Tumor Necrosis Factor Receptors in Neuroblastoma SKNBE Cells and Their Regulation by Retinoic Acid

Abstract: The human neuroblastoma cell line SKNBE can be differentiated either by serum removal or by adding to the culture medium different morphogens, for instance, retinoic acid (RA), cyclic AMP derivatives, and phorbol esters. Both the differentiated and undifferentiated cells express the two types of membrane tumor necrosis factor (TNF) receptors (TNFRs) of 55 and 75 kDa (p55 and p75 TNFR, respectively) and also their soluble forms. After RA addition the number of the surface TNFRs per cell is increased approximately twofold, but the kinetics of expression are different, depending on the receptor type. The level of the mRNAs of 2.4 and 4.2 kb, which, respectively, encode the p55 and p75 TNFRs, is also increased during the time course of differentiation, and the kinetics of their expression are biphasic. In contrast, the number of TNFRs and the level of their encoding mRNAs remain unchanged after exposure of the cells to both a phorbol and a cyclic AMP derivative.     

Thymidine labeling index and estrogen receptor level in 64 human breast cancers

Concurrent assays of labeling index (LI) and estrogen receptors (ER) have been performed in 64 human breast cancers. The dipping method of autoradiography has been used for measurements of LI. The LI values are given as a number per hundred of cell nuclei labeled by tritiated thymidine. ER levels were determined by dextran-coated charcoal method followed by Scatchard analysis, and expressed in femtomoles per milligram of cytosol protein. Tumours with ER greater than or equal to 28 fmol/mg were demonstrating a low LI (less than 2.3%) and come all from patients of age over 50 years. LI and ER values have been compared with clinical data. The best clinical outcome have been found among patients with low LI values (less than 2.3%). Patients with borderline ER values (3 fmol/mg less than ER less than 28 fmol/mg) showed a satisfactory clinical outcome in 88% of cases when LI less than 2.3% and 57% of cases when LI greater than or equal to 2.3%.     

Anesthetic and pathological changes following high doses of ketamine and xylazine in Sprague Dawley rats

The main objective of this study was to compare the effects of ketamine and xylazine in aging rats when coadministered intraperitoneally at high anesthetic doses. Three groups (n=6 rats/group) consisting of rats at 3, 6 and 12 months of age were used. During anesthesia, animals were monitored for heart rate, respiratory frequency, blood oxygen saturation, and rectal temperature. The corneal and paw withdrawal reflex were also examined during anesthesia. During anesthesia, withdrawal and corneal reflexes were absent for progressively longer durations with increasing age. Significant decreases in cardiac and respiratory frequency and, blood oxygen saturation occurred for the 6- and 12-month-old animals. Respiratory frequency and blood oxygen saturation returned to normal at the end of the anesthesia; however, the significant decrease in cardiac frequency persisted in the 6- and 12-month-old animals. Rectal temperature was decreased significantly only in the 3-month-old animals. Pulmonary edema and effusion occurred in 50% of the 12-month-old animals. In conclusion, if ketamine-xylazine are used for anesthesia, the doses should be optimized for the age of the subjects prior to initiation of the research project.