Administration of recombinant tumor necrosis factor to rats bearing the Dunning R3327 MAT-LyLu prostatic adenocarcinoma

Copenhagen X Fischer F1 rats bearing palpable Dunning R3327 MAT-LyLu prostatic adenocarcinomas were treated by intraperitoneal (i.p.) or intratumor (i.t.) injection with either human serum albumin alone or in combination with recombinant tumor necrosis factor (rTNF). At intervals tumors were measured and survivals noted. A maximum tolerable dose and least toxic route of administration was then determined. Those treated i.t. with rTNF survived significantly longer and ultimately developed significantly smaller tumors than untreated controls. Those administered rTNF by the i.p. route had less significant increases in survival with intermediate final tumor sizes.     

Nonuniform behavior of multiple isoactins in the same cell is a cell-dependent phenomenon

The functional significance of multiple isoactins in the same cell is still not understood. To address this question, we examined the response of smooth muscle and cardiac muscle alpha-isoactins to a serial extraction procedure applied to both muscle and nonmuscle cell types. We compared these extraction results with results obtained with the beta- and gamma-nonmuscle actin isoforms from the same cells. In differentiated BC3H1 nonfusing muscle cells (smooth muscle alpha-isoactin), in human rhabdomyosarcoma cells (cardiac alpha-isoactin), and in chick skeletal muscle cells (cardiac alpha-isoactin), different fractions were found selectively enriched in either the nonmuscle or the muscle-specific actin isoforms compared with their relative abundance in whole cell extracts. Conversely, when these same isoactins were examined either in undifferentiated BC3H1 cells or in mouse nonmuscle cells stably transfected with a cardiac alpha-isoactin gene, no enrichment of these isoforms above their relative abundance in whole cell extracts was observed. These results indicate that within the muscle or muscle-like cells examined, the different actin isoforms were either selectively utilized or localized. These results further show that isoactin-specific responses observed were apparently related to the cell type in which they were found and not to differences in inherent physical properties such as solubility of the different isoactins examined.     

A rapid, inexpensive, quantitative, general-purpose densitometer and its application to one-dimensional gel electrophoretograms

We describe the construction of a densitometer based on a TV camera linked to an IBM personal computer (PC) using commercially available components. We discuss some of the problems of accurate quantitative densitometry using low-cost video systems, and describe the manner in which absolute optical density values may be recorded. We describe a digital analysis routine designed to quantitate unresolved bands on noisy one-dimensional electrophoretograms.     

Rat ventral prostate cell lysis at 2 degrees C

In order to physically separate epithelial from nonepithelial cells, well-minced rat ventral prostate at 2 degrees C was passed through a tissue sieve, and the disrupted tissue suspended and washed several times before centrifugation on a Ficoll gradient. While limited separation of single prostate epithelial and nonepithelial cells and small aggregates could be achieved, the yield of intact undamaged cells was low, and many nuclei contaminated the 2 major cell fractions obtained from the gradient. During subsequent experiments, it became apparent that most single cells released from prostates minced at 2 degrees C rapidly lysed, yielding cytoplasmic debris and cell nuclei. Yet the morphology of red and white blood cells, examined by light microscopy, was unaffected, suggesting a soluble factor was not responsible. These results indicated that mechanical dissociation of rat ventral prostate at 2 degrees C with release of single cells was accompanied by a powerful prostate cell-associated lytic 'event', affecting both epithelial and connective tissue cells, without destruction of cell nuclei or accompanying red and white blood cells. Some properties of this process are described in this report.     

Fractionation of human low density lipoprotein by column chromatography.

We have devised a method to fractionate low density lipoprotein (LDL) into subspecies by means of column chromatography. DEAE-agarose columns, 2.6 X 60 cm, were loaded with LDL (25-45 mg LDL protein) and eluted with a 0.045-0.13 M NaCl gradient. The LDL eluted over a volume of 900 ml. Specific portions of the eluted LDL, reapplied to a column identical with the original, reelute at about the same point. Altering the NaCl concentration of the elution fluid changed the elution volume. The cholesterol-protein ratio of the LDL subfractions was progressively lower in fractions eluting at higher NaCl concentrations. These results indicate the LDL is not a homogenous lipoprotein species but consists of subfractions which differ in at least charge and cholesterol content.