Removal of239Pu from mice with 3,4,3 LICAM(C) or N,N′, N″, N‴-tetra-(2,3-dihydroxybenzoyl)-spermine

Summary Male mice SAS/4 were injected i.v. with²³⁹Pu citr(IV) 0.27 µCikg^–1–9.99 kBqkg^–1. After 1 h 30 µmol kg^–1 of 3,4,3 LICAM(C), N, N, N, N-tetra-(2,3-dihydroxybenzoyl)-spermine or Na₃CaDTPA as a reference compound was given intraperitoneally. After 4 days the animals were sacrified and the Pu content in livers, kidneys, femurs and carcasses was determined by the liquid scintillation method. It was found that, as compared with the control, 3,4,3 LICAM(C) removed 83% of the Pu activity deposited in the liver, 71% of that in the femur and 79% of the Pu in the whole body. The Pu content in the kidneys exceeded the control value by about 50%. Na₃CaDTPA removed 96, 86, 40 and 72% of plutonium from the liver, kidneys, femurs and carcasses respectively.Tetra-DHB-spermine caused the excretion of 50, 57 and 39% of Pu from liver, bone and whole body respectively. The retention of Pu in the kidneys was increased to 400% of the control value.     

Extreme heterogeneity of polyadenylation sites in mRNAs encoding chloroplast RNA-binding proteins in Nicotiana plumbaginifolia

We have previously characterized nuclear cDNA clones encoding two RNA binding proteins, CP-RBP30 and CP-RBP-31, which are targeted to chloroplasts in Nicotiana plumbaginifolia. In this report we describe the analysis of the 3-untranslated regions (3-UTRs) in 22 CP-RBP30 and 8 CP-RBP31 clones which reveals that mRNAs encoding both proteins have a very complex polyadenylation pattern. Fourteen distinct poly(A) sites were identified among CP-RBP30 clones and four sites among the CP-RBP31 clones. The authenticity of the sites was confirmed by RNase A/T1 mapping of N. plumbaginifolia RNA. CP-RBP30 provides an extreme example of the heterogeneity known to be a feature of mRNA polyadenylation in higher plants. Using PCR we have demonstrated that CP-RBP genes in N. plumbaginifolia and N. sylvestris, in addition to the previously described introns interrupting the coding region, contain an intron located in the 3 non-coding part of the gene. In the case of the CP-RBP31, we have identified one polyadenylation event ocurring in this intron.     

EcoRI-sensitive mutation of T7 phage

Summary It was found that yeast cells contain an endonuclease specific for apurinic sites in DNA which has no effect on DNA with normal strands or on strands with alkylated sites. The enzyme activity was studied in the RAD strain and in rad6, rad18-2 and rad21 mutants, all very sensitive to MMS, as compared to the wild type. The level of endonuclease activity does not differ much between the tested strains, regardless of their differences in susceptibility to MMS. The enzyme activity is not induced by pretreatment of the cells with this mutagen.     

Electrocardiogram data mining based on frame classification by dynamic time warping matching

This paper presents an electrocardiogram (ECG) data mining scheme based on the ECG frame classification realised by a dynamic time warping (DTW) matching technique, which has been used successfully in speech recognition. We use the DTW to classify ECG frames because ECG and speech signals have similar non-stationary characteristics. The DTW mapping function is obtained by searching the frame from its end to start. A threshold is setup for DTW matching residual either to classify an ECG frame or to add a new class. Classification and establishment of a template set are carried out simultaneously. A frame is classified into a category with a minimal residual and satisfying a threshold requirement. A classification residual of 1.33% is achieved by the DTW for a 10-min ECG recording.     

Oxidative DNA Base Modifications and Polycyclic Aromatic Hydrocarbon DNA Adducts in Squamous Cell Carcinoma of Larynx

Tobacco smoke, recognized as a major etiological factor for cancers of the upper aerodigestive tract, represents an abundant source of reactive oxygen species (ROS), which are believed to play a significant role in mutagenesis and carcinogenesis. An additional source of ROS in tissues exposed to tobacco smoke may be metabolic oxidation of polycyclic aromatic hydrocarbons (PAH). To investigate the relationships between oxidative DNA lesions and aromatic DNA adducts, six modified DNA bases 5-hydroxyuracil, 5-hydroxycytosine, 7,8-dihydro-8-oxoguanine, 7,8-dihydro-8-oxoadenine, 2,6-diamino-4-hydroxy-5-formamidopyrimidine and 4,6-diamino-5-formamidopyrimidine and the total level of PAH-related DNA adducts were measured in cancerous and the surrounding normal larynx tissues (68 subjects), using gas chromatography/isotope-dilution mass spectroscopy with selected ion monitoring and the 32 P-postlabeling-HPLC assay, respectively. The levels of oxidative DNA lesions in cancerous and adjacent tissue were comparable; the differences between the two types of tissue were significant only for 5-hydroxypyrimidines (slightly higher levels were observed in the adjacent tissue). Comparable levels of DNA lesions in cancerous and the surrounding normal tissues observed in the larynx tumors support a field cancerization theory. The surrounding tissues may still be recognized as normal by histological criteria. However, molecular alterations resulting from the chronic tobacco smoke exposure, which equally affects larynx epithelia, may lead to multiple premalignant lesions. Thus, a demonstration of similar levels of DNA damage in cancerous and the adjacent tissue could explain a frequent formation of secondary tumors in the larynx and the frequent recurrence in this type of cancer. A weak, but distinct effect of tumor grading and metastatic status was observed in both kinds of tissue in the case of 5-hydroxyuracil, 5-hydroxycytosine, 7,8-dihydro-8-oxoguanine, 7,8-dihydro-8-oxoadenine. This effect was displayed as a gradual shift in the data distribution toward high values from G1 through G2-G3 and from non-metastatic to metastatic tumors. Since the levels of oxidative DNA base modifications tended to increase with the tumor aggressiveness, we postulate that the oxidative DNA lesions increase genetic instability and thus contribute to tumor progression in laryngeal cancer. No associations between aromatic adduct levels and oxidative DNA lesions were present, suggesting that the metabolism of PAH does not contribute significantly to the oxidative stress in larynx tissues, remaining the tobacco smoke ROS as a major source of oxidative DNA damage in the exposed tissue.