Importance of apoptosis and extrusion for preserving the structure of the airway epithelium

Reproduction and maintenance of the integrity of the epithelial layer requires a precisely balanced rate of growth and cell death. In overcrowded areas of tissue, some of the cells undergo a consecutive loss of intercellular connections, which leads to a progressive decrease in their number. To keep the barrier intact, the epithelium eliminates dying cells by means of extrusion. Cell extrusion is a unique morphological phenomenon inherent in the epithelium, in which cells prone to apoptosis or non-apoptotic elements are removed from the tissue, thus breaking the symmetry of the layer. During extrusion, the site intended for apoptosis, due to signals from neighboring elements, forms and compresses the ring of the actomyosin complex, which leads to the removal of dying cells from the epithelium. Apoptosis of epithelial cells of the respiratory tract is the main mechanism for a decrease in the cell number after hyperplastic changes in it, arising from exposure to negative factors, viral or bacterial infection. In the review, the authors demonstrate the original photographs of the extrusion of airway epithelial cells.

Suspension syndrome

Suspension syndrome is a potentially fatal event of unknown incidence that can be caused by motionless hanging in the rope during rope-secured activities. During prolonged hanging, generalized hypoperfusion with reduced cerebral blood flow and consecutive loss of consciousness occurs. Two mechanisms are discussed as the cause leading to loss of consciousness: venous pooling in the legs and a sudden reduction of heart rate and blood pressure, similar to a neurocardiogenic syncope. The most important preventive measure is the activation of the muscle pump during hanging. In principle, the treatment follows standard <C>ABCDE care. The patient should be rescued from the hanging position as fast as possible and airway obstruction caused by hyperflexion of the head during unconscious hanging has to be reversed. There is an increased risk of hyperkalemia. Therefore, ECG monitoring should be established as soon as possible to recognize cardiac arrhythmias. Pulmonary embolism should be considered as a potentially reversible cause of cardiac arrest. Hypothermia prophylaxis and treatment have high priority. For suspension longer than two hours, a medical treatment facility able to provide continuous renal replacement therapy should be chosen. There is no evidence that laying a patient flat immediately after rescue is harmful. Key Words: Neurocardiac Syncope, Venous Pooling, Rescue Death, Generalized Hypoperfusion, Standard <C>ABCDE Care

Search for alkaloids on callus culture of Passiflora alata

Preliminary work on Passiflora alata leaves failed to detect harmane alkaloids using LC. The aim of this work was to investigate the production of harmane alkaloids through the cell culture of P. alata, inducing its precursor (L-tryptophan). The leaf explants presented satisfactory results after disinfection, and the callus formation was initiated in MS media with adequate quantities of phytohormones. Sixty days after inoculation, calli were inoculated in the optimized semi-solid MS media, with and without the addition of L-tryptophan (50, 100, 200 mg/L) and kept in standard conditions for 90 days. Calli were collected on days 6, 16, 26, 36, and 90, followed by acid-base extraction, and analysed by LC. The results showed an absence of harmane, harmin, harmol, harmalol, and harmaline. With L-tryptophan feeding, two peaks were detected, collected and analysed through positive mode electrospray [ESI(+)-MS] and sequential analysis in tandem ESI(+)-MS/MS. The spectra obtained were very similar, with a repetition of the more intense ions, and consecutive loss of 68 Da units, attributed to the heterocycle pyrazole. It appeared that this transformation was not related to any enzymatic pathway previously described for the plant from L-tryptophan, and the biosynthesis of β-carboline alkaloids in callus culture of P. alata were not observed in this work.

Research of Valve-Less Pumps With Changeable Cone Angle Nozzle/Diffuser Elements

When it comes to the researches of valve-less pumps with nozzle/diffuser elements of different cone angles, they were usually achieved by manufacturing plural pumps, and the number of the pumps is determined by the accuracy of experiments required. However, the traditional way in which finite pumps of different cone angles were used to simulate the changeable cone angle and it would probably conceal some properties of the nozzle/diffuser elements. Meanwhile, many parameters of the nozzle/diffuser elements other than cone angle can not be kept in consistency. In the research, a new kind of 2-Dimensional nozzle/diffuser elements whose cone angles are changeable is created, and the cone angle of the new nozzle/diffuser elements can be adjusted through adjusting the position of the changeable flow passage. Furthermore, when liquid flow through nozzle/diffuser element, the nozzle/diffuser elements could make consecutive loss coefficient, which makes the changes of flux and flow direction. And the kind of pump with the new structure was developed in the research; the effectiveness and usefulness are also demonstrated and proved in the experiments.

Reexamination of the Carotenoid Pigments of the Unicellular Blue-green Alga Agmenellum quadruplicatum

A previous claim for the occurrence of antheraxanthin and the absence of typical cyanophycean xanthophylls in Agmenellum quadruplicatum has been disproven. This phycocyanin-producing prokaryote showed chlorophyll a, β-carotene, zeaxanthin, one myxoxanthophyll-like, and one myxol-like carotenoid as the major pigments. Traces of keto and other carotenoids were observed, one of which appears to be phoenicopterone or a cis-echinenone. No antheraxanthin and chlorophyll b or c were detected under all culture conditions tested. Algal chlorosis from culture aging was caused by the consecutive loss of phycocyanin and chlorophyll, but the carotenoid composition was much less affected and there was no gain of secondary or keto carotenoids. We concluded that this alga is a typical member of the Cyanophyceae in terms of pigment chemotaxonomy.