investigated whether the blunted ciliary response is unique to purinergic stimulation and addressed whether the blunted effect is primarily caused by local CRS-associated mediators or inherent genetic defects in ciliary function.

Methods

A dual temperature-controlled perfusion chamber, differential interference contrast microscopy, and high-speed digital video were used to analyze both basal as well as cholinergic, adrenergic, and purinergic stimulation of cilia in human sinonasal mucosal explants. Additionally, enzymically dissociated sinonasal ciliated cells were maintained ex vivo in submersion, on glass coverslips, and assessed daily for purinergic ciliary beat frequency stimulation.

Results

Cholinergic and adrenergic stimulation generally were blunted in mucosal explants obtained from CRS patients. Ex vivo maintenance of samples demonstrated that the majority of CRS samples developed a stimulatory phenotype within 36 hours of culturing.

Conclusion

CRS is a common debilitating disease principally affecting sinonasal epithelial function with a resultant diminution of mucociliary transport. Presently, little is known about how this disease process affects the sinonasal epithelial ciliated cells. Our data suggest that ciliary response to environmental insults is blunted in a reversible manner in CRS patients.

A slippery slope: On the origin, role and physiology of mucus

The mucosa of the gastrointestinal tract, eyes, nose, lungs, cervix and vagina is lined by epithelium interspersed with mucus-secreting goblet cells, all of which contribute to their unique functions. This mucus provides an integral defence to the epithelium against noxious agents and pathogens. However, it can equally act as a barrier to drugs and delivery systems targeting epithelial passive and active transport mechanisms. This review highlights the various mucins expressed at different mucosal surfaces on the human body, and their role in creating a mucoid architecture to protect epithelia with specialized functions. Various factors compromising the barrier properties of mucus have been discussed, with an emphasis on how disease states and microbiota can alter the physical properties of mucus. For instance, Akkermansia muciniphila, a bacterium found in higher levels in the gut of lean individuals induces the production of a thickened gut mucus layer. The aims of this article are to elucidate the different physiological, biochemical and physical properties of bodily mucus, a keen appreciation of which will help circumvent the slippery slope of challenges faced in achieving effective mucosal drug and gene delivery.

Physicochemical properties of mucus and their impact on transmucosal drug delivery

Mucus is a selective barrier to particles and molecules, preventing penetration to the epithelial surface of mucosal tissues. Significant advances in transmucosal drug delivery have recently been made and have emphasized that an understanding of the basic structure, viscoelastic properties, and interactions of mucus is of great value in the design of efficient drug delivery systems. Mucins, the primary non-aqueous component of mucus, are polymers carrying a complex and heterogeneous structure with domains that undergo a variety of molecular interactions, such as hydrophilic/hydrophobic, hydrogen bonds and electrostatic interactions. These properties are directly relevant to the numerous mucin-associated diseases, as well as delivering drugs across the mucus barrier. Therefore, in this review we discuss regional differences in mucus composition, mucus physicochemical properties, such as pore size, viscoelasticity, pH, and ionic strength. These factors are also discussed with respect to changes in mucus properties as a function of disease state. Collectively, the review seeks to provide a state of the art roadmap for researchers who must contend with this critical barrier to drug delivery.

Active microrheology determines scale-dependent material properties of Chaetopterus mucus

We characterize the lengthscale-dependent rheological properties of mucus from the ubiquitous Chaetopterus marine worm. We use optically trapped probes (2-10 μm) to induce microscopic strains and measure the stress response as a function of oscillation amplitude. Our results show that viscoelastic properties are highly dependent on strain scale (l), indicating three distinct lengthscale-dependent regimes at l1 ≤4 μm, l2≈4-10 μm, and l3≥10 μm. While mucus response is similar to water for l1, suggesting that probes rarely contact the mucus mesh, the response for l2 is distinctly more viscous and independent of probe size, indicative of continuum mechanics. Only for l3 does the response match the macroscopic elasticity, likely due to additional stiffer constraints that strongly resist probe displacement. Our results suggest that, rather than a single lengthscale governing crossover from viscous to elastic, mucus responds as a hierarchical network with a loose biopolymer mesh coupled to a larger scaffold responsible for macroscopic gel-like mechanics.

