Surface tensiometry of phase separated protein and polymer droplets by the sessile drop method.

Phase separated macromolecules play essential roles in many biological and synthetic systems. Physical characterization of these systems can be challenging because of limited sample volumes, particularly for phase-separated proteins. Here, we demonstrate that a classic method for measuring the surface tension of liquid droplets, based on the analysis of the shape of a sessile droplet, can be effectively scaled down to measure the interfacial tension between a macromolecule-rich droplet phase and its co-existing macromolecule-poor continuous phase. The connection between droplet shape and surface tension relies on the density difference between the droplet and its surroundings. This can be determined with small sample volumes in the same setup by measuring the droplet sedimentation velocity. An interactive MATLAB script for extracting the capillary length from a droplet image is included in the ESI.

[Exercise-induced asthma]. / L'asthme d'effort.

Exercise-induced asthma is characterized by a transient rise of the airways resistances, associated with asthmatic symptoms, 5 to 10 minutes after the end of a submaximal effort. The treatment is based on a pre-effort warming, cover the mouth with a mask (when the weather is cold), the use of beta-mimetic bronchodilators before exercise and, chronic treatment with antiinflammatory drugs. When the patient is not controlled, an evaluation of the lung function is required with a postbronchodilator control or an exercise challenge test. If the patient remains uncontrolled despite the treatment, others diagnostics should be excluded, such as vocal cords dysfunction or left heart failure.

Transluminal removal of a giant fibrovascular polyp of the esophagus.

Giant fibrovascular polyps of the esophagus are rare benign tumors that originate at the hypopharynx or the upper third of the esophagus. Because of the indolent and benign nature they are mostly discovered when very large with symptoms like dysphagia or regurgitation of the polyp into the mouth which can cause asphyxia and dead. The removal of these polyps is obligatory. Although more than 100 cases of giant fibrovascular esophageal polyps have been described in literature so far, the approach for removal is not yet standard and needs a customized use of medical technology from different disciplines. We present the case of a 42 year old man in whom a giant polyp was removed transorally by a combination of instruments and materials from different disciplines (gastroenterological, surgical and laryngological).

Electron microscopic location of mRNA in the rat kidney: improved post-embedding in situ hybridization.

We determined the optimal technical conditions for post-embedding non-radioactive in situ hybridization applied to ultrastructural location of collagen I mRNA in rat kidney. The signal-to-noise ratio was improved by enhancing hybridization efficiency and distinguishing nonspecific labeling. Probes were labeled with digoxigenin or biotin and detected after hybridization by immunogold or peroxidase techniques. Under these conditions, the signal was located in fibroblasts. With digoxigenin, clusters of gold particles were observed on the endoplasmic reticulum (ER) or scattered throughout the cytoplasmic matrix and nuclei. With the enzymatic method, diaminobenzidine deposits were found on the ER but endogeneous peroxidase partly interfered with the results. Gold particles were less numerous in fibroblast cytoplasm with biotin than with digoxigenin. Moreover, gold particles condensed on fibroblast and tubular cell mitochondria when biotin was used, a phenomenon shown to be due to endogenous biotin by means of a histochemical method. The digoxigenin-immunogold system appeared to be the best method. The biotin system was subject to limitations such as interference from endogenous biotin and poor sensitivity, and mRNA localization was more precise and reliable by the immunogold method than by the enzymatic method.

Emergency stenting of malignant obstruction of the upper airways: long-term follow-up with two types of silicone prostheses.

