Developing a microbial consortium for removing nutrients in dishwasher wastewater: towards a biofilter for its up-cycling

Microbial consortia are effective biofilters to treat wastewaters, allowing for resource recovery and water remediation. To reuse and save water in the domestic cycle, we assembled a suspended biofilm, a 'biofilter' to treat dishwasher wastewater. Bacterial monocultures of both photo- and heterotrophs were assembled in an increasingly complex fashion to test their nutrient stripping capacity. This 'biofilter' is the core of an integrated system (Zero Mile System) devoted to reusing and upcycling of reconditioned wastewater, partly in subsequent dishwasher cycles and partly into a vertical garden for plant food cultivation. The biofilter was assembled based on a strain of the photosynthetic, filamentous cyanobacterium Trichormus variabilis, selected to produce an oxygen evolving scaffold, and three heterotrophic aerobic bacterial isolates coming from the dishwasher wastewater itself: Acinetobacter, Exiguobacterium and Pseudomonas spp. The consortium was constructed starting with 16 isolates tested one-to-one with T. variabilis and then selecting the heterotrophic microbes up to a final one-to-three consortium, which included two dominant and a rare component of the wastewater community. This consortium thrives in the wastewater much better than T. variabilis alone, efficiently stripping N and P in short time, a pivotal step for the reuse and saving of water in household appliances.

Parchment processing and analysis: Ionizing radiation treatment by the REX source and multidisciplinary approach characterization

Library material, and thus parchment, is frequently subjected to bio-deterioration processes caused by microorganisms. Fungi and bacteria cause alterations in the parchment inducing, in some cases, even the partial detachments of the surface layer and the loss of any text present on it. An important contribution to disinfection of the cultural heritage artefacts is given by the use of ionizing radiation. In this work, a preliminary study on the applicability of X-ray radiation as treatment for bio-deterioration removal is proposed. The results on the microbial growth after different irradiation treatments are shown in order to detect the dose protocol for the bio-degradation removal. Furthermore, the evaluation of the irradiation effects on the parchment microstructure is presented in order to define the applicability of the method on parchment artefacts.

DNA methylation of genes regulating appetite and prediction of weight loss after bariatric surgery in obese individuals

PURPOSE

Epigenetic traits are influenced by clinical variables; interaction between DNA methylation (DNAmeth) and bariatric surgery-induced weight loss has been scarcely explored. We investigated whether DNAmeth of genes encoding for molecules/hormones regulating appetite, food intake or obesity could predict successful weight outcome following Roux-en-Y gastric bypass (RYGB).

METHODS

Forty-five obese individuals with no known comorbidities were stratified accordingly to weight decrease one-year after RYGB (excess weight loss, EWL ≥ 50%: good responders, GR; EWL < 50%: worse responders, WR). DNAmeth of leptin (LEP), ghrelin (GHRL), ghrelin receptor (GHSR) and insulin-growth factor-2 (IGF2) was assessed before intervention. Single nucleotide polymorphisms of genes affecting DNAmeth, DNMT3A and DNMT3B, were also determined.

RESULTS

At baseline, type 2 diabetes was diagnosed by OGTT in 13 patients. Post-operatively, GR (n = 23) and WR (n = 22) achieved an EWL of 67.7 ± 9.6 vs 38.2 ± 9.0%, respectively. Baseline DNAmeth did not differ between GR and WR for any tested genes, even when the analysis was restricted to subjects with no diabetes. A relationship between GHRL and LEP methylation profiles emerged (r = 0.47, p = 0.001). Searching for correlation between DNAmeth of the studied genes with demographic characteristics and baseline biochemical parameters of the studied population, we observed a correlation between IGF2 methylation and folate (r = 0.44, p = 0.003). Rs11683424 for DNMT3A and rs2424913 for DNMT3B did not correlate with DNAmeth of the studied genes.

CONCLUSIONS

In severely obese subjects, the degree of DNAmeth of some genes affecting obesity and related conditions does not work as predictor of successful response to RYGB.