Sinonasal Mucociliary Clearance in Health and Disease

Although much has been elucidated in the past 170 years concerning the precise mechanism of ciliary function in the healthy or diseased human respiratory system, significant questions remain. The first description of ciliary action is credited to Sharpey in 1835. However, the importance of mucosal function was not apparent until Hilding's investigations of the postsurgical canine sinus demonstrated scar formation and disruption of mucociliary clearance. Subsequently, several techniques for mucosal coverage of exposed bone, most notably by Sewall and Boyden, were reported. The underlying physiology explaining the importance of the mucosa and the concept of mucosal preservation became apparent with the description of the sinonasal mucociliary flow patterns by Messerklinger; and thus the restoration of natural sinus physiology, ie, mucociliary clearance, became the goal of both medical and surgical treatment of sinonasal inflammatory disease. Clearance of benign and pathological substances in the mucus is governed by the propulsive force of the beating cilia and the physical characteristics of the overlying mucus. The respiratory cilia continually beat in a coordinated fashion, and in times of stress (eg, exercise, infection, or fever) ciliary beat frequency increases to accelerate mucus clearance. Thus, upper airway ciliary motility is under dynamic modulation. Multiple investigations incontrovertibly demonstrate a marked decrease in sinonasal mucociliary clearance in patients with chronic rhinosinusitis. Possible explanations for this finding are 1) a reduced basal ciliary beat frequency, 2) an alteration of the viscoelastic properties of airway secretions, and/or 3) a blunted dynamic response of sinonasal cilia to environmental stimuli. Studies of the first two explanations yield conflicting results, and to date, the third possibility remains uninvestigated. A review of the current understanding of the cellular regulation of respiratory ciliary activity and its contribution to chronic rhinosinusitis is presented.

Development of a physiologically relevant dripping analytical method using simulated nasal mucus for nasal spray formulation analysis

Current methods for nasal spray formulations have been elementary evaluating the dripping characteristics of a formulation and have not assessed the behavior of the nasal formulation in the presence of varying types of mucus depending on the indication or diseased state. This research investigated the effects of nasal mucus on the dripping behavior of nasal formulations and focused on developing an improved in vitro analytical test method that is more physiologically relevant in characterizing nasal formulation dripping behavior. Method development was performed using simulated nasal mucus preparations for both healthy and diseased states as coatings for the dripping experiment representing a wide range of viscosity. Factors evaluated during development of this in vitro test method included amount of mucus, application of mucus, drying times, and compatibility of the mucus on a C₁₈ Thin Layer Chromatography (TLC) substrate. The dripping behavior of nasal formulations containing a range of 1% Avicel to 3.5% Avicel was assessed by actuating the nasal spray on a perpendicular TLC plate coated with either healthy or diseased simulated nasal mucus. After actuation of the nasal spray, the dripping of the formulation on the coated TLC plate was measured after the plate was repositioned vertically. The method that was developed generated reproducible results on the dripping behavior of nasal formulations and provided critical information about the compatibility of the formulation with the nasal mucus for different diseased states, aiding in nasal spray formulation development and physical characterization of the nasal spray.

Mechanics regulates ATP-stimulated collective calcium response in fibroblast cells

Cells constantly sense their chemical and mechanical environments. We study the effect of mechanics on the ATP-induced collective calcium response of fibroblast cells in experiments that mimic various tissue environments. We find that closely packed two-dimensional cell cultures on a soft polyacrylamide gel (Young's modulus E = 690 Pa) contain more cells exhibiting calcium oscillations than cultures on a rigid substrate (E = 36 000 Pa). Calcium responses of cells on soft substrates show a slower decay of calcium level relative to those on rigid substrates. Actin enhancement and disruption experiments for the cell cultures allow us to conclude that actin filaments determine the collective Ca(2+) oscillatory behaviour in the culture. Inhibition of gap junctions results in a decrease of the oscillation period and reduced correlation of calcium responses, which suggests additional complexity of signalling upon cell-cell contact. Moreover, the frequency of calcium oscillations is independent of the rigidity of the substrate but depends on ATP concentration. We compare our results with those from similar experiments on individual cells. Overall, our observations show that collective chemical signalling in cell cultures via calcium depends critically on the mechanical environment.

Past, present and future of macrolide therapy for chronic rhinosinusitis in Japan

In 1984, the effectiveness of low-dose, long-term erythromycin treatment (macrolide therapy) for diffuse panbronchiolitis (DPB) was first reported in Japan. The 5-year survival rate for DPB improved from 62.9 to 91.4% after implementation of macrolide therapy. The usefulness of this treatment has since been demonstrated in patients with other chronic airway diseases, such as chronic bronchitis, cystic fibrosis, bronchiectasis, bronchial asthma, and chronic rhinosinusitis (CRS). The new 14-membered macrolides clarithromycin and roxithromycin and the 15-membered macrolide azithromycin are also effective for treating these inflammatory diseases. The mechanism of action of the 14- and 15-membered macrolides may involve anti-inflammatory rather than anti-bacterial activities. Macrolide therapy is now widely used for the treatment of CRS in Japan; it is particularly effective for treating neutrophil-associated CRS and is useful for suppressing mucus hypersecretion. However, macrolide therapy is not effective for eosinophil-predominant CRS, which is characterized by serum and tissue eosinophilia, high serum IgE levels, multiple polyposis, and bronchial asthma. Recent reports have described the clinical efficacy of macrolides in treating other inflammatory diseases and new biological activities (e.g., anti-viral). New macrolide derivatives exhibiting anti-inflammatory but not anti-bacterial activity thus have therapeutic potential as immunomodulatory drugs. The history, current state, and future perspectives of macrolide therapy for treating CRS in Japan will be discussed in this review.

