A DNA cytophotometric study of salt adaptation in Allium cepa and Nicotiana bigelovii

Abstract Nuclear DNA was measured by Feulgen cytophotometry in NaCl-exposed Allium cepa roots and Nico-tiana bigelovii calli cultured in vitro. Analysis of the differentiation zone of A. cepa roots grown in water showed that only 2.8% of the nuclei had DNA contents higher than 4 C, where 2 C nuclei were predominant. In roots grown in salt water, 2 C nuclei were less numerous than 4 C nuclei and the DNA content was greater than 4 C in 19.2% of the cells, with 1.4% of the cells having a DNA content of 16 C. Two C, 4 C, 8 C, and a few 16 C nuclei, together with many nuclei with intermediate DNA content values, occurred in both the control and salt-treated calli of N. bigelovii. About 49.1% of the nuclei had DNA values around 2 C in the controls, while the percentage of cells with nuclei with higher DNA content values increased in calli as the NaCl concentration in the medium increased. Fifteen per cent of the nuclei had DNA values around 16 C in calli grown on media with 10 gr l−1 NaCl added, compared to 2.8..

DNA/Histone Ratio in Different Regions of Polytene Chromosomes in the Embryo Suspensor Cells of Phaseolus Coccineus

SUMMARYThe DNA/histone ratio was calculated through Feulgen/fast green absorption in different regions of polytene chromosomes in Phaseolus coccineus embryo suspensor cells. A great variability of ratios, related with the structural characteristics of DNA in the different regions, has been found. This seems to indicate that complexes of histone with DNA may depend on changes in DNA metabolic activity. In one and the same cell, and even in one and the same chromosome, different chromosome segments have different DNA/histone ratios.These findings are discussed in relation to some characteristics of polytene chromosomes in Phaseolus suspensor cells

History and growth of radiation oncology in Indonesia

In order to assess its progress, and to obtain a snapshot of the current situation, the Indonesian Radiation Oncology Society has routinely conducted annual surveys since 2004 to assess the current condition of resources for equipment and staffing in all radiation oncology centres in the country. Based on these routine surveys, the society has made recommendations to the government about providing cancer patients with better and more affordable access to radiotherapy services

Engineering Graph-Based Models for Dynamic Timetable Information Systems

Many efforts have been done in the last years to model public transport timetables in order to find optimal routes. The proposed models can be classified into two types: those representing the timetable as an array, and those representing it as a graph. The array-based models have been shown to be very effective in terms of query time, while the graph-based models usually answer queries by computing shortest paths, and hence they are suitable to be used in combination with speed-up techniques developed for road networks. In this paper, we focus on the dynamic behavior of graph-based models considering the case where transportation systems are subject to delays with respect to the given timetable. We make three contributions: (i) we give a simplified and optimized update routine for the well-known time-expanded model along with an engineered query algorithm; (ii) we propose a new graph-based model tailored for handling dynamic updates; (iii) we assess the effectiveness of the proposed models and algorithms by an experimental study, which shows that both models require negligible update time and a query time which is comparable to that required by some array-based models

molecular and chromosomal characterization of repeated and single copy dna sequences in the genome of dasypyrum villosum

Restriction fragment length polymorphism of ribosomal DNA repeated unit and single-copy DNA fragments and chromosomal distribution of a highly repeated sequence, have been studied to assess molecular markers and the extent of their heterogeneity in Dasypyrum villosum. Substantial variation has been found for the length of the intergenic spacer of ribosomal genes clustered in different alleles at Nor- VI locus of heterozygous individuals, but not within the cluster of rDNA of homozygous individuals. After Southern blots and hybridization to an intergenic spacer probe, each cluster of rDNA was detected as a single band with at least four variants differing for the number of 130 bp subrepeats in the intergenic spacer. One recombinant plasmid contained a 2270 bp DNA insert from the D. villosum genome that upon Sph I restriction endonuclease digestion was cleaved in three 380 bp repeat elements and one 1090 bp fragment. When Southern blots of Sph 1 digested D. villosum DNAs of different genotypes were hybridized to the 32P-labelled 380 bp repeat, a distinct ladder consisting of multiples of a basic repeat unit of about 380 bp in length was revealed on autoradiograms. The in situ hybridization of the 3H-labelled 380 bp repeat element showed that one chromosome pair (7V) was not labelled. In the other pairs, silver grains remained clustered at or near the telomeres. Dot-blot hybridization analysis of DNAs from a range of diploid, tetraploid, and hexaploid Triticeae species indicated that the 380 bp repeated element was a specific feature of the D. villosum genome. Other cloned DNA sequences of D. villosum showed a large restriction length polymorphism and one was located on V chromosomes

Dosimetric impact of different multileaf collimators on prostate intensity modulated treatment planning

AimThe main purpose of this study is to perform a dosimetric comparison on target volumes and organs at risks (OARs) between prostate intensity modulated treatment plans (IMRT) optimized with different multileaf collimators (MLCs).BackgroundThe use of MLCs with a small leaf width in the IMRT optimization may improve conformity around the tumor target whilst reducing the dose to normal tissues.Materials and methodsTwo linacs mounting MLCs with 5 and 10[[ce:hsp sp="0.25"/]]mm leaf-width, respectively, implemented in Pinnacle3 treatment planning system were used for this work. Nineteen patients with prostate carcinoma undergoing a radiotherapy treatment were enrolled. Treatment planning with different setup arrangements (7 and 5 beams) were performed for each patient and each machine. Dose volume histograms (DVHs) cut-off points were used in the treatment planning comparison.ResultsComparable planning target volume (PTV) coverage was obtained with 7- and 5-beam configuration (both with 5 and 10[[ce:hsp sp="0.25"/]]mm MLC leaf-width). The comparison of bladder and rectum DVH cut-off points for the 5-beam arrangement shows that 52.6% of the plans optimized with a larger leaf-width did not satisfy at least one of the OARs’ constraints. This percentage is reduced to 10.5% for the smaller leaf-width. If a 7-beam arrangement is used the value of 52.6% decreases to 21.1% while the value of 10.5% remains unchanged.ConclusionMLCs collimators with different widths and number of leaves lead to a comparable prostate treatment planning if a proper adjustment is made of the number of gantry angles

A multimodal approach to the treatment of bilateral choroidal metastases from thyroid carcinoma

A 58-year old man, affected by metastatic thyroid carcinoma, experienced a progressive bilateral visual impairment. Ophthalmic examination revealed the presence of a choroidal mass with an associated exudative retinal detachment in both eyes. Twelve years before, a diagnosis of metastatic thyroid carcinoma had been established and the patient had been subject to several therapeutic procedures