Pregnancy risk factors related to autism: an Italian case-control study in mothers of children with autism spectrum disorders (ASD), their siblings and of typically developing children

This study, carried out in two Italian Institutions, assesses the frequency of 27 potential autism risk factors related to pregnancy and peri- and postnatal periods by interviewing mothers who had children with autism, children with autism and one or two typically developing siblings, or only typically developing children. The clinical sample included three case groups: 73 children and adolescents with autism (Group A), 35 children and adolescents with autism (Group A1) having 45 siblings (Group B) and 96 typically developing children (Group C) matched for gender and age. Twenty-five out of 27 of risk factors presented a higher frequency in Group A in comparison with Group C and for nine of them a statistically significant difference was found. Twenty-one out of 27 of risk factors presented a higher frequency in Group A in comparison with Group B. A higher prevalence of environmental risk factors was observed in 11 risk factors in the Group A1 in comparison with Group B and for nine of them an odds ratio higher than 1.5 was found. For 13 factors there was a progressive increase in frequency going from Group C, B and A and a statistically higher prevalence of the mean number of stressful events per pregnancy was recorded in Group A when compared with Groups B and C. The results suggest that environmental, incidental phenomena and stressful life events can influence pregnancy outcome in predisposed subjects, pointing out a possible threshold effect in women who are predisposed to have suboptimal pregnancies.

Insights into the CuO nanoparticle ecotoxicity with suitable marine model species

Metal oxide nanoparticles, among them copper oxide nanoparticles (CuO NPs), are widely used in different applications (e.g. batteries, gas sensors, superconductors, plastics and metallic coatings), increasing their potential release in the environment. In aquatic matrix, the behavior of CuO NPs may strongly change, depending on their surface charge and some physical-chemical characteristics of the medium (e.g. ionic strength, salinity, pH and natural organic matter content). Ecotoxicity of CuO NPs to aquatic organisms was mainly studied on freshwater species, few tests being performed on marine biota. The aim of this study was to assess the toxicity of CuO NPs on suitable indicator species, belonging to the ecologically relevant level of consumers. The selected bioassays use reference protocols to identify Effect/Lethal Concentrations (E(L)C), by assessing lethal and sub-lethal endpoints. Mortality tests were performed on rotifer (Brachionus plicatilis), shrimp (Artemia franciscana) and copepod (Tigriopus fulvus). While moult release failure and fertilization rate were studied, as sub-lethal endpoints, on T. fulvus and sea urchin (Paracentrotus lividus), respectively. The size distribution and sedimentation rates of CuO NPs, together with the copper dissolution, were also analyzed in the exposure media. The CuO NP ecotoxicity assessment showed a concentration-dependent response for all species, indicating similar mortality for B. plicatilis (48hLC₅₀ = 16.94 ± 2.68mg/l) and T. fulvus (96hLC₅₀ = 12.35 ± 0.48mg/l), followed by A. franciscana (48hLC₅₀ = 64.55 ± 3.54mg/l). Comparable EC₅₀ values were also obtained for the sub-lethal endpoints in P. lividus (EC₅₀ = 2.28 ± 0.06mg/l) and T. fulvus (EC₅₀ = 2.38 ± 0.20mg/l). Copper salts showed higher toxicity than CuO NPs for all species, with common sensitivity trend as follows: P. lividus ≥ T. fulvus (sublethal endpoint) ≥ B. plicatilis >T. fulvus (lethal endpoint) >A. franciscana. CuO NP micrometric aggregates and high sedimentation rates were observed in the exposure media, with different particle size distributions depending on the medium. The copper dissolution was about 0.16% of the initial concentration, comparable to literature values. The integrated ecotoxicological-physicochemical approach was used to better describe CuO NP toxicity and behavior. In particular, the successful application of ecotoxicological reference protocols allowed to produce reliable L(E)C data useful to identify thresholds and assess potential environmental hazard due to NPs.

Can Artemia Hatching Assay Be a (Sensitive) Alternative Tool to Acute Toxicity Test?

Artemia sp. is extensively used in ecotoxicity testing, despite criticisms inherent to both acute and long-term tests. Alternative endpoints and procedures should be considered to support the use of this biological model. The hatching process comprises several developmental steps and the cyst hatchability seems acceptable as endpoint criterion. In this study, we assessed the reliability of the hatching assay on A. franciscana by comparing with acute and long-term mortality tests, using two chemicals: Diethylene Glycol (DEG), Sodium Dodecyl Sulphate (SDS). Both DEG and SDS tests demonstrated a dose dependent hatching inhibition. The hatching test resulted more sensitive than acute mortality test and less sensitive than the long-term one. Results demonstrate the reliability and high sensitivity of this hatching assay on a short time lag and support its useful application in first-tier risk assessment procedures.

