Biogeography of the Respiratory Tract Microbiome in Patients With Malignant Tracheal Tumors.

BACKGROUND: This study aimed to characterize the bacterial microbiota in the oral cavity (OC), throat, trachea, and distal alveoli of patients with primary malignant tracheal tumors (PMTT), including squamous cell carcinoma (SCC) and salivary gland carcinoma patients (SGC), for comparison with a matched non-malignant tracheal tumor (NMTT) group. METHODS: Patients with pathological diagnosis of PMTT and NMTT were included in this study. Saliva, throat swab (TS), trachea protected specimen brush (PSB), and bronchoalveolar lavage fluid (BALF) samples were collected for 16S rRNA gene sequencing. The composition, diversity, and distribution of the microbiota were compared among biogeographic sampling sites and patient groups. The relationship between the genera-level taxon abundance and tracheal tumor types was also investigated to screen for candidate biomarkers. FINDINGS: The most represented phyla in the four sites were Bacteroidetes, Firmicutes, Proteobacteria, and Fusobacteria. In SCC patients, the relative abundance of Bacteroidetes and Firmicutes gradually decreased with increasing depth into the respiratory tract, while the relative abundance of Proteobacteria gradually increased. Bacterial communities at the four biogeographic sites formed two distinct clusters, with OC and TS samples comprising one cluster and PSB and BALF samples comprising the other group. Principal coordinate analysis showed that trachea microbiota in SCC patients were distinct from that of SGC or NMTT patients. In the trachea, AUCs generated by Prevotella and Alloprevotella showed that the abundance of these genera could distinguish SCC patients from both NMTT and SGC patients. INTERPRETATION: The structure of respiratory tract microbiota in PMTT patients is related to tumor type. Certain bacteria could potentially serve as markers of SCC, although verification with large-sample studies is necessary.

Polydopamine-induced tooth remineralization.

Inspired by mussel bioadhesion in nature, dopamine is extensively used for biomaterial surface modification. In this study, we coated dopamine on demineralized enamel and dentin surfaces to evaluate the effect of polydopamine coating on dental remineralization. Dental slices containing enamel and dentin were first etched with 37% phosphoric acid for 2 min, followed by immersion in a 2 mg/mL freshly prepared solution of dopamine (10 mM Tris buffer, pH 8.5) for approximately 24 h at room temperature in the dark to obtain polydopamine coating. Then, the dental slices with and without polydopamine coating were immersed in the supersaturated solution of calcium and phosphate at 37 °C for 2 and 7 days. The supersaturated solution of calcium and phosphate was refreshed each day. The precipitates were characterized by SEM, XRD, FTIR, microhardness, and nanoscratch analyses. No significant difference was observed in the remineralization of enamel whether it was coated with polydopamine or not. However, a significant difference was found in dentin remineralization between dentin with and without polydopamine coating. Polydopamine coating remarkably promoted demineralized dentin remineralization, and all dentin tubules were occluded by densely packed hydroxyapatite crystals. Thus, coating polydopamine on dental tissue surface may be a simple universal technique to induce enamel and dentin remineralization simultaneously.

[Primary malignant airway neoplasms in 4 children].

OBJECTIVE: Primary airway neoplasms are extremely rare in the pediatric age group. This paper reports 4 children with primary airway neoplasms to explore the clinical manifestations, safety and efficacy of bronchoscopic interventions. METHOD: The data of pathology, photographic documentation and imaging studies were analyzed. RESULT: Of the 4 reported lesions, 2 were characterized by low-grade (2 with mucoepidermoid carcinoma) and 2 by high grade malignant (spindle cell carcinoma and malignant lymphoma). Onset of clinical manifestations occurred at the ages of 7 months to 7 years. All of them were initially misdiagnosed as bronchitis, asthma or atelectasis. The lesions located in trachea in 2 patients, in left bronchus of 1 patient and in right middle bronchus of 1 case. Atelectases occurred in bilateral bronchus where the lesions obstructed almost the entire lumen at the time of diagnosis. The diagnosis of airway masses depends upon maintaining a high index of suspicion, complemented by imaging and timely diagnostic endoscopy. The lesions were completely removed in 3/4 patients except 1 died during bronchoscopic procedures. CONCLUSION: The children with malignant airway neoplasms were presented with cough and wheezing without specific manifestations. Bronchoscopic interventions were effective in the treatment of non-operative cases. General anesthesia is strongly recommended for interventional bronchoscopy.

