Life Sciences Commons^™

Ultrastructural And Functional Effects Of Lipopolysaccharide And Interleukin-2 On Human Nk Cells, Yuan-Hsu Kang, Mitchell Carl, Lorrita P. Watson

Scanning Microscopy

Bacterial endotoxin (lipopolysaccharide, LPS) and interleukin-2 (IL-2) are known to stimulate NK cell mediated cytotoxicity against tumor cells. In the present report we sought to correlate the stimulatory effect of LPS and IL-2 on NK cell activity with ultrastructural changes which occurred as a result of such stimulation. Peripheral blood mononuclear cells (PBMC) were purified from healthy donors by a Ficoll-Hypaque density gradient technique. Leu-11a⁺ NK cells were isolated by flow microfluorometry using a monoclonal FITC conjugated anti-Leu-11a antibody and a FACS II cell sorter. The PBMC were incubated, respectively, with E. coli LPS or recombinant IL-2 (IL-2) for …

The Ultrastructure Of Dentine From Rat Incisors Following Exposure To Sodium Fluoride And Potassium Pyroantimonate Staining, J. Appleton

Scanning Microscopy

Weanling rats were given a single intra-peritoneal injection of sodium fluoride and control animals normal saline for four consecutive days. The fluoride produced a consistent response in the mineralizing dentine of the incisors in which a hypermineralized band was succeeded by a hypomineralized band. Potassium pyroantimonate staining for calcium ions showed that following injection of fluoride, in contrast to the controls, there were large amounts of calcium pyroantimonate in the pre-dentine and throughout the odontoblasts. This suggests that fluoride temporarily affects the membrane enzyme systems which maintain calcium concentration gradients between the odontoblasts and the matrix. The resultant influx of …

Scanning Electron Microscopy Of The Spermatheca Of Plethodon Larselli (Amphibia: Plethodontidae): Changes In The Surface Morphology Of The Spermathecal Tubule Prior To Ovulation, Christine M. Davitt, John H. Larsen Jr.

Scanning Microscopy

Spermathecae from eight mature female Larch Mountain salamanders (Plethodon larselli) were used to study cellular changes accompanying the administration of ovulation-inducing pregnant mare serum gonadotropin (PMSG). Animals injected daily with 25 IU of PMSG were sacrificed on day 2 or day 4. Ultrastructural alterations of the spermathecal tubules include an increase in the synthesis and release of product into the lumen and hypertrophy of two epithelial cell types by day 4. One cell type exhibits apocrine blebs and is covered with microvilli; the other contains large spherical vesicles and has only a few, short microvilli on its surface. These changes …

The Effects Of Gamma Irradiation And Calcium Treatment On The Ultrastructure Of Apples And Pears, E. Kovacs, A. Keresztes, J. Kovacs

Food Structure

The post-storage quality of fruits depends on the ultrastructure of the outer tissues and on the fruit mineral composition (mostly on calcium). Pectins and their bonds with calcium play a central role in the tissues during ripening.

During senescence the middle lamella disappears from the cell walls, the fruits become soft and cell wall reticulation can be seen. There are changes within the cells too; plasmalemma separates from the wall, tonoplast from the cytoplasm, and plastids, mitochondria and nuclei are disorganized.

The ultrastructure of the skin and flesh of apples and pears were studied as a function of treatments (calcium, …