1,376 research outputs found
Changes in the Tracheal Ciliated Cells in Rabbits Treated by Cis-Diamminedichloroplatinum (II) as Studied by Electron Microscopy
The ciliated epithelium of the rabbit\u27s trachea was investigated after a single 5 mg dose of cis-diamminedichloroplatinum (cis-DDP). Specimens were taken for scanning electron microscopy, transmission electron microscopy and light microscopy. Examination was performed daily for 20 consecutive days. A cytotoxic effect of the drug on the ciliated epithelium was observed with bent ciliary tips, swollen tips and broken cilia. Finally the cilia were lost and large areas of the surface were covered with microvilli. However, 20 days after the drug injection, the restitution of the ciliary carpet was almost complete
Ciliated Cells of the Trachea of the Rabbit, Treated with Cis-Diamminedichloroplatinum (II) Alone, or in Combination with Ionizing Radiation
The ciliated epithelium of the rabbit trachea was irradiated with daily fractions of 2 Gy to an accumulated dose of 20 Gy (TD: 2, 6, 10, 16, or 20 Gy). Fifteen to forty-five minutes before start of the first irradiation ( treatment day 1) , 5 mg cis-DDP was given by intraperitoneal injection to each rabbit. Examination was made 1-10 days after each fractionation schedule, when specimens were ta ken for investigations.
Scanning electron microscope investigations showed a gradual development of ciliary damage from blebs on the cilia to swollen tips, broken and bent cilia and finally an epithelial lining with areas free from cilia with a surface covered with microvilli-like structures. SEM also showed cell loss, and remnants of dead cells on the surface together with detritus. By transmission electron microscope ciliary damage, cell death and cell loss of the ciliated cell layer as well as exfoliation of portions of goblet-like cells on the surface could be confirmed. The irradiated ciliated epithelium and the untreated control epithelium in each animal showed no difference in this respect. Thus no enhancement of the effects of radiation could be observed. The development of ultrastructural damage may be due to a cytotoxic effect of the drug on the ciliated epithelium. However, 19 days after the start of cis-DDP injection, a hyperplasia of the basal cell layer was observed, which indicates that the observed cytotoxicity of the drug is reversible and a normalisation occurs during the last days of observation in this study
Effects of Cis-Dichlorodiammineplatinum Alone and in Combination with Ionizing Radiation on the Esophageal Mucosa: A Scanning and Transmission Electron Microscopic Study
Cis-dichlorodiammineplatinum (cis-DDP) has for more than 20 years been part of the therapeutic arsenal of oncology. Most of the knowledge about its biological action is based on clinical investigations and therefore an examination of the influence of cis-DDP at the cellular and sub-cellular level is necessary. Five mg of cis-DDP was given intraperitoneally (i.p.) to ten rabbits. Ultrastructural examinations were performed on the upper and lower parts of the esophagus each day after the injection on the following ten days. Another 50 rabbits were given 5 mg cis-DDP and were irradiated in an area just beneath the hypopharynx. They were given 2 Gy at each irradiation and were maximally treated with up to 20 Gy. Examinations were carried out from the first day after the final treatment and each day during ten consecutive days. Five animals were used as controls. Cis-DDP proved to have a deleterious effect on the epithelial layer of the esophageal mucosa with cell loss and structural disarrangement of the microridges and whorls on the surface. This finding was an early phenomenon and lasted for all ten examination days. The changes were not more exaggerated when irradiation was added to the experiments. Repopulation of new cells from the matrix was noticed about five days after the administration of cis-DDP alone
Effects of Fractionated Irradiation on the Esophageal Mucosa: A Scanning and Transmission Electron Microscopic Study
The mucosa of rabbit esophagus was irradiated with daily fractions of 2 Gy to an accumulated dose of 20 Gy. Specimens were taken for scanning electron microscopy, transmission electron microscopy and light microscopy investigations. Examination was made 1-10 days after each fractionation schedule. Light microscopy showed dose-dependent edema of the irradiated mucosa which also could be seen and scored from SEM pictures. SEM investigations showed that this was accompanied by loosening of microridges and a slightly increased cell loss. By SEM, a varying amount of bacteria could be seen which did not make intimate contact with the surface cells.
