Rationale for targeting pepsin in the treatment of reflux disease.

OBJECTIVES: We undertook to (1) obtain unequivocal evidence to confirm or rebut our initial observations that pepsin is taken up by hypopharyngeal epithelial cells by receptor-mediated endocytosis, (2) investigate whether uptake of pepsin at pH 7, in nonacidic refluxate, is of pathological significance, and 3) test our hypothesis that inactive but stable pepsin (

Unique presentation of cricoid cartilage fracture causing intermittent dyspnea without preceding trauma.

Cricoid cartilage fracture is generally caused by significant neck trauma and causes continuous dyspnea, neck pain, or hoarseness developing immediately after the traumatic episode. A 69-year-old woman without any history of trauma was admitted to our hospital with intermittent dyspnea. Six months before admission she had started to complain of dyspnea occurring several times a month without warning, improving spontaneously within a few hours without treatment. Her primary care doctor diagnosed asthma and she was treated with inhaled short-acting beta agonists and glucocorticoids, without improvement. On initial evaluation at our hospital, the cause of dyspnea was unclear. Laryngoscopy was performed, which excluded vocal cord dysfunction. A further attack of dyspnea occurred on the fourth admission day. Stridor was evident during the attack, and bronchoscopy revealed subglottic narrowing of the trachea on both inspiration and expiration with no mass or foreign objects. Computed tomography (CT) of the neck revealed cricoid cartilage fracture causing airway narrowing and dyspnea. She was orally intubated, and tracheostomy was performed 2 weeks later to maintain her airway, which resolved her dyspnea. This patient's presentation was unique in two aspects. First, there was no history of trauma that may cause her cricoid cartilage fracture. Second, her symptoms of dyspnea were intermittent rather than continuous. These aspects led to suspicions of other diseases such as asthma or vocal cord dysfunction, thus delaying the diagnosis. Cricoid cartilage fracture should be considered in patients with dyspnea of unknown cause, irrespective of continuous or intermittent symptoms and preceding traumatic episodes.

Matrix metalloproteinases 2 and 9 are concentrated in the luminal aspect of the cricoid cartilage, diminish with loss of perichondrium, and are reinstated by transforming growth factor beta 3.

OBJECTIVES: We determined the location of matrix metalloproteinases (MMP) 2 and 9, and whether the luminal perichondrium or transforming growth factor (TGF) beta3 influences the presence of MMP-2 and/or -9 within the chondrocytes of the cricoid cartilage. METHODS: Subglottises from 15 neonatal mice were divided into group A (N = 5; luminal epithelium intact, grown in basic medium), group B (N = 5; epithelium-free, with sections of luminal perichondrium removed, grown in basic medium), and group C (N = 5; epithelium-free, with sections of luminal perichondrium removed, grown in basic medium with supplemental TGF-beta3). Immunohistochemical analysis was done to identify MMP-2 and -9 distributions. RESULTS: Group A demonstrated concentrations of MMP-2 and -9 in the luminal perichondrial and adjacent chondrocytes with a gradual decrease in signal intensity toward the outer perichondrium. Group B showed findings similar to those in group A, but in the region of removed perichondrium, the adjacent chondrocytes lost MMP-2 and -9 signal. The group C rings demonstrated reestablishment of MMP-2 and -9 signal in regions of luminal perichondrial loss. CONCLUSIONS: Localization of MMP-2 and -9 is predominantly in the luminal perichondrium and gradually decreases toward the outer perichondrium. The luminal perichondrium maintains expression of MMP-2 and -9 within the adjacent chondrocytes. Exogenous TGF-beta3 reestablishes production of at least MMP-9, and probably MMP-2, in cricoid cartilages missing luminal perichondrium.

Patterns of cartilage structural protein loss in human tracheal stenosis.

OBJECTIVES: The study sought to identify which of the major structural proteins in tracheal cartilage are lost in the inflammatory process, and to determine whether damaged cartilage shows signs of regeneration and whether this is an age-dependent phenomenon. STUDY DESIGN: Immunohistochemical analysis. METHODS: Archival human tracheal and subglottic stenosis segments removed for the treatment of airway compromise were investigated by means of immunohistochemical analysis for differential loss of collagen type I or type II or aggrecan. RESULTS: Specimens were found to have preferentially lost collagen I and aggrecan in areas of severe disruption of the cartilage ring. Collagen II was preserved. In addition, areas of apparent cartilage regeneration were identified based on increased collagen II and aggrecan relative to baseline levels in uninjured sections of the rings. Regenerative capacity was present in most of the specimens investigated and was not age specific. CONCLUSIONS: Collagen I and aggrecan are lost in areas of severe ring compromise, indicating that at least one of these two molecules is responsible for structural integrity. The remaining cartilage has some regenerative capacity, but it is small relative to the degree of cartilage damage. No new collagen I was identified in the cartilage ring, indicating that, although an intense inflammatory reaction occurred, fibroblasts did not deposit new collagen I as seen in other scar tissues.