Surfactant proteins A, B, C and D in the human nasal airway: associated with mucosal glands and ciliated epithelium but absent in fluid-phase secretions and mucus

AIMS

To investigate the presence of surfactant protein (SP) A, B, C and D in nasal airways and to determine whether the proteins exert their main functions in nasal secretions or in the deeper layers of the nasal mucosa.

METHODS

Volunteers were recruited from the Department of ENT Head and Neck Surgery, Odense University Hospital, Denmark. The study included 39 subjects. Nasal mucosal biopsies were analyzed by immunohistochemistry, and bronchoalveolar and nasal lavages, nasal brush biopsies and nasal mucus were analyzed for SP-A, -B, -C and -D by SDS-PAGE and Western blotting. The presence of SP-A and SP-D in the first three samplings were also analyzed by enzyme-linked immunosorbent assay.

RESULTS

In nasal mucosal biopsies, SP-A, -B, -C and -D were all demonstrated in the serous acini of the submucosal glands and in the surface epithelium. SP-D was detected in nasal brush biopsies, whereas the other SPs were absent. Moreover, SP-A, -B, -C and -D were absent in nasal lavage and mucus.

CONCLUSION

SP-A, -B, -C and -D exert their protective effect in the ductal epithelium of the submucosal glands rather than in nasal secretions and mucus. Further studies are required to clarify the functions of these proteins in nasal secretory pathways for understanding upper airway diseases.

Effects of prednisone on mucociliary clearance in a murine model

All transplant patients are at increased risk of developing pulmonary infections, a significant cause of morbidity and mortality. Immunosuppressants increase the incidence of lung infection by acting not only directly on the inflammatory cells, but also on the native immune system. Experimental studies have shown corticosteroid therapy, which is used in most immunosuppressive protocols after transplantation, to suppress mucus production by inhibiting calceiform. The objective of this study was to evaluate the effects of prednisone on mucociliary clearance. A total of 120 male Wistar rats were distributed into 4 groups. Animals in P1, P2, and P3 groups received daily doses of prednisone (0.625, 1.25, and 2.5 mg/kg/d), and hosts in the Sal group underwent gavage with saline solution (2.5 mL/d). After 7, 15, and 30 days, treatment, animals were killed. We assessed ciliary beating frequency (CBF), mucociliary transport velocity (MCTV), and mucus transportability (MT). There was no significant difference for CBF regarding dose (P = .089) or treatment duration (P = .175). MCTV values of 0.60 ± 0.14 in group P1, 0.59 ± 0.13 in group P2, 0.51 ± 0.19 in group P3, and 0.61 ± 0.08 Group Sal, showed P3 to significantly differ from P1 (P = .048) and Sal (P = .007) groups. Regardless of the prednisone dose, all groups displayed impaired MT compared with the Sal group: P1 (P = .02); P2 (P = .02) P3 (P = .03). There was no interaction between the therapy and the treatment time for CBF (P = .10), MCTV (P = .71), and MT (P = .64). Prednisone reduced the transportability of mucus even when administered at low doses; however, this change was not sufficient to alter the mucociliary clearance. Only high doses of prednisone impaired mucociliary clearance.

Histochemical demonstration of sialic acids and antimicrobial substances in the porcine anal glands

The distribution of sialic acids and antimicrobial products (lysozyme, β-defensin-1, lactoferrin, IgA) in the anal glands of miniature pig was studied by glycoconjugate histochemistry and immunohistochemistry. The glandular acini of these glands exhibited considerable amounts of sialoglycoconjugates that terminated in Siaα2-6Gal/GalNAc or Siaα2-3Gal1-4GlcNAc, including O-acetylated sialic acids. Additionally, all antimicrobial products examined could be demonstrated in the anal glands, especially in the serous cells. The results obtained are discussed with regard to the functional significance of the anal glands. Our observations corroborated the view that sialic acids closely interact with defense cells and antimicrobial substances in the innate immune response. Therefore, the anal glandular secretions may function as protective agents in order to preserve the integrity of the anal region.

Histochemical analyses of anti-microbial substances in canine perianal skin with special reference to glandular structures

Circumanal glands are prominent features of the canine perianal skin, which are often located near to the sebaceous glands and apocrine glands. As the functional relevance of circumanal glands is yet unknown, we studied the localisation of sialic acids and anti-microbial substances (lysozyme, immunoglobulin A, lactoferrin, β-defensin) in these glandular structures by lectin histochemistry and immunohistochemistry. The glands exhibited a number of sialic acids that were linked to α2-6Gal/GalNAc and α2-3Galβ1-4GlcNAc. Additionally, lysozyme, lactoferrin and β-defensin could be demonstrated in the three types of skin glands, whereas IgA was only detectable in the apocrine glands. The results of the study suggest the specific significance of the circumanal glands. Independent of a certain endocrine role, their products may mainly function as protective agents to preserve the integrity of the anal region, considering that sialic acids and anti-microbial substances are important in defence mechanisms.

