Steroid saponins

Steroid saponins isolated from various plants are reviewed. The newer techniques used in their isolation and structure elucidation are discussed. A compilation of the saponins isolated up to 1980 along with their available physical data is included. The basic steroidal saponins isolated after 1972 are also compiled.     

Morphological differentiation of a murine neuroblastoma clone in monolayer culture induced by dexamethasone

Dexamethasone induces morphological differentiation in murine neuroblastoma cells in culture. The percentage of differentiated cells depends on the concentration of dexamethasone in the medium and duration of treatment. After drug removal (with or without replating), many cells maintain their differentiated phenotype. Dexamethasone-treated cells have larger soma and contain more protein. Dexamethasone also produces a concentration-dependent inhibition of population growth. Growth inhibition is complete by 2 days following treatment with dexamethasone 50 micrograms/ml. Complete growth inhibition is achieved prior to the complete expression of morphological differentiation. Androstenedione, testosterone, and 17-beta-estradiol--all steroids without glucocorticoid activity--have no differentiating effect, although they inhibit growth or cause cell death at higher concentrations.     

Alcohol inhibits morphological and biochemical differentiation of C6 glial cells in culture

Cultures of glial cell lines (C6) were exposed to 10-micromilligram Dexamethasone which is known to cause morphological differentiation and induction of 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNP) in these cells. Ethanol in a concentration of 1.5% abolished these responses, and at 1% diminished them.     

Differential sensitivity to Itk kinase signals for T helper 2 cytokine production and chemokine-mediated migration.

Allergic asthma is dependent on chemokine-mediated Th2 cell migration and Th2 cytokine secretion into the lungs. The inducible T cell tyrosine kinase Itk regulates the production of Th2 cytokines as well as migration in response to chemokine gradients. Mice lacking Itk are resistant to developing allergic asthma. However, the role of kinase activity of Itk in the development of this disease is unclear. In addition, whether distinct Itk-derived signals lead to T cell migration and secretion of Th2 cytokines is also unknown. Using transgenic mice specifically lacking Itk kinase activity, we show that active kinase signaling is required for control of Th2 responses and development of allergic asthma. Moreover, dominant suppression of kinase Itk activity led to normal Th2 responses, but significantly reduced chemokine-mediated migration, resulting in prevention of allergic asthma. These observations indicate that signals required for Th2 responses and migration are differentially sensitive to Itk activity. Manipulation of Itk's activity can thus provide a new strategy to treat allergic asthma by differentially affecting migration of T cells into the lungs, leaving Th2 responses intact.     

Senescence of Detached Fern Leaves

Detached fern leaves show a loss in the content of pigments,protein and a decline in 2,6-dichlorophenol indophenol Hillreaction of isolated chloroplasts during aging. Light treatmentof leaves could considerably retard aging induced loss in 2,6-dichlorophenolindophenol photoreduction but it exhibits less effect on pigmentand protein loss. (Received February 7, 1983; Accepted July 14, 1983)     

In vivo detection of venous sinus distension due to intracranial hypotension in small animal using pulsed‐laser‐diode photoacoustic tomography

Intracranial hypotension (IH) is a pathophysiological condition of reduced intracranial pressure caused by low cerebrospinal fluid (CSF) volume due to dural injuries from lumbar puncture, surgery, or trauma. Understanding the prognosis of IH in small animal models is important to gain insights on the complications associated with it such as orthostatic headache, cerebral venous thrombosis, coma, and so forth. Photoacoustic tomography (PAT) offers a novel and cost‐effective way to perceive and detect IH in small animal models. In this study, a pulsed laser diode (PLD)‐based PAT imaging system was used to examine the changes in the venous sinuses of the rat brain due to IH, induced through CSF extraction. After the CSF extraction, an increase in the sagittal sinus area by ~30% and width by 40% ± 5% was observed. These results provide supportive evidence that the PLD‐PAT can be employed for detecting changes in sagittal sinus due to IH in rat model.     

Exploring the utility of Deep Red Anthraquinone 5 for digital staining of ex vivo confocal micrographs of optically sectioned skin

We investigated the utility of the fluorescent dye Deep Red Anthraquinone 5 (DRAQ5) for digital staining of optically sectioned skin in comparison to acridine orange (AO). Eight fresh-frozen thawed Mohs discard tissue specimens were stained with AO and DRAQ5, and imaged using an ex vivo confocal microscope at three wavelengths (488 nm and 638 nm for fluorescence, 785 nm for reflectance). Images were overlaid (AO + Reflectance, DRAQ5 + Reflectance), digitally stained, and evaluated by three investigators for perceived image quality (PIQ) and histopathological feature identification. In addition to nuclear staining, AO seemed to stain dermal fibers in a subset of cases in digitally stained images, while DRAQ5 staining was more specific to nuclei. Blinded evaluation showed substantial agreement, favoring DRAQ5 for PIQ (82%, Cl 75%-90%, Gwet's AC 0.74) and for visualization of histopathological features in (81%, Cl 73%-89%, Gwet's AC 0.67), supporting its use in digital staining of multimodal confocal micrographs of skin.