OBJECTIVE: We evaluated the long-term prognosis of stents placed on an emergency basis in the trachea and its bifurcation for malignant stenosis. METHODS: We retrospectively analyzed all bronchologic treatments of obstructing airway lesions from January 1993 to December 1995. RESULTS: We report on 10 patients with severe malignant "mixed-type" obstruction of the proximal trachea or distal trachea plus both main-stem bronchi. They had far-advanced inoperable tumor (esophageal cancer: n = 4; lung cancer: n = 3; recurrent laryngeal, uvula, and thyroid cancer: n = 1 each). Emergency treatment consisted of a dilating bougie maneuver followed by the insertion of a large one-way (n = 4) or Y-shaped silicone prosthesis (n = 6). After the intervention, there was a long-lasting clinical improvement. Median survival from stent insertion was 8 months for all patients irrespective of tumor type; it was 5 months for patients with lung carcinoma and 8 months for those with esophageal cancer. The results are in accordance with other studies using different therapeutic modalities. Stent exchange was necessary in five patients. Main reasons were continuing tumor growth beyond the proximal and distal boundaries and recurrent productive bronchial infection. Patients died of pneumonia (n = 4), pulmonary lymphatic spread (n = 1), cardiac failure (n = 2), and fatal hemorrhage (n = 1). As of December 1995, three patients were still alive 2, 5, and 8 months after implantation. CONCLUSIONS: As evidenced by clinical efficiency and length of palliation, endoscopic placement of silicone-based one-way and bifurcational prostheses in far-advanced tumor of the central airways is technically feasible and ethically justifiable.

Clinical and laboratory evaluation of a new thin-walled self-expanding tracheobronchial silicone stent: progress and pitfalls.

BACKGROUND: Although widely established in the management of malignant airway lesions, currently available tracheobronchial prostheses made of silicone have their drawbacks resulting from rigidity and wall thickness. Therefore we present clinical follow-up data obtained with a novel thin-walled expandable prototype silicone airway stent (Polyflex stent, Willy Rüsch AG, Kernen, Germany) in 19 patients. METHODS: Seventeen of 19 patients had tracheobronchial complications of infiltrating cancer: five had respiratory-digestive fistulas, 14 had mixed-type obstructions (mucosal infiltration plus extrinsic compression), and two had diffuse tracheal hemorrhages from the tumor surface (three patients had more than one complication). Two of 19 patients had benign postintubation stricture and malacia. Overall, 33 stents were implanted either simultaneously or in a consecutive manner. Scanning electron microscopy was performed both on prototype stents and on other available silicone stents for comparison. RESULTS: The treatment improved the patients' clinical condition substantially. The mechanical properties of the new prosthesis were excellent. Important stent-associated side effects were early mucus retention (n = 7), infolding of the inner silicone layer (n = 2), and stent dislodgment (n = 2). As of February 1997, 10 patients have died of causes unrelated to stent placement. Seven patients with malignant airway disease are still alive from 2 weeks up to 7 months after initial treatment. Scanning electron microscopy of explanted and unused prototypes suggested that an extremely ragged luminal microstructure may contribute to the firm adhesion of secretory material and that technical smoothing of the surface avoids such complications. CONCLUSIONS: The novel self-expandable silicone airway stent may be a promising addition to commonly used stent types. Short-term and medium-term management of fistulas, tumor surface bleeding, and strictures (malignant and benign) is satisfactory. Scanning electron microscopy of stents provides information on peculiar features of microstructure and material that may be of use in clinical research and technical innovation.

Emergency stenting of malignant obstruction of the upper airways: long-term follow-up with two types of silicone prostheses.

We report on 10 patients with severe malignant "mixed-type" obstruction of the proximal trachea or distal trachea plus both main stem bronchi. They had far-advanced inoperable tumors (esophageal cancer in 4 patients, lung cancer in 3, and recurrent laryngeal, uvular, and thyroid cancers in 1 each). Emergency treatment consisted of a dilating bougie maneuver followed by the insertion of a large one-way (4 patients) or Y-shaped (6) silicone prosthesis. Subsequent to the intervention, there was long-lasting clinical improvement. The median survival from stent insertion was 8 months for all patients irrespective of tumor type; it was 5 months for lung carcinoma patients and 8 months for those with esophageal cancer. The results are in accordance with those of other studies using different therapeutic modalities. Stent exchange proved necessary in 5 patients. The main reasons were continuing tumor growth beyond the proximal and distal boundaries and recurrent productive bronchial infection. Patients died of pneumonia (4 patients), pulmonary lymphangitic spread (1), heart failure (2, one of whom also had pneumonia), and fatal hemorrhage (1). As of December 1995, 3 patients were still alive, 2, 5, and 8 months after stent implantation. As evidenced by clinical efficacy and length of palliation, endoscopic placement of silicone-based one-way and bifurcated prostheses in far-advanced tumor of the central airways is technically feasible and ethically justifiable.