During the first five days there was a steady decrease of the number of bacteria in relation to the absorbed dose. In the later period of examination, the amount of bacteria increased up to a given dose of 10 Gy. Thereafter, the number faded off to about zero when 20 Gy had been administered
The Effect of 10 and 20 Gy Single Dose Irradiation on the Esophageal Mucosa of the Rabbit. An Electron Microscopic Study
The mucosa of rabbit esophagus was irradiated with single doses of 10 and 20 Gy respectively. Specimens were taken for scanning electron microscopy (SEM), and light microscopy investigations. Examinations were made 1-14 days after 10 Gy and 1-17 days after 20 Gy. Irradiation resulted in edema during the first days. The thickness of the epithelium was at its lowest value around day 5 after the administration of 10 Gy, and on days eight to ten after the administration of 20 Gy. Damage of the epithelium surface, as scored on SEM micrographs, was most pronounced on days eight to eleven after irradiation, showing a clear dose dependency. The second week after irradiation repair was seen concluding in an overshoot of the mucosal height. The amount of bacteria on the surface increased during the period of edema, and decreased when the damage was most pronounced
Changes in the Esophageal Epithelium in Rabbits Treated by Cis-Dichlorodiammineplatinum as Studied by Electron Microscopy
The esophageal mucosa of the rabbit was investigated after a single dose of 5 mg Cis-Dichlorodiammineplatinum (Cis-DDP). Specimens were taken for scanning electron microscopy, transmission electron microscopy, and light microscopy. Examination was performed daily for 20 consecutive days. A cytotoxic effect was observed already the first day after injection with an intracellular oedema. Thereafter the height of the esophageal epithelium and the basal cell layer steadily decreased to a minimum day 11. This parallels the damaged microridges and an increased cell loss as revealed by scanning electron microscopy. At the end of the observation period the esophageal mucosa had completely restituted
TWO NEW PLOCENE SPECIES OF CYCLOSTEPHANOS (BACILLARIOPHYCEAE) WITH COMMENTS ON THE CLASSIFICATION OF THE FRESHWATER THALASSIOSIRACEAE 1
Two new species of the diatom genus Cyclostephanos Round are described from Pliocene fossil deposits in western North America. Cyclostephanos undatus is distinguished from other Cyclostephanos species by its tangentially undulate valve face; Cyclostephanos fenestratus is distinguished by its extremely shallow alveoli. This paper records previously unreported morphological detail of Cyclostephanos and speculates that structure of the punctum, labiate process and strutted process may enhance diagnosis of the freshwater genera of the Thalassiosiraceae Lebour emend. Hasle. Cyclostephanos undatus is similar to several Cyclotella species, but its external costae are raised and its alveolar morphology is similar to that of Cyclostephanos dubius (Fricke) Round. Cyclostephanos fenestratus is similar in external view to Stephanodiscus Ehrenb. However, the two species described here have flat cribra covering the mantle puncta and the labiate processes appear to lack external tubes, whereas Stephanodiscus species have domed mantle cribra and external tubes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65645/1/j.1529-8817.1986.tb04154.x.pd
Liquid Chromatography Electron Capture Dissociation Tandem Mass Spectrometry (LC-ECD-MS/MS) versus Liquid Chromatography Collision-induced Dissociation Tandem Mass Spectrometry (LC-CID-MS/MS) for the Identification of Proteins
Electron capture dissociation (ECD) offers many advantages over the more traditional fragmentation techniques for the analysis of peptides and proteins, although the question remains: How suitable is ECD for incorporation within proteomic strategies for the identification of proteins? Here, we compare LC-ECD-MS/MS and LC-CID-MS/MS as techniques for the identification of proteins.Experiments were performed on a hybrid linear ion trapāFourier transform ion cyclotron resonance mass spectrometer. Replicate analyses of a six-protein (bovine serum albumin, apo-transferrin,lysozyme, cytochrome c, alcohol dehydrogenase, and Ī²-galactosidase) tryptic digest were performed and the results analyzed on the basis of overall protein sequence coverage and sequence tag lengths within individual peptides. The results show that although protein coverage was lower for LC-ECDMS/MS than for LC-CID-MS/MS, LC-ECD-MS/MS resulted in longer peptide sequence tags,providing greater confidence in protein assignment
Electron Capture Dissociation Mass Spectrometry of Tyrosine Nitrated Peptides
In vivo protein nitration is associated with many disease conditions that involve oxidative stress and inflammatory response. The modification involves addition of a nitro group at the position ortho to the phenol group of tyrosine to give 3-nitrotyrosine. To understand the mechanisms and consequences of protein nitration, it is necessary to develop methods for identification of nitrotyrosine-containing proteins and localization of the sites of modification.Here, we have investigated the electron capture dissociation (ECD) and collision-induced association (CID) behavior of 3-nitrotyrosine-containing peptides. The presence of nitration did not affect the CID behavior of the peptides. For the doubly-charged peptides, addition of nitration severely inhibited the production of ECD sequence fragments. However, ECD of the triply-charged nitrated peptides resulted in some singly-charged sequence fragments. ECD of the nitrated peptides is characterized by multiple losses of small neutral species including hydroxyl radicals, water and ammonia. The origin of the neutral losses has been investigated by use of activated ion (AI) ECD. Loss of ammonia appears to be the result of non-covalent interactions between the nitro group and protonated lysine side-chains
A major population of mucosal memory CD4<sup>+</sup> T cells, coexpressing IL-18RĪ± and DR3, display innate lymphocyte functionality
Mucosal tissues contain large numbers of memory CD4(+) T cells that, through T-cell receptor-dependent interactions with antigen-presenting cells, are believed to have a key role in barrier defense and maintenance of tissue integrity. Here we identify a major subset of memory CD4(+) T cells at barrier surfaces that coexpress interleukin-18 receptor alpha (IL-18RĪ±) and death receptor-3 (DR3), and display innate lymphocyte functionality. The cytokines IL-15 or the DR3 ligand tumor necrosis factor (TNF)-like cytokine 1A (TL1a) induced memory IL-18RĪ±(+)DR3(+)CD4(+) T cells to produce interferon-Ī³, TNF-Ī±, IL-6, IL-5, IL-13, granulocyte-macrophage colony-stimulating factor (GM-CSF), and IL-22 in the presence of IL-12/IL-18. TL1a synergized with IL-15 to enhance this response, while suppressing IL-15-induced IL-10 production. TL1a- and IL-15-mediated cytokine induction required the presence of IL-18, whereas induction of IL-5, IL-13, GM-CSF, and IL-22 was IL-12 independent. IL-18RĪ±(+)DR3(+)CD4(+) T cells with similar functionality were present in human skin, nasal polyps, and, in particular, the intestine, where in chronic inflammation they localized with IL-18-producing cells in lymphoid aggregates. Collectively, these results suggest that human memory IL-18RĪ±(+)DR3(+) CD4(+) T cells may contribute to antigen-independent innate responses at barrier surfaces.Mucosal Immunology advance online publication, 1 October 2014; doi:10.1038/mi.2014.87
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