In vitro regulation of expression of cartilage-derived morphogenetic proteins by growth hormone and insulinlike growth factor 1 in the bovine cricoid chondrocyte.

OBJECTIVES: To delineate the endogenous growth factors that regulate cricoid cartilage growth at the molecular level. Specifically, to attempt to establish the presence of cartilage-derived morphogenetic proteins (CDMPs), cartilage-specific members of the bone morphogenetic protein family, in newborn bovine cricoid chondrocytes and to assess the expression of these endogenous growth factors with the addition of exogenous growth hormone or insulinlike growth factor 1 in an in vitro chondrocyte culture model. METHODS AND DESIGN: Basic science molecular biologic research methods, including high-density monolayer and explant chondrocyte cultures with extraction of messenger RNA and quantitation via Northern blot hybridization via radiolabeled complementary DNA probes. SETTING: Intramural basic science research laboratory. RESULTS: Both CDMP-1 and CDMP-2 were found in newborn cricoid chondrocytes. Addition of exogenous growth hormone did not appear to influence the expression of CDMP-1 or CDMP-2. Addition of exogenous insulinlike growth factor 1 appeared to down-regulate the expression of CDMP-1 but had no effect on the expression of CDMP-2. No major differences in CDMP level of expression were noted between high-density monolayer cultures vs explant cultures. No tissue specificity differences were noted in regulation of CDMPs between cricoid and articular chondrocytes. CONCLUSIONS: Our preliminary studies indicate the presence of endogenous morphogenetic proteins in newborn bovine cricoid chondrocytes. These novel polypeptide hormones (CDMP-1 and CDMP-2) have not been previously reported in laryngeal cartilage chondrocytes. Change in level of transcription of these morphogenetic proteins under various in vitro conditions suggests that these proteins are subject to regulation and/or play a regulatory role in cricoid chondrocyte growth and differentiation. Further experimentation is needed to confirm these findings.

Growth and development of the human cricoid cartilage: an immunohistochemical analysis of the maturation sequence of the chondrocytes and surrounding cartilage matrix.

OBJECTIVES: The goal was to determine maturational changes in the human cricoid cartilage. STUDY DESIGN: The study involved immunohistochemical staining of collagen II (a marker of proliferating chondrocytes), matrilin-1 (a marker of post-proliferative chondrocytes), and collagen X (a marker of hypertrophic chondrocytes). Specimens included uninjured human cricoid cartilages at 18 and 41 weeks' gestation and 1, 4, and 13 years postpartum. RESULTS: This study demonstrated that type II collagen peaks in concentration at approximately 41 weeks' gestation. Matrilin-1 is present in progressively lower concentration in the central core of the cricoid ring, but the peripheries of the ring contain the protein in relatively high concentration. Type X collagen is not expressed in the age groups tested. CONCLUSIONS: These biochemical markers lend further support to a chondrocyte proliferative phase that slows between 1 and 4 years of age. Chondrocytes then enter a phase histologically similar to the hypertrophic phase but are biochemically different than hypertrophic chondrocytes destined for endochondral ossification.

Role of laryngoscopy, dual pH probe monitoring, and laryngeal mucosal biopsy in the diagnosis of pharyngoesophageal reflux.

There is no standard for determining significant pharyngoesophageal reflux. This prospective blind comparison study compared dual pH probe studies, direct laryngoscopy, and mucosal biopsy in children without symptoms of gastroesophageal reflux who underwent airway evaluation. Significant reflux to the lower esophageal probe did not correlate with statistical significance with reflux to the upper probe. In this group of asymptomatic patients, a positive lower pH probe finding did not correlate with upper or lower esophageal mucosal inflammation. Eosinophilia in the esophageal mucosa is diagnostic of gastroesophageal reflux disease, and was seen in 5 of the laryngeal biopsies. A weak correlation was seen between positive findings at laryngoscopy and positive posterior cricoid biopsy in this group. There may be no consistent way to predict significant pharyngoesophageal reflux in asymptomatic patients. Single-probe pH testing will not predict significant pharyngoesophageal reflux with mucosal changes. Laryngoscopy and upper pH probe findings only weakly correlate with significant histologic findings. Laryngeal and posterior cricoid biopsy may be the only sensitive test for mucosal injury. Clinical trials of empiric antireflux therapy should be used to determine whether the laryngeal changes seen in these patients are reversible.

An evaluation of knowledge and skill on cricoid pressure among emergency personnel.

