Long-term platinum retention after treatment with cisplatin and oxaliplatin

Background  

The aim of this study was to evaluate long-term platinum retention in patients treated with cisplatin and oxaliplatin.     

Identification of an S-locus glycoprotein allele introgressed from B. napus ssp. rapifera to B. napus ssp. oleifera.

We have previously described a developmentally regulated mRNA in maize that accumulates in mature embryos and is involved in a variety of stress responses in the plant. The sequence of the encoded 16 kDa protein (MA16) predicts that it is an RNA-binding protein, since it possesses a ribonucleoprotein consensus sequence-type RNA-binding domain (CS-RBD). To assess the predicted RNA binding property of the protein and as a starting point to characterize its function we have used ribohomopolymer-binding assays. Here we show that the MA16-encoded protein binds preferentially to uridine- and guanosine-rich RNAs. In light of these results a likely role for this protein in RNA metabolism during late embryogenesis and in the stress response is discussed.     

Molecular basis of artifacts in the detection of telomerase activity and a modified primer for a more robust 'TRAP' assay.

Human somatic cells have essentially no telomerase activity. Telomerase is linked to tumor genesis and is a valuable marker for malignant growth. Extreme paucity of the enzyme neccessitated development of a PCR-based assay, 'telomeric repeat amplification protocol' (TRAP). Unfortunately, this method is not without difficulties.Amplification products are not related to the size of the amplified telomerase products. Furthermore, false positive results can occur, and careful control of reaction conditions is crucial. We analyzed in detail the molecular basis of artifacts. Based on these data, reverse PCR primer was changed and both problems in the TRAP assay were eliminated.     

Inhibition of a nutrient-dependent pinocytosis in dictyostelium discoideum by the amino acid analogue hadacidin

In the present study we examine the effects of the drug hadacidin (N-formyl-N- hydroxyglycine) on pinocytosis in the eukaryotic microorganism dictyostelium discoideum. At concentrations of up to approximately 8 mg/ml, hadacidin inhibited the rate of pinocytosis of fluorescein isothiocyanate (FITC) dextran in cells in growth medium in a concentration-dependent manner but had no effect on cells in starvation medium. Because hadacidin also inhibits cellular proliferation at this concentration, the relationship between growth rate and pinocytosis was studied further using another drug, cerulenin, to produce growth-arrest. These experiments showed no changes in the rate pinocytosis even after complete cessation of cellular proliferation. Other studies showed that the transfer of cells from growth to starvation medium reduced the rate of pinocytosis by approximately 50 percent. A reduction of similar magnitude occurred if cells were transferred from growth to starvation medium containing hadacidin. Also, no additional reduction in pinocytosis occurred when cells that had been treated with hadacidin were transferred to starvation medium containing hadacidin. These cells were able to take up [(14)C]hadacidin in the starvation medium. In contrast to the results with hadacidin-treated cells, cells in a cerulenin-induced state of growth-arrest when transferred to starvation medium exhibited the same 50 percent reduction in pinocytosis observed in cells not previously exposed to either drug. Cells treated with azide, in either growth or starvation medium, exhibited an immediate inhibition of all pinocytotic activity. After the transfer of log-phase cells to starvation medium supplemented with glucose, the reduction in rate was only approximately 10-15 percent. In contrast, a 50 percent reduction was observed after supplementation of starvation medium with sucrose, KCl, or concanavalin A. Maintaining the cells in growth medium containing hadacidin for as long as 16 h had no effect on the rate at which cells aggregated. These results are consistent with the conclusion that D. discoideum exhibits two types of pinocytotic activity: one that is nutrient dependent and the other independent of nutrients. This latter activity persists in starvation medium and is unaffected by hadacidin, whereas the nutrient-dependent activity is present in growth medium and is inhibited by hadacidin.     

Real-time measurement of RFR energy distribution in the macaca mulatta head

Temperature increases due to absorption of 1.2 GHz, CW, 70 mW/cm², radio frequency (RF) energy, were measured in 3.3-cm-radius homogeneous muscle-equivalent spheres, M. mulatta cadaver heads (both detached from and attached to the body) and living, anesthetized M. mulatta heads. Temperatures were measured with a Vitek, Model 101 Electrothermia Monitor and temperature distributions were compared to theoretical predictions from a thermal-response model of a simulated cranial structure. The results show that the thermal response model accurately predicts the temperature distribution in muscle-equivalent spheres, the distribution of temperature in detached M. mulatta heads when exposed from the back of the head, and the distribution of temperature in attached M. mulatta cadaver heads for animals oriented with body parallel to the H-field. The temperature distribution in the detached M. mulatta heads varies markedly with exposure orientation, ie, facing forward, backward, or to the side. The orientation of the M. mulatta cadaver body significantly affects the temperature distribution in the head - with H-field orientation showing high, nonuniform values, and E-field orientation showing low, uniform values. In live animals blood flow produces a significant short-term effect on the temperature distribution in the midbrain, but not the cortex. Midbrain temperatures are both significantly higher and lower than the comparable cadaver measurements, depending on location.     

Sequence changes in both flanking sequences of a pre-tRNA influence the cleavage specificity of RNase P.

The cleavage specificities of the RNase P holoenzymes from Escherichia coli and the yeast Schizosaccharomyces pombe and of the catalytic M1 RNA from E. coli were analyzed in 5'-processing experiments using a yeast serine pre-tRNA with mutations in both flanking sequences. The template DNAs were obtained by enzymatic reactions in vitro and transcribed with phage SP6 or T7 RNA polymerase. The various mutations did not alter the cleavage specificity of the yeast RNase P holoenzyme; cleavage always occurred predominantly at position G + 1, generating the typical seven base-pair acceptor stem. In contrast, the specificity of the prokaryotic RNase P activities, i.e. the catalytic M1 RNA and the RNase P holoenzyme from E. coli, was influenced by some of the mutated pre-tRNA substrates, which resulted in an unusual cleavage pattern, generating extended acceptor stems. The bases G - 1 and C + 73, forming the eighth base pair in these extended acceptor stems, were an important motif in promoting the unusual cleavage pattern. It was found only in some natural pre-tRNAs, including tRNA(SeCys) from E. coli, and tRNAs(His) from bacteria and chloroplasts. Also, the corresponding mature tRNAs in vivo contain an eight base pair acceptor stem. The presence of the CCA sequence at the 3' end of the tRNA moiety is known to enhance the cleavage efficiency with the catalytic M1 RNA. Surprisingly, the presence or absence of this sequence in two of our substrate mutants drastically altered the cleavage specificity of M1 RNA and of the E. coli holoenzyme, respectively. Possible reasons for the different cleavage specificities of the enzymes, the influence of sequence alterations and the importance of stacking forces in the acceptor stems are discussed.