Therapeutic perspectives of epigenetically active nutrients

Many nutrients are known for a wide range of activities in prevention and alleviation of various diseases. Recently, their potential role in regulating human health through effects on epigenetics has become evident, although specific mechanisms are still unclear. Thus, nutriepigenetics/nutriepigenomics has emerged as a new and promising field in current epigenetics research in the past few years. In particular, polyphenols, as part of the central dynamic interaction between the genome and the environment with specificity at physiological concentrations, are well known to affect mechanisms underlying human health. This review summarizes the effects of dietary compounds on epigenetic mechanisms in the regulation of gene expression including expression of enzymes and other molecules responsible for drug absorption, distribution, metabolism and excretion in cancer, metabolic syndrome, neurodegenerative disorders and hormonal dysfunction.

Epigenetics of colorectal cancer

Colorectal cancer (CRC) develops through a multistep process that results from the progressive accumulation of mutations and epigenetic alterations in tumor suppressor genes and oncogenes. Epigenetic modifications, that have a fundamental role in the regulation of gene expression, involve DNA methylation, specific histone modifications and non-coding RNAs (ncRNAs) interventions. Many genes have been until now studied to detect their methylation status during CRC carcinogenesis; and the functions of many of these genes in cancer initiation and progression are being clarified. Less is known about the patterns of histone modification alterations in CRC. Epigenetic deregulation of the ncRNAs or the genes involved in their biogenesis have been described in tumor progression and some examples of dysregulated microRNA were found also in CRC cells. Diet has an important role in the etiology of colon cancer. Folate is involved via 5-methyltetrahydrofolate in the conversion of homocysteine to methionine, which is then used to form the main DNA methylating agent S-adenosylmethionine. However, the role of folate in protecting from or in promoting CRC, depending on conditions, is still debated. The study of epigenetic marks to better characterize CRC and to identify new tools for diagnosis and prognosis as well as for therapeutic interventions is extremely promising.

Fungal bioremediation of creosote-treated wood: a laboratory scale study on creosote components degradation by Pleurotus ostreatus mycelium

A bioremediation system for creosote-treated wood is proposed, based on the detoxifying capability of Pleurotus ostreatus, a ligninolythic fungus. Non-sterilized chipped contaminated wood was mixed at various ratios with wheat straw on which Pleurotus mycelia was grown. At 1:2 initial ratio contaminated wood:wheat straw, chemical analyses demonstrated an almost complete degradation of creosote oil components after 44 days, also confirmed by a significant reduction of ecotoxicity. Lower ratios, i.e. higher amount of contaminated wood, lower system efficiency, although a better creosote degradation was obtained by a stepped up wood addition.

Genotoxicity induced by arsenic compounds in peripheral human lymphocytes analysed by cytokinesis-block micronucleus assay

This work focuses on the analysis of genotoxic effects on human peripheral lymphocytes exposed in vitro to different arsenic (As) compounds by means of the cytokinesis-block micronucleus assay. The study was carried out by challenging peripheral human lymphocytes with six As compounds in trivalent or pentavalent forms such as arsenite (As(III)) and arsenate (As(V)) and organoarsenic species such as monomethylarsonous acid (MMAs(III)), monomethylarsonic acid (MMAs(V)), dimethylarsinic acid (DMAs(V)) and trymethylarsine oxide (TMAO(V)). For As(III) and As(V) at concentrations of 4 and 32 microM, respectively, an increase of micronuclei (MN) frequency was found. MMAs(III) and MMAs(V) induced a statistically significant increase of MN frequency at the dose of 2 and 500 microM, respectively. For DMAs(V), no significant increase of MN was observed, although a decrease of the nuclear division index (NDI) was evident, indicating a cytotoxic effect. The genotoxic mechanism of action of MMAs(III) was further evaluated by means of fluorescence in situ hybridization analysis. Due to a higher percentage of centromere-positive MN, MMAs(III) showed a clear aneuploidogenic property. Finally, for TMAO(V) no genotoxicity was observed up to 1 mM. These results show how speciation is important in determining the genotoxic and cytotoxic effects of As compounds in human peripheral lymphocytes and support the emerging hypothesis that the induction of aneuploidy could be a mechanism by which As exerts its carcinogenic properties.

