Indications of repair of radon-induced chromosome damage in human lymphocytes: an adaptive response induced by low doses of X-rays.

Naturally occurring radon is a relatively ubiquitous environmental carcinogen to which large numbers of people can be exposed over their lifetimes. The accumulation of radon in homes, therefore, has led to a large program to determine the effects of the densely ionizing alpha particles that are produced when radon decays. In human lymphocytes, low doses of X-rays can decrease the number of chromatid deletions induced by subsequent high doses of clastogens. This has been attributed to the induction of a repair mechanism by the low-dose exposures. Historically, chromosome aberrations induced by radon have been considered to be relatively irreparable. The present experiments, however, show that if human peripheral blood lymphocytes are irradiated with low doses of X-rays (2 cGy) at 48 hr of culture, before being exposed to radon at 72 hr of culture, the yield of chromatid deletions induced by radon is decreased by a factor of two. Furthermore, the numbers of aberrations per cell do not follow a Poisson distribution but are overdispersed, as might be expected because high-linear energy transfer (high LET) alpha particles have a high relative biological effectiveness compared to low-LET radiations such as X-rays or gamma rays. Pretreatment with a low dose of X-rays decreases the overdispersion and leads to a greater proportion of the cells having no aberrations, or lower numbers of aberrations, than is the case in cells exposed to radon alone.(ABSTRACT TRUNCATED AT 250 WORDS

Toxicology Studies on Lewisite and Sulfur Mustard Agents: Genetic Toxicity of Sulfur Mustard (HD) in Chinese Hamster Ovary Cells Final Report

The cytotoxic, clastogenic and mutagenic effects of sulfur nustard in Chinese hamster ovary cells are described in this reoort. The cytotoxicity data indicate that micromolar amounts of HC are highly toxic in microrolar amounts. Chromosone aberration frequencies increased in a dose-dependent manner over a dose range of 0. 5 to 1.0 {micro}m and SCE increased in a dose-dependent fashion in the dose range of 0.0625 to 0.25 {micro}M. Mutation induction at the HGPRT locus was sporadic, but the majority of the exoosures resulted in mutation frequencies which were 1.2 to 4.3 fold higher than the spontaneous frequencies

Toxicology Studies on Lewisite and Sulfur Mustard Agents: Genetic Toxicity of Sulfur Mustard (HD) in Chinese Hamster Ovary Cells Final Report

The cytotoxic, clastogenic and mutagenic effects of sulfur nustard in Chinese hamster ovary cells are described in this reoort. The cytotoxicity data indicate that micromolar amounts of HC are highly toxic in microrolar amounts. Chromosone aberration frequencies increased in a dose-dependent manner over a dose range of 0. 5 to 1.0 {micro}m and SCE increased in a dose-dependent fashion in the dose range of 0.0625 to 0.25 {micro}M. Mutation induction at the HGPRT locus was sporadic, but the majority of the exoosures resulted in mutation frequencies which were 1.2 to 4.3 fold higher than the spontaneous frequencies

Toxicology Studies of Lewisite and Sulfur Mustard Agents: Genetic Toxicity of Lewisite (L) In Chinese Hamster Ovary Cells

The cytotoxic clastogenic and mutagenic effects of the arsenic containing vesicant, Lewisite (L) [dichloro(2-chlorovinyl) arsine], have been investigated using Chinese hamster ovary cells. One hour exposures to Lewisite were cytotoxic in uM amounts. The cell survival response yields a D37 of 0.6 uM and an extrapolation number of 2.5. The mutagenic response at the hypoxantnine-guanine phosporibosyl transferase (HGPRT) locus was sporadic and not significantly greater than control values when cells were exposed over a range of 0.125 to2.0 uM. Sister chromatid exchange (SCE) induction, a measure of chromosomal rearrangement, was weakly positive over a range of 0.25 to 1.0 uM but the values were not significantly greater than the control response. Chromosomal aberrations were induced at 0.75 and 1.0 UMin one experiment and 0.5 and 0.75 uM in another experiment. The Induced values were significantly greater than the control values. Lewisite appears to be cytotoxic and clastogenic in our investigations but SCE and mutation at the HGPRT locus are not significantly greater than control values. Lewisita toxicity was in some ways similar to radiomimetic chemicals such as bleomycin

The clinical global impression scale and the influence of patient or staff perspective on outcome