The effects on mucociliary clearance of prednisone associated with bronchial section

OBJECTIVE

Infections have been and remain the major cause of morbidity and mortality after lung transplantation. Because mucociliary clearance plays an important role in human defense mechanisms, the influence of drugs on the mucociliary epithelium of patients undergoing lung transplantation must be examined. Prednisone is the most important corticosteroid used after lung transplantation. The aim of this study was to evaluate the effects of bronchial transection and prednisone therapy on mucociliary clearance.

METHODS

A total of 120 rats were assigned to 4 groups according to surgical procedure or drug therapy: prednisone therapy (1.25 mg/kg/day); bronchial section and anastomosis + prednisone therapy (1.25 mg/kg/day); bronchial section + saline solution (2 ml/day); and saline solution (2 ml/day). After 7, 15, or 30 days, the animals were sacrificed, and the lungs were removed from the thoracic cavity. The in situ mucociliary transport velocity, ciliary beat frequency and in vitro mucus transportability were evaluated.

RESULTS

Animals undergoing bronchial section surgery and anastomosis had a significant decrease in the ciliary beat frequency and mucociliary transport velocity 7 and 15 days after surgery (p<0.001). These parameters were normalized 30 days after the surgical procedure. Prednisone improved mucous transportability in the animals undergoing bronchial section and anastomosis at 15 and 30 days (p<0.05).

CONCLUSION

Bronchial section and anastomosis decrease mucociliary clearance in the early postoperative period. Prednisone therapy improves mucus transportability in animals undergoing bronchial section and anastomosis.

Hypertonic saline solutions do not influence the solubility of sputum from secretor and non-secretor cystic fibrosis patients

INTRODUCTION

Functional alterations of the cystic fibrosis transmembrane conductance regulator gene (CFTR) increase the viscoelasticity of pulmonary secretions of cystic fibrosis (CF) patients and require the use of therapeutic aerosols. The biochemical properties of exocrine secretions are influenced by the expression of the FUT2 gene which determine the secretor and non-secretor phenotypes of the ABH glycoconjugates. The aim of this study was to determine the influence of secretor and non-secretor phenotypes by means of photoacoustic analysis, both the typical interaction time (t(0)) and the solubilization interval (Δt) of the sputum of secretor and non-secretor CF patients nebulized by hypertonic saline solutions at different concentrations.

MATERIAL AND METHODS

Sputum samples were obtained by spontaneous expectoration from 6 secretor and 4 non-secretor patients with CF. Each sample was nebulized with 3%, 6%, and 7% hypertonic saline solutions in a photoacoustic cell. The values of t(0) and Δt were determined using the Origin 7.5(®) computer program (Microcal Software Inc.). The t-test was employed using the GraphPad Instat 3.0(®) computer program to calculate the mean and standard deviation for each parameter.

RESULTS

For all hypertonic saline solutions tested, the mean values of t(0) and Δt do not show statistically significant differences between secretor and non-secretor patients.

CONCLUSIONS

The secretor and non-secretor phenotypes do not influence the in vitro solubilization of the sputum nebulized by hypertonic saline solutions at different concentrations when analysed by photoacoustic technique.

Rheologic properties of sinonasal mucus in patients with chronic sinusitis

BACKGROUND

Mucociliary clearance is impaired in chronic rhinosinusitis (CRS). Clearance of sinonasal secretions is influenced by its rheological properties. The purpose of this study was to describe the rheological properties of sinonasal mucus in patients with CRS and correlate them with disease severity.

METHODS

Twenty-three adult subjects with CRS underwent collection of sinonasal secretions. Samples were analyzed using the AR2000 cone and plate rheometer (TA Instruments, New Castle, DE) to determine the dynamic viscosity and elasticity. These properties were used to calculate mucus clearance indices. All patients completed the Sinonasal Outcome Test (SNOT-20). Recent sinus computed tomography (CT) scans were electronically reviewed and scored according to the Lund-McKay staging system.

RESULTS

The mean dynamic elasticity and viscosity of sinus mucus at 1 Hz were 78.24 +/- 103.4 Pa and 22.09 +/- 29.62 Pa, respectively. The mean elasticity and viscosity values at 10 Hz were 118.9 +/- 155.5 Pa and 32.36 +/- 45.58 Pa, respectively. Three indices of disease severity (SNOT-20 score, Lund-McKay score, and nasal polyps) correlated with increased mucus viscoelasticity and/or worsened mucociliary clearance indices (MCIs).

CONCLUSION

This study establishes the range of rheological properties of sinonasal mucus in patients with CRS and suggests an association between disease severity and MCIs.

Epithelium, cilia, and mucus: their importance in chronic rhinosinusitis

Chronic rhinosinusitis is a common disease resulting from inflammation of the sinonasal mucosa. It has long been recognized that patients with chronic rhinosinusitis have impaired capacity to clear sinonasal secretions. However, the cause of this pathologic process is not well understood. In this article the components of mucociliary clearance, including cilia, mucus production, and cilia beat frequency, are reviewed and alterations of the system discussed regarding contribution to the disease process.

