In vivo cytogenetic studies of the genotoxic effects of polymethyl methacrylate employed in orthopaedics.

Polymethyl methacrylate (PMMA) is a material employed as a cement in prosthesis that has been found to induce cytogenetic damage in human lymphocytes in vitro. This effect is particularly achieved before the 5th day of the exposition, while after this period no significant variations appeared. In the present study, results of cytogenetic tests in humans are reported. Sister chromatid exchange analysis and micronucleus tests have been performed on lymphocytes of patients who had undergone prosthesization with cemented prosthesis (group A) or with biological anchorage prosthesis, as control (group B). DNA damage was investigated before implantation and 5 d after surgery in both groups. Cytogenetic tests did not show any significant increase in the number of micronuclei and sister chromatid exchanges with respect to control values in patients with PMMA cemented prosthesis.

Chromosome aberrations in hospital workers: evidence from surveillance studies in Italy (1963-1993).

Hospital workers are occupationally exposed to various agents known or suspected to induce chromosome damage, the most studied being ionizing radiation. To determine the extent of chromosome damage in peripheral blood lymphocytes in this population, taking into account temporal changes and job titles, a re-analysis of cytogenetic studies performed in four Italian laboratories in the period 1965-1993 was carried out. A total of 871 hospital workers and 617 controls, mainly coming from ad hoc studies or surveillance programs in occupational groups potentially exposed to ionizing radiation, were examined. The exposed to controls frequency ratio of chromosome aberrations was evaluated as the measure of effect within each dataset by job title, using multivariate Poisson regression analysis, which allowed an efficient control of confounding. Increased frequency of chromosome-type aberrations among exposed subjects was found in all datasets, especially in those dealing with older data. Significantly higher frequencies are reported for various job titles, particularly for orthopedists, radiologists, anesthesists, and nurses among paramedical occupations. Decrease in exposure to ionizing radiation in hospital workers was documented through a targeted study in the critical group of radiologists. A similar time-related reduction in the frequency of chromosome-type aberrations also has been reported by the surveillance studies carried out over the most recent decades. These data substantiate the use of chromosome-type aberrations as biomarkers of exposure in this occupational setting in the period evaluated. However, the increases observed also in workers with doubtful exposure to ionizing radiation indicate that other chromosome-damaging agents may be involved and, in turn, suggest the extension of surveillance to a larger number of occupations.

Increased frequencies of sister chromatid exchanges and micronuclei in "in vitro" lymphocyte cultures treated with the fungicides thiram and ziram.

The two fungicides analysed in this paper, Thiram (TH) and Ziram (ZI) are among the most common residues found in fruit and vegetables sold in Italy. These compounds were tested in "in vitro" lymphocyte cultures, from 16 individuals, at different concentrations (Thiram 5 x 10(-8) M; 5 x 10(-7) M; 5 x 10(-6) M and Ziram 1 x 10(-7) M; 1 x 10(-6) M; 1 x 10(-5) M) in order to ascertain if they are able to modify sister chromatid exchange and/or micronuclei frequencies. Both fungicides produced a significant increase in SCE and Micronuclei frequencies. The two highest doses of TH and ZI were found to be cytotoxic for most of the individuals and were not included in the statistical analysis. With regard to the Proliferation Rate Index (i.e. the number of first, second, third or more mitoses), no difference was found between controls and treated cultures.

Cytogenetic effect of thiabendazole and diphenylammine on cultured human lymphocytes: sister chromatid exchanges and cell cycle delay.

The two fungicides analysed in this paper, Thiabendazole (TBZ) and Diphenylammine (DPA), are among the pesticides found in higher concentration in fruits and vegetables sold in Tuscany. These compounds were tested in "in vitro" lymphocyte cultures at different concentrations and using 3 protocols; protocol 1: the cultures were treated with the fungicides for 48 h; protocols 2 and 3: the cultures were treated with fungicides for 4 h in the presence or absence of the metabolic activator S9 mix. Both fungicides produced a slight increase in the SCE frequency in the 48 h treatment, at the higher non-toxic concentrations tested, but not when exposed for only 4 h, with or without S9 mix. As far as concerns the Proliferation Rate Index (i.e. the number of first, second and third mitoses), Thiabendazole also produced a significant decrease in the replication rate of the treated cultures, while Diphenylammine did not produce any effect.

Influence of sex on cytogenetic end points: evidence from a large human sample and review of the literature.

The planning and evaluation of human cytogenetic studies should contemplate various confounders and effect modifiers, among these, sex and sex-related factors. The association between this variable and cytogenetic damage has been extensively studied, but conclusive evidence has thus far not been reached, especially for the most recent assays, such as the micronucleus test (MN). In the attempt to quantitatively estimate the sex effect on sister chromatid exchange (SCE), chromosomal aberration (CA), and MN in peripheral blood lymphocytes, we reanalyzed the original data sets of several biomonitoring studies performed over the last decades in 10 Italian laboratories. This approach yielded a very large database, namely 2140, 2495, and 2131 subjects screened for SCE, CA, and MN, respectively. Differences between sexes were expressed in terms of relative risk (RR) of females versus males, after adjustment for age, smoking habits, occupation exposure and inter- and intralaboratory variation. No difference between sexes was found for the frequency of SCE [RR = 1.01; 95% confidence interval (CI) = 0.99-1.03] and CA (RR = 1.00; 95% CI = 0.92-1.08) even if the CI of the RR for SCE includes the 3% excess in females frequently reported by the literature. Conversely, a 29% overall increase of the MN rate in females was observed in the whole data set (RR = 1.29; 95% CI = 1.20-1.38). Different trends by age of the MN rate are described in the two sexes, focusing on the peak observed in females in the menopausal period and on the subsequent decrease.

