The emergence of dendritic complexity is studied by means of a mathematical model, based on randomly branching and randomly propagating growth cones. Branching probabilities, which depend on the position and decrease with the number of growth cones in the growing tree, are su$cient to account for the observed variation in the number and connectivity pattern of dendritic segments. Segment length...

In previous allelotype analyses of human prostatic cancer specimens, allelic loss on the short arm of chromosome 8 is frequently observed. However, it is still unclear whether this allelic loss is an initial event or a later one in development of prostatic cancer. Our previous studies demonstrate that introduction of human chromosome 11 into highly metastatic rat prostatic cancer cells results ...

Correlations were demonstrated among the growth rates, concentrations of kidney-type of phosphate-dependent gluta minase, and morphologies of seven types of transplanted and primary rat neoplasms. The exponential rates of growth in volume of each of the transplanted rat neoplasms were respec tively similar to their rates of cellular growth, measured with colchicine. The relative degrees of hist...

Clonal cell lines were derived from rat liver epithelial cells following their transformation with either v-ra/or v-raflv-myc. Cells transformed with v-ra/alone showed reduced tumor incidence and tumor growth rates when implanted into nude mice, compared to cells also expressing the vmyc oncogene. A series of additional clones isolated from a tumor obtained following inoculation of an athymic n...

Sephadex G-200 column chromatography of hepatoma DNA polymerase yields two peaks of enzyme activity. Peak I contains enzyme having a marked preference for denatured DNA, and the levels of this enzyme increase in proportion to tumor growth rate. Peak II contains the enzyme fraction having a moderate preference for native DNA. Normal and regenerating rat liver have a predominance of Peak II, in c...

The effect of developmental growth on the kidney content of phosphoribosyl pyrophosphate PPRibP was studied in rats at ages between the foetal animal and up to 100 days of age. In addition, the effect of short-term diabetes (up to 14 days) on the renal content of PPRibP was studied in immature rats and in adults aged approx. 60 days. The developmental pattern of PPRibP is such that the PPRibP c...

Background: There is fine correlation between the infertility and lessening of endometrial thickness. In this study the effects of sedative naloxone, and L-arginine, the precursor of nitric oxide (NO), on endometrial thickness of rat uterus was examined. Materials and Methods: Wistar rats (weighing 200-250 g) in Diestrous phase received intra-peritoneal (i.p.) 1. single L-arginine (50 mg/kg), 2...