Micro- and macrorheology of mucus

Mucus is a complex biological material that lubricates and protects the human lungs, gastrointestinal (GI) tract, vagina, eyes, and other moist mucosal surfaces. Mucus serves as a physical barrier against foreign particles, including toxins, pathogens, and environmental ultrafine particles, while allowing rapid passage of selected gases, ions, nutrients, and many proteins. Its selective barrier properties are precisely regulated at the biochemical level across vastly different length scales. At the macroscale, mucus behaves as a non-Newtonian gel, distinguished from classical solids and liquids by its response to shear rate and shear stress, while, at the nanoscale, it behaves as a low viscosity fluid. Advances in the rheological characterization of mucus from the macroscopic to nanoscopic levels have contributed critical understanding to mucus physiology, disease pathology, and the development of drug delivery systems designed for use at mucosal surfaces. This article reviews the biochemistry that governs mucus rheology, the macro- and microrheology of human and laboratory animal mucus, rheological techniques applied to mucus, and the importance of an improved understanding of the physical properties of mucus to advancing the field of drug and gene delivery.

Glycoconjugate expression of sinus mucosa in chronic rhinosinusitis: a lectin histochemical study

BACKGROUND

Glycoproteins are responsible for the rheological properties of the mucus. Changes in mucus viscosity may interfere with mucociliary clearance, leading to stasis and aggravation of chronic rhinosinusitis (CRS). The purpose of this study was to assess the composition and concentration of various sinus mucosa glycoproteins in normal and chronically inflamed sinuses.

METHODS

A semiquantitative scoring system was used to express the binding intensity of 10 lectins to 6 carbohydrates (galactose, sialic acid, N-acetylglucosamine, N-acetylgalactosamine [GalNac] [corrected], fucose, mannose) residing in the sinus mucosa of patients with CRS (N = 20) and normal controls (N = 10).

RESULTS

The mean CT score, compatible with extensive sinus disease, was 13.9 +/- 6.7. All six carbohydrates were found in the epithelium and submucosal glands of patients and controls. Peanut agglutinin staining showed significantly higher concentration of disaccharide galactose beta 1,3 GalNac [corrected] in epithelial goblet cells and in submucosal mucous and mixed glands of patients compared with that of controls (p = 0.01, p = 0.03, and p = 0.018, respectively). The epithelial glycocalyx of patients was also significantly more abundant in fucose and in GalNac [corrected] (p = 0.015, and p < 0.001, respectively).

CONCLUSION

Glycoconjugate expression of the sinus mucosa in CRS is markedly altered in extensive inflammatory conditions. The increased concentration of galactose beta 1,3 GalNac [corrected] in CRS probably contributes to the high viscosity of the nasal mucus and interferes with normal mucociliary clearance. Exposed peripheral galactose residues may serve as attachment receptor sites for pathogenic bacteria. Means interfering with the ability of bacteria to adhere to specific receptors on host tissues warrant additional research.

Methods for studying mucociliary transport

Mucociliary transport dysfunctions can impair the quality of life of patients suffering from chronic rhinossinusitis and lead to severe consequences such as alterations in respiratory physiology or even death as in cases of cystic fibrosis and primary ciliary dyskinesia. Therefore, it is crucial to understand the physiology of the mucociliary apparatus and how its components (cilia, mucus-periciliary layer and its interaction) affect the clearance of respiratory secretions. Aims: This paper aims to review and to discuss different techniques for studying mucociliary transport and their clinical and experimental applicability. Conclusions: The methods listed in this revision provide us with valuable information about different aspects of the mucociliary transport. Some of the methods listed are more suitable for clinical practice and present reproducible results. Others, show only applicability in experimental settings due to technical difficulties or financial limitations. However, it is important to emphasize that up to now there is no method that can evaluate ciliary beating frequency (CBF) in vivo and in situ. Such a method would become a valuable tool in the scientific scenario and in the clinical practice, supporting the diagnosis of ciliary dyskinesias and avoiding the use of invasive procedures to corroborate the clinical suspicion

Métodos de estudo do transporte mucociliar

Disfunções no transporte mucociliar trazem desde queda na qualidade de vida dos pacientes, como nas rinites e rinossinusites crônicas, até graves conseqüências com risco de seqüelas irreversíveis e mesmo letais, como nos casos de fibrose cística e das discinesias ciliares primárias. Desta forma, torna-se fundamental o conhecimento do funcionamento normal do aparelho mucociliar e de como alterações em seus componentes (cílio, muco-fluido periciliar e interação dinâmica entre ambos) afetam o transporte das secreções respiratórias. OBJETIVOS: Este artigo visa a revisar e discutir as diferentes técnicas de avaliação do transporte mucociliar descrevendo suas peculiaridades e aplicabilidades clínicas e experimentais. CONCLUSÕES: Os métodos citados nesta revisão nos fornecem informações importantes sobre os diferentes aspectos do transporte mucociliar. Alguns apresentam uma maior facilidade de realização e resultados reprodutíveis, já outros apenas mostraram-se com aplicabilidade em protocolos de pesquisa em virtude de dificuldades técnicas e limitações financeiras. Há que se considerar a inexistência de métodos que avaliem ambulatorialmente a freqüência de batimento ciliar (FBC) "in vivo" e "in situ", o que se tornaria uma ferramenta importante, tanto no âmbito científico, quanto na prática clínica, auxiliando no diagnóstico das discinesias ciliares e evitando a realização de procedimentos mais invasivos para a sua confirmação diagnóstica.