Sister-chromatid exchange rates in XX and XY cells of ten chimeric Callithrix jacchus individuals.

In order to ascertain whether or not sister-chromatid exchange (SCE) differs in relation to sex, SCE rates in XX and XY cells from 10 specimens of marmoset (Callithrix jacchus) were examined. The choice of this primate is particularly suitable for three reasons: most individuals have a chimeric constitution, the X chromosome is quite large and the Y chromosome is particularly small. Therefore, the influence of possible differences in their exposure to the external environment can be eliminated. The results obtained did not reveal any significant difference between SCE rates in male and female cells in any of the examined individuals.

Chromosome analysis in operating room personnel.

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.

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

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 less than 0.05). No correlation was, on the contrary, found between CA and years of exposure. 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.

In vitro research on the possibility of chromosomal damage caused by polymethyl methacrylate in orthopaedics. A preliminary report.

There are few experimental studies in the literature concerned with evaluating the toxic effect of polymethyl methacrylate. Because of the number of patients who are now carriers of this substance, it seems important to ascertain whether or not it could cause chromosomal damage. This study reports the preliminary data obtained from an in vitro technique on human lymphocytes placed in contact with different concentrations of methyl methacrylate and its polymerized form. The method consists of an analysis of the exchanges of DNA tracts in the chromosomes of these lymphocytes; the increase in the frequency of exchange as compared to that in the controls is an indication of the mutagenic effect. A slight increase in the average frequency of isochromatid exchanges in the lymphocytes cultivated with the monomer was observed, and this deserves closer study. However, this preliminary data would appear to exclude the existence of chromosomal damage.

Comparison of chromosome aberration frequency before and after administration of 131I in two groups of thyroid cancer patients.

The chromosome aberration frequencies of 10 thyroid cancer patients, before and after their first radioiodine treatment (group A), were compared to the frequencies found in another 10 subjects previously treated with two or more radioiodine administrations (group B). Our data show that the relative increase in chromosome-type aberrations was similar in the two groups: from 2.0% to 3.7% (group A) and from 4.7% to 9.0% (group B). However, the increase in the number of cells with aberrations was greater in group A. Moreover, the higher frequency of aberrations in group B, even before the radioiodine treatment, points out the effect of previous treatments and demonstrates the persistence of this type of lesion. The sister chromatid exchange frequency in the two groups was also analysed, but no effect bound to the radioiodine treatment could be demonstrated.

Influence of a constant magnetic field on human lymphocyte cultures.

The growing exposure to magnetic fields of a certain intensity could represent a serious hazard for our health. In the present note we analyze the effect of a 740 Gauss magnetic field on human lymphocyte cell cultures. From the analysis of our data it is possible to point out that this field produces an inhibition of the cell growth, while does not affect at all the sister chromatid exchange frequency of the chromosomes. Conversely we found a significant increase of chromosome aberrations in the exposed cells. The chromosome aberrations found were mostly gaps and breaks.

The effect of cell kinetics and harvest time on SCE and NOR associations in Macaca fuscata lymphocytes.

The relationship between cell kinetics and cell harvest time on sister chromatid exchange (SCE) and NOR (marker chromosome) association was investigated in cultured Macaca fuscata lymphocytes. The average number of SCE's in individuals ranged from 3.77 to 9.07 per cell. The highest SCE rate was found in cultures harvested at 60 h. The data suggest a decrease in SCE frequency between 60 h and subsequent cell harvest at 72, 84, and 96 h. NOR association frequency was also affected by cell kinetics, as well as by cell harvest time. The highest association frequencies were at 48 h, when the number of first mitoses was greatest.

The banded karyotypes of Macaca fuscata compared with Cercocebus aterrimus.

The karyotypes of Macaca fuscata and Cercocebus aterrimus are compared after G, C and AgNOR banding. Although it is often assumed that the 42-chromosome monkeys (species of the genera Macaca, Papio, and Cercocebus) are identical at the chromosomal level, a number of clear and consistent differences between the karyotypes of these two taxa are described. These differences include one pericentric inversion and differences in staining intensity, particularly in centromeric and pericentromeric areas. It is probable that high resolution chromosome techniques could reveal more differences between taxa in the 42-chromosome group than are now believed to exist. It is therefore probable that karyological data could provide insight into the phylogenetic relationships in this group of Old World monkeys.

[Environmental pollutants and karyologic effects. Usefulness of environmental and biological monitoring]. / Inquinanti ambientali ed effetti cariologici. Utilità del monitoraggio ambientale e biologico.

The results of a study carried out on a group of workers exposed to numerous pollutants (HCl, NaOH, ZnCl2, Sn, Pb, ecc.) in an industrial environment are reported. The research was broken down into two parts: 1) drawing up of a map of environmental pollution; 2) evaluation of the biological exposure of individuals submitted to control. The blood level of Pb was assessed in chosen subjects as a biological indicator of exposure and, at the same time, lymphocyte cultures were prepared in order to highlight any increase in chromosome exchanges and chromosome aberrations.