Neuroprotective effects of intravenous transplantation of bone marrow mononuclear cells from 5-fluorouracil pre-treated rats on ischemic stroke.

Our previous findings showed bone marrow mononuclear cells (BMMNCs) from 5- fluorouracil (5-FU) pre-treated rats (named BMRMNCs) had a better therapeutic efficacy in ischemia/reperfusion rats as compared to BMMNCs from untreated rats. This study was undertaken to explore the potential mechanisms underlying the neuroprotective effects of BMRMNCs in middle cerebral artery occlusion (MCAO) rat model. Rats were intravenously pre-treated with 5-FU and BMRMNCs were collected at different time points. The contents of growth factors in the supernatant and CXCR4 expression were detected by ELISA and flow cytometry, respectively. MCAO was introduced to rats, and BMMNCs and BMRMNCs collected at 7 days after 5-FU pre-treatment were independently transplanted via the tail vein 24h later. The neurological function was evaluated before cell transplantation and at 24h, 7d and 14d after cell transplantation. Rats were sacrificed at 14d after cell transplantation, the brains were collected for TTC staining, infarct volume detection, NISSL staining, counting of viable cells in the CA1 region, and observation of transplanted cells. BMRMNCs had elevated expressions of growth factors as well as CXCR4 expression. Our results confirmed the better therapeutic effects of BMRMNCs in MCAO rats, demonstrated by reduction in infarct volume, improvement of neurological function and more viable cells in the hippocampus. In addition, more transplanted cells were found after BMRMNCs transplantation at 7 days and 14 days although there was no marked difference at 14 days. These findings indicate that BMRMNCs transplantation may protect ischemic stroke, at least partially, via increasing the secretion of growth factors and migration to the injured site.

The Drift of Saturn's North Polar Spot Observed by the Hubble Space Telescope.

Polar projections of 50 images of Saturn at 889 nanometers and 25 images at 718 nanometers taken by the Hubble Space Telescope in November 1990, as well as 3 images at each wavelength taken in June 1991, have been examined. Among them, 31 show the north polar spot, which is associated with Saturn's polar hexagon, in locations suitable for measurement. In each image, planetocentric coordinates of the polar spot were determined, and the movement of the spot with respect to Saturn's system III rotation rate was studied. During the period of observation, the polar spot had first a short-term westward movement and then a long-term eastward drift. The rate of the long-term drift was -0.060 +/- 0.008 degrees per day with respect to system III, approximately 50 percent greater than previously determined from Voyager. The original 1980 and 1981 Voyager data were combined with the new Hubble images to form an 11-year base line. The eastward drift over the longer period was -0.0569 degrees per day. The long-term drift could be due to uncertainty in the standard value of the internal rotation period, which is 810.7939 +/- 0.148 degrees per 24-hour day. The short-term movement in November 1990 has a rate that is greater in magnitude but opposite in sign and probably represents a real, transient motion of the spot relative to the internal rotation system.

Hubble space telescope imaging of the north polar aurora on jupiter.

The first direct images of the Jovian aurora at ultraviolet wavelengths were obtained by the Hubble Space Telescope Faint Object Camera near the time of the Ulysses spacecraft encounter with Jupiter on 8 February 1992. The auroral oval is not uniformly luminous. It exhibits a brightness minimum in the vicinity of longitude 180 degrees . In the few images available, the brightest part of the oval occurs in late afternoon Jovian time. The observed oval is not concentric with calculated ovals in the O(6) model of Connerney. The size of the oval is consistent with auroral particles on field lines with magnetic L parameter >8, indicating significant migration from lo, its torus, or both, if these are their origins.