[Endoscopic retrieval of metallic stents in patients with airway diseases].

OBJECTIVE: To evaluate the indications, techniques, outcomes and complications of metallic stent removals in patients with airway disorders. METHODS: A retrospective analysis was performed in 43 patients with 47 tracheobronchial stents. The airway stent retrieval was performed under the guidance of rigid or flexible bronchoscopy between November 2005 and November 2009. There were 25 cases with 27 Z-type stents (25 covered metallic stents, CMS; 2 uncovered metallic stents, UCMS) and 18 cases with 20 Nitinol stents (4 CMS, 16 UCMS). Excessive stent-related granuloma formation or recurrent tumor in patients with UCMS group was similar to those with CMS (94.4% vs 89.7%). Fracture of stents in patients with UCMS group was higher than that in CMS group (83.3% vs 10.3%, P < 0.01). RESULTS: Thirty-eight of 47 (80.9%) stents (Z-type stents 85.2%, Nitinol 75.0%) were successfully removed. Among them, 15 stents (39.5%) were retrieved by rigid bronchoscopy and 23 (60.5%) stents by flexible bronchoscopy (20 under local anesthesia and 3 under pain-free anesthesia). 87.0% (20/23) Z-type CMS was removed with a retrieval hook by a flexible bronchoscopy under local anesthesia with an average duration of pre-removal stenting of (3.5 +/- 0.6) months while 80% (12/15) Nitinol UCMS removed by a rigid bronchoscopy under general anesthesia with an average duration of pre-removal stenting of (10.7 +/- 3.7) months. A successful retrieval of intact stents was achieved in 84.0% (21/25) of CMS while 92.3% (12/13) of UCMS had a retrieval of rupture stent or piecemeal. In all cases, major post-removal complications included profuse hemorrhage (n = 4) and mucosal tear (n = 15). No mortality occurred during the procedure. CONCLUSIONS: The indications for endoscopic retrieval of metallic stents include excessive or recurrent granuloma formation or tumor, recurrence of stenosis after stenting, stent fracture and conclusion of treatment, 3 - 4 months post-stenting in patients with benign stenoses. CMS can be effectively and safely removed with a retrieval hook by flexible bronchoscopy under local anesthesia without any major sequel. UCMS may be successfully retrieved by rigid bronchoscopy under general anesthesia.

[Sealing of tracheoesophageal fistula using Sigma covered mental stents].

OBJECTIVE: To explore the possibilities and efficiency of Sigma covered stents for the treatment of tracheoesophageal fistula (TEF). METHODS: Between 2006 and 2009, 10 Sigma covered mental stents had been placed by guidance of bronchoscopy and/or fluoroscopy in 8 patients with 9 tracheoesophageal fistulas. Among them, 7 fistulas were caused by cancer and 2 by mechanical damage. Seven fistulas were located in lower part of trachea and 1 each in the middle and upper parts. RESULTS: Six Y-shaped, 2 L-shaped and 2 I-shaped stents were placed respectively in 8 patients with 9 TEFs. All the TEFs were effectively sealed by the stents except for 1 massive lower and 1 upper fistulas. One mechanical fistula was cured within 1 year of stent placement. The mean survival period of all patients was 8 months. CONCLUSION: By sealing the fistula with a Sigma covered stent, severe respiratory infection may be successfully controlled in patients with TEFs with a major improvement of quality of life.