Sulphurous-arsenical-ferruginous (thermal) water inhalations reduce nasal respiratory resistance and improve mucociliary clearance in patients with chronic sinonasal disease: preliminary outcomes

CONCLUSIONS

In order to confirm these preliminary results, a prospective double-blind study has been instituted in Padova University ENT Section to compare the efficacy of sulphurous-arsenical-ferruginous thermal water nasal irrigations vs isotonic sodium chloride solution nasal irrigations after functional endoscopic sinus surgery for chronic sinusitis.

OBJECTIVES

Despite their widespread use, much uncertainty exists about the indications and therapeutic mechanisms of nasal thermal water inhalations in the treatment of sinonasal chronic disease. The aim of the present study was to evaluate the effects of sulphurous-arsenical-ferruginous thermal water inhalations on nasal respiratory flow, mucociliary transport, nasal cytology, and chemo-physics of nasal mucus in a group of consecutive patients with chronic sinonasal disease.

PATIENTS AND METHODS

Thirty-seven patients with chronic sinonasal disease underwent a 12-day course of sulphurous-arsenical-ferruginous thermal water warm vapour inhalations (38 degrees C) followed by nasal aerosol of the same thermal water (7 microns micelle).

RESULTS

This preliminary study showed that a course of sulphurous-arsenical-ferruginous thermal water inhalations determined a significant improvement in nasal flow and reduction of nasal resistance; a statistically significant reduction of mean mucociliary transport time, from pathologic to physiologic values, has also been shown. Statistical analysis of our data confirmed that the presence of nasal bacteria was significantly reduced by thermal water inhalations.

Mucociliary clearance – a critical upper airway host defense mechanism and methods of assessment

PURPOSE OF REVIEW

Mucociliary clearance is a critical host defense mechanism of the airways. Effective mucociliary clearance requires appropriate mucus production and coordinated ciliary activity. The important role of these two components is best demonstrated in disorders such as primary ciliary dyskinesia and cystic fibrosis, both of which lead to lifelong recurrent respiratory tract infections. We review the methods used to analyze mucociliary clearance.

RECENT FINDINGS

Utilization of microdialysis probes has improved temporal resolution of mucociliary clearance in murine airways, availing many genetic mouse models to critical mucociliary clearance analysis, while improved fixation technique for transmission electron microscopy has allowed for detailed resolution of the airway surface liquid. High-speed digital video analysis has improved quantification of ciliary beat frequency while advancements in air-liquid interface culturing techniques have generated in-vitro models to investigate mucociliary clearance.

SUMMARY

Advancements in techniques for analysis of mucociliary clearance have improved our understanding of the interaction between the respiratory epithelium and the airway surface liquid, resulting in the ability to study pathologic processes involving mucociliary clearance in great detail.

Photoacoustic monitoring of the absorption of isotonic saline solution by human mucus

Viscosity and elasticity are the fundamental rheologic properties of respiratory mucus, and are important determinants of transportability of mucus in the mucociliary system. One technique that permits to monitor indirectly the rheologic properties of any sample is the photoacoustic technique. Using that technique, the absorption of isotonic saline solution by human mucus was monitored. The mucus was obtained from 11 volunteers, divided into two groups: five volunteers presenting pneumology symptoms (group I) and six healthy volunteers (group II). The photoacoustic signal of the mucus absorbing the saline solution was monitored as function of time, with measurements being performed each 10 min, up to 120 min. The resulting curves were fitted to sigmoidal curves to simulate the evolution on time of the photoacoustic signal. A characteristic time for the half saturation of the absorption process was obtained. For group I the time obtained was 23.3+/-5.3 min and for group II the time obtained was 55.0+/-7.7 min, both means being significantly different (Student t-test, p<0.05). This result supports the empirical practice of treating individuals presenting symptoms of airway obstruction with about 30 min of inhalations of isotonic saline solution vapor for the clearance of the airways.

Altered sinonasal ciliary dynamics in chronic rhinosinusitis

BACKGROUND

Although multiple etiologies contribute to the development of rhinosinusitis, a common pathophysiological sequelae is ineffective sinonasal mucociliary clearance, resulting in stasis of sinonasal secretions, with subsequent infection, and persistent inflammation. The respiratory cilia beat continually at a basal rate, while during times of stress, such as exercise or infection, ciliary beat frequency (CBF) increases, accelerating mucus clearance. Previous investigations have led to conflicting results with some authors reporting decreased CBF while others have found normal values of CBF in patients with chronic rhinosinusitis (CRS). Additionally, these studies have only analyzed basal CBF. The goal of this study was to compare the basal as well as the stimulated sinonasal CBF in patients with CRS versus controls.