[Occupational head and neck cancer: Part II: Not-registered occupational diseases]. / Berufliche Krebserkrankungen im HNO-Fachgebiet.

Substances such as cement dust, polycyclic aromatic carbonhydrates (PAC), diesel exhaust and lubricatant cooling may contribute to the formation of cancer, but are not yet recognized as to be causing occupational cancer. By decree, these diseases can be recognized for compensation when there is enough new evidence for causality. The knowledge about these conditions is crucial for judgement. The technical supervisory board of the Employer's Liability Insurance Association should be asked to report information about the working place concentration of the accused substances before a decision can be made, because life-style factors (alcohol, smoking, nutrition) may contribute also.

[Chance or causality: problems recognizing laryngeal carcinoma as a result of occupational exposition to noxious substances of blue collar worker employed in the rubber industry]. / Zufall oder Kausalität--zur Problematik der Anerkennung von Larynxkarzinomen bei Arbeitern der Gummi-Industrie.

BACKGROUND: Laryngeal cancer as an occupational disease in the rubber industry is under subject of continuous epidemiological research because of the lack of stable statistical data. METHOD: Epidemiological studies published in the period between 1982 and 2006 were analysed in regard of the risks employment and laryngeal carcinoma. 23 own cases of medical expert opinion and the documentation of the German Occupational Cooperatives were analysed. RESULTS: A significant statistical correlation between a specific exposition to cancerogenics in the rubber industry and a development of laryngeal carcinoma could not be found in the literature, still there is evidence for an increased mortality. It points to asbestos, talcum, dust as one risk factor. CONCLUSION: Recognition and compensation for laryngeal carcinoma according to [section sign] 9 Abs. 2 SGB VII is possible after intense individual investigation, although up to now no clear statistical evidence for the coincidence between employment in the rubber industry and general could be proven.

[Epithelialization model of non-biological tissue replacement materials in vitro]. / Epithelisierungsmodell nicht-biologischer Gewebeersatzmaterialien in vitro.

Successful use of non-biologic implants in reconstructive head and neck surgery is dependent on tissue compatibility and epithelization. This is true not only for epithelial cells, but also for mesenchymatic cells. Therefore we tested several substrates with human fibroblasts or keratinocytes from the oral mucosa in cell culture. In tissue culture keratinocyte outgrowth from small mucosal flaps onto the surface was observed. Preparations were evaluated by histology and scanning electron microscopy. Cellulose-ester, polyvinylidene-difluoride and polyglactin developed monolayers of fibroblasts and keratinocytes in cell cultures. In tissue culture mucosal flaps showed good adherence to the surface of these materials and a fine outgrowth of keratinocytes. Expanded polytetrafluor-ethylene (ePTFE) was partially covered by a layer of fibroblasts and keratinocytes in cell culture, but cell adherence was not sufficient. In tissue culture the mucosal flaps failed to attach on ePTFE. These results illustrate that the mesenchymatic and epithelial component of cell and tissue cultures show different qualities of cellular adherence and growth on the surface of non-biologic implants. We propose our method for the development of an in-vitro model for the epithelization of non-biologic implantation materials.

Treatment of a ruptured anastomotic esophageal stricture following bougienage with a Dacron-covered nitinol stent.

A patient suffering from esophagorespiratory fistula after bougienage of a benign stricture at the site of the anastomosis between a jejunal interposition and the esophagus was referred for interventional treatment. A prototype nitinol stent centrally covered with Dacron was implanted under regional anesthesia and fluoroscopic guidance. The self-expanding prosthesis dilated the stenosis completely and closed the fistula, with consequent improvement in respiratory and nutritional status and thus the general quality of life. The patient was able to eat and drink normally until death 3 months later due to progression of his underlying malignant disease.