BACKGROUND: Cricoid pressure (CP) is a step during rapid sequence induction. Previous studies showed a poor clinical application of CP despite a reasonable theoretical knowledge of CP. This study aims to evaluate the proficiency and knowledge retention on CP among the emergency staff in the Emergency Department, Universiti Kebangsaan Malaysia Medical Centre. MATERIALS AND METHODS: This is questionnaire-based observational comparative study. Once the questionnaire is filled, the application of CP is tested on an airway model and competency level is documented. An education hand out is passed to all participants after the procedure. The improvement and knowledge retention were assess after 2 month. RESULTS: A total of 81 completed surveys were returned comprises of of 34 medical officers, 23 staff nurses and 24 assistant medical officers. 75.3% subjects have work experience more than a year but only 59.3% of them were trained in CP application. A total of 69.1% participants passed the pre educational handout test and 100% passed the post educational handout test. However, for pre educational handout phase, 81.5% participants passed the theory part while only 42% passed the practical component. In post educational handout phase, the number of respondents who passed both components was 97.5% and 63% respectively. There are positive correlation between designation and working experience with overall passes in this study. CONCLUSIONS: The theoretical knowledge of CP is satisfactory but clinical application is poor especially in the pre educational handout phase. The educational handout is proved to improve the knowledge transfer and retention with regards to CP.

Composition of the extracellular matrix in human cricoarytenoid joint articular cartilage.

The extracellular matrix of the human cricoarytenoid joint articular cartilage is involved in different pathological changes. Interestingly, in contrast to the limb joints, the extracellular matrix composition of the healthy cricoarytenoid joint articular cartilage has not yet been elucidated except by some light microscopical investigations. The present study investigates the extracellular matrix components of the cricoarytenoid joint articular cartilage by means of light microscopy, immunohistochemistry, transmission electron microscopy and scanning electron microscopy and compares them with the limb joints for a better understanding of their involvement in joint disease. Chondrocytes near the joint surface of the cricoid and arytenoid cartilage differ from chondrocytes of deeper cartilage layers. The extracellular matrix of the articular cartilage contains chondroitin-4-sulfate, chondroitin-6-sulfate and keratansulfate as well as collagen types II, III, VI, IX and XI. Type-III-collagen shows a special distribution throughout the joint cartilage. In deeper cartilage layers, type-III-collagen occurs only pericellularly; in higher cartilage layers type-III-collagen is also located territorially and interterritorialy in small amounts. Scanning and transmission electron microscopy have revealed the articular surface of the cricoid and arytenoid cartilage to consist of a network of irregularly organized collagen fibrils, which are lined by a layer of electron dense material. The network coats subjacent collagen bundles which descend obliquely downward and intermingle at right angles in the middle part of the articular cartilage with collagen bundles of the deeper cartilage zones. The articular cartilage surface shows structural characteristics which differ from the underlying cartilage. The superficial electron dense layer possibly plays a role in the lubrication of the articular cartilage surface. The alignment of the fibrillar structures in the articular cartilage of the cricoarytenoid joint varies from those of the limb joints based on the different strain occurring during arytenoid movement. Nevertheless, the human cricoarytenoid joint articular cartilage can be compared with the joints of the limbs despite its extracellular matrix composition and its involvement in joint pathology. Evidence of type III collagen in the outermost layer of the articular cartilage of the cricoarytenoid joint presents a peculiarity, which has yet not be demonstrated in the articular cartilage of limb joints.

Osteoarthritis in cricoarytenoid joint.

OBJECTIVE: Occurrence of osteoarthritis is a frequent event of limb joints in people over 40 years of age. The human cricoarytenoid joint is comparable with the joints of the limbs despite its structure and extracellular matrix composition. To date, little is known about the occurrence of osteoarthritis in the human cricoarytenoid joint. METHODS: Sixty-eight cricoarytenoid joints (42 male and 26 female, age 25-98 years) were analysed by means of histology, lectin histochemistry, immunohistochemistry as well as scanning and transmission electron microscopy. RESULTS: About 50% of the investigated cricoarytenoid joints aged over 40 years show degenerative changes in their joint surface structure at varying levels of intensity. The articular cartilage surface is fibrillated in some places and sometimes shows fissures. A demascing of collagen fibrils next to the joint surface and a loss of proteoglycans in the upper cartilage layers can be observed. Chondrocytes near the joint surface appear as voluminous chondrocyte clusters. The clusters and the superficial cartilage layer show a positive reaction to type VI collagen antibodies. The distribution patterns of lectins are completely changed in fibrillated cartilage areas. CONCLUSION: Degenerative alterations in diarthrodial joints resembling osteoarthritis can occur in the joints of the larynx. These structural changes of the articular cartilage are comparable to osteoarthritis of the limb joints. Osteoarthritis in the cricoarytenoid joint may lead to impaired movements of the arytenoid cartilages. Functionally the structural changes may lead to negative consequences during vocal production, such as impaired vocal quality and reduced vocal intensity.