Standardisation and Validation of Cytogenetic Markers to Quantify Radiation Absorbed Dose

The amounts of radiation exposure received by radiation workers are monitored generally by physical dosimeters like thermoluminescence dosimeter (TLD) and film badge. However, in practice the over-exposure recorded by physical dosimeters need to be confirmed with biological dosimeters. In addition to confirming the dose recorded by physical dosimeters, biological dosimeters play an important role in estimating the doses received during accidental exposures. Exposure to high levels of radiation induces certain  biochemical, biophysical, and immunological changes (biomarkers) in a cell. Measurement of these changes are generally precise but cannot be effectively used to assess the dose, as the level of these changes return to normalcy within hours to months after exposure. Thus, among various biological indicators, cytogenetic indicators are considered practical and reliable for dose estimation. The paper highlights the importance and establishment of biodosimetry facility using genetic markers such as the sensitive dicentric chromosomes, rapid micronucleus assay and stable translocations measured using fluorescence in situ hybridisation and GTG banding for retrospective dose estimation. Finally, the development of gH2AX assay, as a potential marker of triage dosimeter, is discussed.Defence Science Journal, 2011, 61(2), pp.125-132, DOI:http://dx.doi.org/10.14429/dsj.61.83

Synthesis of thyroglobulin in thyroid carcinoma patients after radioiodine therapy

Endogenously radioiodinated thyroglobulin (Tg) and the serum concentration of Tg have been measured in patients with metastatic thyroid carcinoma after therapeutic doses of radioiodine. Serial samples of blood were analyzed for both these parameters over a period of 10 to 22 days. The specific activity of Tg (cpm/ng) was calculated for each sample. Among the six patients studied, three showed constant specific activity. The specific activity of the other three fell, indicating the entering of newly synthesized Tg into the circulation. The respective amounts of Tg entering into the circulation in these three patients were 120, 852, and 20,935 ng/ml serum/day

Environmental radiation as the conditioning factor for the survival of yeast <i><span style="font-size:14.0pt;line-height:115%;font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";color:black;mso-ansi-language:EN-IN; mso-fareast-language:EN-IN;mso-bidi-language:HI" lang="EN-IN">Saccharomyces cerevisiae</span></i>

95-100Whether natural radiation can be a conditioning factor for the growth and survival of a living organism was investigated using diploid yeast  S. cerevisiae D7. Yeast cells were conditioned by growing them continuously for at least 100 generation in 3 different radiation background such as i) ambient radiation (1.1 mSv/y), ii) sub-ambient radiation (0.44 mSv/y, within a shielded chamber) and iii) an elevated background radiation (88 and 880 mSv/y in a γ-field). At the end, the cells were challenged with 60Co γ, 100 Gy and the viable fractions were determined. Conditioning the cells in 880 mSv/y and in ambient radiation, enabled the cells to reduce the deleterious effect of the challenging dose significantly (P < 0. 05) compared to that of sub-ambient radiation. The cellular viability of yeast cultures seems to be influenced by the prevailing radiation background, apart from starvation. Comparatively, a rapid decline in viability was noticed when the cultures were incubated for 60 days in the shielded chamber. The results indicate that some amount of radiation equivalent to background level or little above is needed to confer fitness in biological systems against stress factors, including radiation. The adaptive dose for the diploid yeast was also determined by single exposure. The priming dose ranged from 0.01 to 1.2 Gy. An adaptive dose of 0.25 or 0.4 Gy, almost nullified the deleterious effect of the challenging dose. The adaptive response may have a greater role in the field of cancer therapy and in radiation risk assessment. Understanding the response of an organism at different radiation-background will be helpful for successful space management<span style="font-size:14.0pt;line-height: 115%;font-family:Fd8138-Identity-H;mso-fareast-font-family:" times="" new="" roman";="" mso-bidi-font-family:fd8138-identity-h;color:black;mso-ansi-language:en-in;="" mso-fareast-language:en-in;mso-bidi-language:hi"="" lang="EN-IN">.</span

Original Communication - Detection of Helicobactor pylori by polymerase chain reaction: A comparison in sample preparation

Gastric biopsy samples obtained from 14 patients with upper abdominal pain, clinically diagnosed as acid peptic disease, were analysed for the presence of Helicobacter pylori (H. pylori) by Polymerase Chain Reaction (PCR) using partially (template A) and completely purified DNA (template B). Antigen specific primer was used to analyse the sample by PCR method. The presence of H. pylori in the samples was confirmed by running a positive control. The presence of H. pylori was also detected by urease method using standard protocol. Among the 14 samples studied, 8 showed the presence of H. pylori with both templates A and B. Among these 8 samples only 3 showed positive for the presence of H. pylori with urease method. The present work discusses the results obtained in the detection of H. pylori in template A and B by PCR method

Immunoreactive thyroglobulin-like material derived from saliva

The presence of an immunoreactive thyroglobulin-like material in saliva from normal subjects and from 35 patients with thyroid carcinoma was detected by radioimmunoassay. The levels of this material in saliva were markedly elevated in patients with extensive metastases. Concentrated saliva samples from normal subjects and from patients with thyroid carcinoma were fractioned on Sepharose-6B and each fraction was assayed for thyroglobulin content by RIA. Several protein peaks of varying molecular size with thyroglublin-like immunoreactivity were observed. The physiological significance of these molecules in saliva remains to be established

Glycoprotein hormone isomorphism and assay discrepancy: The paradigm of luteinizing hormone (LH)

Journal ArticleResearch Support, Non-U.S. Gov'tReviewinfo:eu-repo/semantics/publishe