METHODS

A dual temperature controlled perfusion chamber, differential interference contrast microscopy, and high-speed digital video were used to analyze both basal and adenosine triphosphate (100 microM)-stimulated CBF in human sinonasal mucosal explants.

RESULTS

Although no difference in basal CBF was detected between control and CRS patients, a marked difference in stimulated CBF was noted. Exogenously applied adenosine triphosphate resulted in a 50-70% increase of CBF in control tissue with a minimally observed CBF increase in explants from CRS patients.

CONCLUSION

Dynamic regulation of respiratory ciliary activity is critical for the respiratory epithelium to adapt to varying environmental situations. Thus, diminished or absent adaptation could predispose the sinonasal cavity to accumulation of inhaled infectious and noxious particulate matter resulting in infection/inflammation. Our findings suggest that CRS patients have decreased sinonasal ciliary adaptation to environmental stimuli.

Local administration of 2% trimecaine affects the content of fucosylated glycoconjugates in goblet cells in rabbit tracheal epithelium

The proportion of fucosylated glycoconjugate-containing rabbit tracheal goblet cells after intratracheal application of trimecaine was studied to evaluate its possible unfavourable effects. This lapine model is comparable with diagnostic findings in humans because airway epithelia in humans and rabbits are similar; tracheal epithelium is also practically identical to bronchial epithelium in both species. Local trimecaine anaesthesia caused a proportional decrease in percentage of the tracheal goblet cells containing both alpha(1-2)- and alpha(1-6)-, alpha(1-3)- and alpha(1-4)-fucosylated glycoconjugates as revealed 10 min postexposure using lectin histochemistry. In previous studies, only mild ultrastructural damage to the airway's epithelium was revealed, but a conspicuous decrease in sialylated glycoconjugate-containing tracheal goblet cells and the dominance of acidic sulphated glycoconjugates were observed as after-effects of the same treatment. Glycoconjugate changes can influence the inner environment of airways (e.g. viscoelastic properties of the airways' mucus and mucosal barrier functions) and thus the patient's defence barriers in airways may be weakened. Concurrently, the histochemical properties of goblet cells can be altered in bronchoscopic specimens. Since trimecaine is widely used as local anaesthesia in airways in bronchoscopy, it is necessary to heed these aforementioned effects.

Parameters affecting the drug release from in situ gelling nasal inserts

The purpose of the study was to investigate the influence of physicochemical drug properties, drug loading, and composition of the release medium on the drug release from in situ gelling nasal inserts. Sponge-like nasal inserts of carrageenan and HPMC K15M with the model drugs oxymetazoline HCl, diprophyllin, and acetaminophen (APAP) were prepared by lyophilization. Drug release studies at different drug loadings were performed in various release media. Raman analysis, DSC, and SEM were conducted to analyze the physical state of the drugs in the inserts. All drugs were dissolved in the solid HPMC inserts and were released at similar rates at all investigated loadings except for the least soluble APAP. APAP concentrations in the hydrating HPMC K15M inserts in excess of its solubility limit resulted in reduced relative release rates at higher drug loadings. Drug-polymer interactions (formation of less soluble drug-polymer salts) resulted in a slower release of oxymetazoline HCl from carrageenan inserts than from HPMC K15M inserts. Changes in the composition of the release medium affected the water uptake of carrageenan but not of HPMC K15M inserts. Oxymetazoline release from carrageenan inserts increased with higher Na+-content of the medium because of ion exchange and at low (pH 2) as well as at high pH (pH 10). The osmolality of the release medium had no effect. The solubility of the drug, its physical state in the polymer matrix, and drug-polymer interactions governed the drug release from nasal inserts. The release from inserts prepared with oppositely charged polymers and drugs was influenced by electrostatic drug-polymer interactions and by the composition of the release medium.

Cytochemical characterization of glycoconjugates in the apocrine glands of the equine scrotal skin

Cytochemistry of glycoconjugates in the apocrine glands in the scrotal skin of the horse was studied using cytochemical methods for electron microscopy, particularly lectin cytochemistry. The secretory cells possessed a variable number of secretory vesicles, a well-developed Golgi apparatus, and abundant cisternae of the rough endoplasmic reticulum. Additionally, the basolateral plasma membrane formed numerous interdigitating folds. Glycoconjugates with vicinal diol groupings were present predominantly in the secretory vesicles, the Golgi apparatus, the surface coat of the plasma membrane, and the majority of the intracellular membranes. With lectin cytochemistry, the secretory vesicles of the glandular cells exhibited glycoproteins with different terminal sugars (alpha-D-mannose, beta-D-galactose beta-N-acetyl-D-glucosamine, and sialic acid). Several sugars were distinctly prominent in the surface coat of the plasma membrane of the secretory cells. The cytochemical properties of the complex glycoconjugates found are discussed in relation to the specific functions of the glandular secretions. These glands may have an important role in not only thermoregulation but protection of the scrotal skin, a specific body region.

