Considerations for population monitoring using cytogenetic techniques

Silver coated materials for external fixation devices: in vitro biocompatibility and genotoxicity.

Micronucleus (MN) expression in peripheral blood lymphocytes is well established as a standard method for monitoring chromosome damage in human populations. The first results of an analysis of pooled data from laboratories using the cytokinesis-block micronucleus (CBMN) assay and participating in the HUMN (HUman MicroNucleus project) international collaborative study are presented. The effects of laboratory protocol, scoring criteria, and host factors on baseline micronucleated binucleate cell (MNC) frequency are evaluated, and a reference range of "normal" values against which future studies may be compared is provided. Primary data from historical records were submitted by 25 laboratories distributed in 16 countries. This resulted in a database of nearly 7000 subjects. Potentially significant differences were present in the methods used by participating laboratories, such as in the type of culture medium, the concentration of cytochalasin-B, the percentage of fetal calf serum, and in the culture method. Differences in criteria for scoring micronuclei were also evident. The overall median MNC frequency in nonexposed (i.e., normal) subjects was 6.5 per thousand and the interquartile range was between 3 and 12 per thousand. An increase in MNC frequency with age was evident in all but two laboratories. The effect of gender, although not so evident in all databases, was also present, with females having a 19% higher level of MNC frequency (95% confidence interval: 14-24%). Statistical analyses were performed using random-effects models for correlated data. Our best model, which included exposure to genotoxic factors, host factors, methods, and scoring criteria, explained 75% of the total variance, with the largest contribution attributable to laboratory methods.

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HUman MicroNucleus Project: International database comparison for results with the cytokinesis-block micronucleus assay in human lymphocytes: I. Effect of laboratory protocol, scoring criteria, and host factors on the frequency of micronuclei

Physicians performing interventional procedures are chronically exposed to ionizing radiation, which is known to pose increased cancer risks. We recently reported 9 cases of brain cancer in interventional cardiologists. Subsequently, we received 22 additional cases from around the world, comprising an expanded 31 case cohort. Data were transmitted to us during the past few months. For all cases, where possible, we endeavored to obtain the baseline data, including age, gender, tumor type, and side involved, specialty (cardiologist vs radiologist), and number of years in practice. These data were obtained from the medical records, interviews with patients, when possible, or with family members and/or colleagues. The present report documented brain and neck tumors occurring in 31 physicians: 23 interventional cardiologists, 2 electrophysiologists, and 6 interventional radiologists. All physicians had worked for prolonged periods (latency period 12 to 32 years, mean 23.5 ± 5.9) in active interventional practice with exposure to ionizing radiation in the catheterization laboratory. The tumors included 17 cases (55%) of glioblastoma multiforme (GBM), 2 astrocytomas (7%), and 5 meningiomas (16%). In 26 of 31 cases, data were available regarding the side of the brain involved. The malignancy was left sided in 22 (85%), midline in 1, and right sided in 3 operators. In conclusion, these results raise additional concerns regarding brain cancer developing in physicians performing interventional procedures. Given that the brain is relatively unprotected and the left side of the head is known to be more exposed to radiation than the right, these findings of disproportionate reports of left-sided tumors suggest the possibility of a causal relation to occupational radiation exposure.

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Brain and Neck Tumors Among Physicians Performing Interventional Procedures

The influence of climate (mean annual rainfall, rainfall variability, ambient temperature, T
 a) on the basal metabolic rate (BMR) of 267 small mammals (<1 kg) from six zoogeographical zones was investigated using conventional and phylogenetically independent data (linear contrasts). All climate variables varied between zones, as did BMR and body temperature (T
 b) , but not thermal conductance. Holarctic zones were more seasonal and colder, but rainfall was less variable, than non-Holarctic zones. In general, the BMR was most strongly influenced by body mass, followed by T
 a and the rainfall variables. However, there was significant variation in the strength of these relationships between zones. BMR and T
 b increased with latitude, and mass-independent BMR and T
 b were positively correlated. The latter relationship offers evidence of a slow-fast metabolic continuum in small mammals. The fast end of the continuum (high BMR) is associated with the highest latitudes where BMR is most strongly influenced by T
 a and mean annual rainfall (i.e. mean productivity). The slow end of the continuum (low BMR) is associated with the semi-tropics, low productivity zones, and climatically unpredictable zones, such as deserts. Here rainfall variability has the strongest influence on BMR after body size. The implications of a slow–fast metabolic continuum are discussed in terms of various models associated with the evolution of BMR, such as the aerobic capacity models and the "energetic definition of fitness" models.

The influence of climate on the basal metabolic rate of small mammals: a slow-fast metabolic continuum

Cell kinetics and sister-chromatid-exchange frequency in human lymphocytes.

Sister-chromatid exchanges in cigarette-smoking human females and their newborns.

In the present study the cytogenetic effects in hospital workers exposed to low-level radiation were evaluated Samples of peripheral blood were collected from 63 subjects working in radiodiagnostics and from 30 subjects, working in the same hospitals, who were used as controls A higher number of cells with chromosome-type aberrations (CA) was observed in the exposed workers vs the controls and the difference was statistically significant ( p A significant difference was observed in the incidence of cells with CA between smokers and non-smokers, but in the control group only In contrast, in the workers exposed to ionizing radiation, the frequency of cells with CA was very similar in smokers and non-smokers

Cytogenetic monitoring of hospital workers exposed to low-level ionizing radiation

Phylogenetic relationships among the Malagasy lemuriforms (Primates: Strepsirrhini) as indicated by mitochondrial sequence data from the 12S rRNA gene

Cytogenetic tests were performed on operating room personnel working in a Turin hospital. The aim of our study was to determine if any chromosome damage was caused by the use of anaesthetic gases. Blood samples were collected from 45 hospital workers: 15 exposed to anaesthetic gases, 15 exposed to both anaesthetic gases and ionizing radiations and 15 controls. An examination of sister-chromatid exchanges did not highlight significant differences when exposed subjects were compared to controls. Chromosomal aberrations were significantly higher (P = 0.029) in all the exposed personnel, while no statistically significant increase was observed in staff exclusively in contact with anaesthetic gases. Moreover there was a positive correlation for chromosome aberrations with the years of employment, when the entire exposed population was considered and when personnel from the different operating rooms were considered separately. Both sister-chromatid exchange and chromosomal aberrations were higher among smokers though differences were not statistically significant.

G. Ardito

Papers

Cell kinetics and sister-chromatid-exchange frequency in human lymphocytes.

Sister-chromatid exchanges in cigarette-smoking human females and their newborns.

Cytogenetic monitoring of hospital workers exposed to low-level ionizing radiation

Phylogenetic relationships among the Malagasy lemuriforms (Primates: Strepsirrhini) as indicated by mitochondrial sequence data from the 12S rRNA gene

Chromosome analysis in operating room personnel