<p>Abstract</p> <p>Background</p> <p>Since its first publication, the Clinical Global Impression Scale (CGI) has become one of the most widely used assessment instruments in psychiatry. Although some conflicting data has been presented, studies investigating the CGI's validity have only rarely been conducted so far. It is unclear whether the improvement index CGI-I or a difference score of the severity index CGI-S_difis more valid in depicting clinical change. The current study examined the validity of these two measures and investigated whether therapists' CGI ratings correspond to the view the patients themselves have on their condition.</p> <p>Methods</p> <p>Thirty-one inpatients of a German psychotherapeutic hospital suffering from a major depressive disorder (age M = 45.3, SD = 17.2; 58.1% women) participated. Patients filled in the Beck Depression Inventory (BDI). CGI-S and CGI-I were rated from three perspectives: the treating therapist (THER), the team of therapists involved in the patient's treatment (TEAM), and the patient (PAT). BDI and CGI-S were filled in at admission and discharge, CGI-I at discharge only. Data was analysed using effect sizes, Spearman's <it>ρ </it>and intra-class correlations (ICC).</p> <p>Results</p> <p>Effect sizes between CGI-I and CGI-S _difratings were large for all three perspectives with substantially higher change scores on CGI-I than on CGI-S _dif. BDI_difcorrelated moderately with PAT ratings, but did not correlate significantly with TEAM or THER ratings. Congruence between CGI-ratings from the three perspectives was low for CGI-S _dif(ICC = .37; Confidence Interval [CI] .15 to .59; <it>F</it>_30,60= 2.77, <it>p </it>< .001; mean <it>ρ </it>= 0.36) and moderate for CGI-I (ICC = .65 (CI .47 to .80; <it>F</it>_30,60= 6.61, <it>p </it>< .001; mean <it>ρ </it>= 0.59).</p> <p>Conclusions</p> <p>Results do not suggest a definite recommendation for whether CGI-I or CGI-S _difshould be used since no strong evidence for the validity of neither of them could be found. As congruence between CGI ratings from patients' and staff's perspective was not convincing it cannot be assumed that CGI THER or TEAM ratings fully represent the view of the patient on the severity of his impairment. Thus, we advocate for the incorporation of multiple self- and clinician-reported scales into the design of clinical trials in addition to CGI in order to gain further insight into CGI's relation to the patients' perspective.</p

Metaphase chromosome aberrations as markers of radiation exposure and dose

Chromosome aberration frequency provides the most reliable biological marker of dose for detecting acute accidental radiation exposure. Significant radiation-induced changes in the frequency of chromosome aberrations can be detected at very low doses. Our paper provides information on using molecular chromosome probes ``paints`` to score chromosome damage and illustrates how technical advances make it possible to understand mechanisms involved during formation of chromosome aberrations. In animal studies chromosome aberrations provide a method to relate cellular damage to cellular dose. Using an In vivo/In vitro approach aberrations provided a biological marker of dose from radon progeny exposure which was used to convert WLM to dose in rat tracheal epithelial cells. Injection of Chinese hamsters with {sup 144}Ce which produced a low dose rate exposure of bone marrow to either low-LET radiation increased the sensitivity of the cells to subsequent external exposure to {sup 60}Co. These studies demonstrated the usefulness of chromosome damage as a biological marker of dose and cellular responsiveness

Metaphase chromosome aberrations as markers of radiation exposure and dose

Chromosome aberration frequency provides the most reliable biological marker of dose for detecting acute accidental radiation exposure. Significant radiation-induced changes in the frequency of chromosome aberrations can be detected at very low doses. Our paper provides information on using molecular chromosome probes paints'' to score chromosome damage and illustrates how technical advances make it possible to understand mechanisms involved during formation of chromosome aberrations. In animal studies chromosome aberrations provide a method to relate cellular damage to cellular dose. Using an In vivo/In vitro approach aberrations provided a biological marker of dose from radon progeny exposure which was used to convert WLM to dose in rat tracheal epithelial cells. Injection of Chinese hamsters with [sup 144]Ce which produced a low dose rate exposure of bone marrow to either low-LET radiation increased the sensitivity of the cells to subsequent external exposure to [sup 60]Co. These studies demonstrated the usefulness of chromosome damage as a biological marker of dose and cellular responsiveness

[RES4]- AS AN UNUSUALLY STRONG OMICRON-ACCEPTOR LIGAND - [CL2FE(RES4)FECL2]2-, A LINEAR HETEROMETALLIC CLUSTER WITH AN ODD NUMBER OF ELECTRONS

Müller A, Krickemeyer E, Baumann FW, Jostes R, Bögge H. [RES4]- AS AN UNUSUALLY STRONG OMICRON-ACCEPTOR LIGAND - [CL2FE(RES4)FECL2]2-, A LINEAR HETEROMETALLIC CLUSTER WITH AN ODD NUMBER OF ELECTRONS. CHIMIA. 1986;40(9):310-311

A USEFUL CLASSIFICATION OF METAL SULFIDES

Müller A, Diemann E, JOSTES R. A USEFUL CLASSIFICATION OF METAL SULFIDES. Naturwissenschaften. 1984;71(8):420-421