A graphical method is described that allows the determination of specific radioactivities of radioactively labelled hormones. This method combines the self-displacement technique, plotting bound/free ratios versus mass of unlabelled hormone or total radioactivity of labelled preparation added to the receptor preparation, and the maximal binding capacity of the labelled hormone. The procedure pr...

Some aspects of tricarboxylic acid-cycle activity during differentiation and aging in Dictyostelium discoideum were examined. The concentrations of glutamate, aspartate, alanine, citrate, 2-oxoglutarate, succinate, fumarate, malate, oxaloacetate, pyruvate and acetyl-CoA were determined at four stages over the course of differentiation. The rate of 02 utilization was also determined over differe...

The formation of protochlorophyllide and protochlorophyllide phytyl ester was investigated during etioplast biogenesis in order to study the biosynthetic relation of these two compounds. Protochlorophyllide accumulates slowly during the first 2 days of germination, its rate of formation increases sharply during the 3rd day, and then it decreases. Protochlorophyllide phytyl ester starts accumula...

background: quantification of radiation-induced apoptosis in peripheral blood lymphocytes (pbls) has been proposed as a possible screening test for cancer-prone individuals and also for the prediction of normal tissue responses after radiotherapy. materials and methods: the neutral version of the comet assay (single-cell gel electrophoresis) was used 24, 48, 72 hours after irradiation with 8 gy...

background: radio-adaptive response and bystander effects are known phenomena occurring in cells following exposure to ionizing radiation (ir). in this study we examined possible radio-adaptation of lymphocytes following bystander effects induced by cho-k1 cells. materials and methods: whole blood and cho-k1 cells were cultured in rpmi-1640 complete medium. cells were separately irradiated with...

background: the characteristics of secondary neutrons in a high energy radiation therapy room were studied using the mcnpx monte carlo (mc) code. materials and methods: two mc models including a model with full description of head components and a simplified model used in previous studies were implemented for mc simulations. results: results showed 4-53% difference between full and with the sim...

background: radioprotective effect of famotidine was previously shown on radiation induced micronuclei and chromosomal aberrations in human peripheral lymphocytes and mouse bone marrow cells however, its radioprotective property has never been studied in mouse spermatogenesis. it was also shown that vitamin c as an antioxidant also exert its radioprotective effect on many biological systems, bu...

Squash (Cucurbita pepo L. var. melopepo torticalis, Bailey) leaves were supplied with (14)C-sucrose, then specific radioactivities of the glucose and galactose moieties of translocated stachyose were determined. In every case, the specific radioactivity of the galactose moiety was greater than that of the glucose moiety. It is concluded that the stachyose was not synthesized at either the phloe...

Background: Radiotherapy Treatment Planning requires different dosimetric quantities as input in order to calculate a desired dose distribution. This study has been focused to evaluate the depth dose characteristics of superficial X-rays being used for radiotherapy treatment. Materials and Methods: Computerized 3-D water phantom of multi-data system was used. The measurements were made...

We are constructing a model which aims to reproduce observational data of many kinds related to cosmic-ray origin and propagation: direct measurements of nuclei, antiprotons, electrons and positrons, γ-rays, and synchrotron radiation. These data provide many independent constraints on any model. Propagation of primary and secondary nucleons, primary and secondary electrons and positrons are cal...