Expression and distribution of ion transport mRNAs in human nasal mucosa and nasal polyps

CONCLUSIONS

Our results indicate that the electrogenic kidney Na(+)/HCO(3)(-) cotransporter (kNBC), KCl cotransporter (KCC1 and -4) and Ca(2+)-activated Cl(-) channel (CaCC1, -2, -3) mRNAs are expressed in normal nasal mucosa and nasal polyp, suggesting that altered expression of all CaCC mRNAs in nasal polyp may cause impaired electrolyte and water transport across the epithelial cells.

OBJECTIVE

Electrolyte transport by nasal epithelia has been suggested to be important for controlling the quantity and composition of the nasal fluid and may play an important role in the development of nasal polyps. Transepithelial transport of ions and water in various fluid-transporting epithelia is strictly dependent on the localization of specific membrane proteins in the polarized epithelial cells. In this study we investigated the expression and distribution of mRNA transcripts for kNBC, pancreatic NBC, KCC1, -2, -3, -4 and CaCC1, -2, -3 gene families in human nasal mucosa and nasal polyp.

MATERIAL AND METHODS

The expression and localization of these gene families were investigated in inferior turbinate tissues and nasal polyp using reverse transcriptase polymerase chain reaction (RT-PCR), semiquantitative RT-PCR and in situ hybridization.

RESULTS

mRNAs for kNBC, KCC1 and -4 and all the CaCC families (CaCC1, -2 and -3) are expressed in human turbinate mucosa and nasal polyp. The expression levels of kNBC and KCC1 and -4 mRNAs did not differ between nasal mucosa and nasal polyp. However, the expression levels of all the CaCC genes were significantly decreased in nasal polyp. In situ hybridization revealed that the expression of these genes was mainly localized in the epithelial layer and submucosal glands of inferior turbinate mucosa and in the epithelial layer of nasal polyp.

Morphology and glycoconjugate histochemistry of the eccrine glands in the snout skin of the North American raccoon (Procyon lotor)

The eccrine nasolabial glands were found in the hypodermis of the nasal plane in the North American raccoon (Procyon lotor). In addition to light and electron microscopic observations, the distribution and selectivity of complex glycoconjugates in the eccrine tubular glands of the raccoon snout skin were studied using various histochemical methods, particularly lectin staining. The secretory epithelium and the luminal secretions exhibited high amounts of glycoconjugates with various saccharide residues (alpha-D: -mannose, alpha-L: -fucose, beta-D: -galactose, beta-N-acetyl-D: -glucosamine, sialic acid). The excretory duct cells also showed positive reactions with most of the histochemical methods applied. The results are discussed with regard to possible functions of the glandular secretions. The complex glycoconjugates that are produced by the eccrine nasolabial glands may be related to moistening of the skin surface as well as protecting the epidermis against physical damage or microbial contamination. This is the first report on the glands in the snout skin of carnivores.

Ultracytochemical Demonstration of Glycoproteins in the Eccrine Glands of the Digital Pads of the North American Raccoon (Procyon lotor)

In the eccrine glands of the digital pads of the North American raccoon (Procyon lotor), ultrastructural localization of glycoproteins with various saccharide residues was studied using preferably lectin cytochemical methods. Secretory granules observed in the dark cells exhibited glycoproteins with different terminal sugars (alpha-D-mannose, beta-D-galactose, beta-N-acetyl-D-glucosamine and sialic acid). The cytoplasm of the clear cells contained numerous glycogen particles. Several sugars were also detectable in the surface coat of the plasma membrane of the secretory cells. The results obtained could be helpful in understanding secretion production and cell related secretion functions of the eccrine glands of the raccoon digital foot pads.

Bacterial products increase expression of the human cathelicidin hCAP-18/LL-37 in cultured human sinus epithelial cells

The respiratory epithelium plays a major role in the primary defense of the airways against infection. It has been demonstrated that bacterial products are involved in the induction of inflammatory reactions of the upper airways. Little is known about the effects of bacterial products on expression of the antimicrobial peptide hCAP-18/LL-37, the only human cathelicidin identified so far. The aim of this study was to investigate the effects of bacterial products from both gram-positive and gram-negative bacteria on the expression of hCAP-18/LL-37 by sinus epithelial cells using an air-exposed tissue culture model. Lipopolysaccharide and lipoteichoic acid both increased hCAP-18/LL-37 expression in cultured sinus epithelium as assessed by immunohistochemistry, where maximal stimulation occurred at 100 ng ml(-1) lipopolysaccharide or 10 microg ml(-1) lipoteichoic acid. The stimulatory effect of lipopolysaccharide and lipoteichoic acid was not restricted to expression of hCAP-18/LL-37, since also mucin expression and IL-8 release from cultured sinus epithelium cells were increased by lipopolysaccharide and lipoteichoic acid. This suggests that bacterial products may stimulate innate immunity in the upper airways.