Nanomaterials and lung toxicity: interactions with airways cells and relevance for occupational health risk assessment

Engineered nanoparticles (NP) comprise various classes of technological materials with innovative properties. Although inhalation is less likely for engineered nanomaterials (NM) compared with ambient or mineral dust particles, this can happen during bulk manufacture and handling of freely dispersible NP. In this mini-review we summarize recent data on NP and CNT (carbon nanotubes) hazards, with particular emphasis on toxic effect on lung and in cell culture of lung origin. Owing to the highest deposition efficiency in the alveolar area, primary interactions of NM occur with epithelial and alveolar macrophages (AM). Scarce data are available to date on the cell mechanisms underlying NM permeability across the airway epithelium, but the absorption of NP through airways does not seem to require epithelial mediation, suggesting rather the involvement of alternative mechanisms such as AM-dependent dissemination. The relationship between toxicity and particle characteristics may be complex, involving size, surface area and surface chemistry. Some NM act according to an oxidative stress paradigm, but possible NM interactions with biological systems may result in additional forms of injury. In particular, CNT, a man-made forms of crystalline carbon, are currently attracting intense research efforts because of their unique properties, which make them suitable for many uses in biomedicine and pharmacology. Although CNT stimulate cytokine production and induce inflammatory reactions, they could behave also as conventional fibers, showing the ability to cause lung granulomas and fibrotic reactions in experimental animals. Production and marketing of NM is advancing much more rapidly than research on NM safety. This phenomenon will have a strong impact on the approach of occupational physicians to health risks from NP. In literature increasing evidence suggests that NM are potentially hazardous to humans and that strict industrial hygiene measures should be taken to limit exposure during their manipulation. Moreover, given the uncertainty about the NM features endowed with pathogenetic relevance, the toxicological properties of a specific NP should be evaluated on an individual basis by new screening strategies based on current acquisitions.

An in vitro study on the free radical scavenging capacity of ergothioneine: comparison with reduced glutathione, uric acid and trolox

BACKGROUND

Treatment of oxidative stress-related pathologies is a possible therapeutical strategy for the future. Natural product with antioxidant properties could trigger this goal. The aim of this in vitro study was to assess the antioxidant activity of the natural product ergothioneine (EGT), a compound of plant origin, which is assimilated and conserved by mammals in erythrocytes, kidney, seminal fluid and liver.

METHODS

We measured the antioxidant activity of EGT as its ability to antagonize the oxidation of alpha-keto-gamma-methiolbutyric acid (KMBA) by hydroxyl radical, peroxyl radicals and peroxynitrite. The results are expressed as total oxyradical scavenging capacity (TOSC) units. Glutathione (GSH), uric acid and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (trolox), the water-soluble analog of vitamin E, were used as the reference antioxidants.

RESULTS

EGT was the most active scavenger of free radicals as compared to classic antioxidants as GSH, uric acid and trolox. In particular, the highest antioxidant capacity exhibited by EGT vs. peroxyl radicals (5.53 +/- 1.27 units) resulted 25% higher than the value obtained with the reference antioxidant trolox (4.4 +/- 0.6 units, P < 0.01). The scavenging capacity of EGT towards hydroxyl radicals (0.34 +/- 0.09 units) was 60% higher, as compared to uric acid (0.21 +/- 0.04 units, P < 0.001), which represent the reference antioxidant vs. hydroxyl radicals. Finally, EGT showed the highest antioxidant activity also towards peroxynitrite (5.2 +/- 1.0 units), with a scavenging capacity 10% higher than that of uric acid (4.7 +/- 0.9 units, P < 0.05).

CONCLUSIONS

This study showed that EGT has potent intrinsic anti-hydroxyl, anti-peroxyl and anti-peroxynitrite radicals antioxidant activity, as compared to classic molecules with antioxidant capacity as GSH, trolox and uric acid. This appears of interest, given the increasing use of non-vitamins cocktails for therapeutical approaches to many oxidative-induced pathologies.

Relationship between genotoxicity biomarkers in somatic and germ cells: findings from a biomonitoring study

A biomonitoring study to evaluate chromosome and DNA damage respectively in somatic and germ cells of a group of male workers exposed to styrene by using biomarkers of genotoxicity was carried out. Styrene-exposed workers from three different areas of Tuscany and healthy subjects, of comparable mean age, sex and lifestyle characteristics, as a control group not exposed to chemicals, have been enrolled. In addition to previous reports [L. Migliore, A. Naccarati, A. Zanello, R. Scarpato, L. Bramanti and M. Mariani (2002) Hum. Reprod., 17, 2912-2918; L. Migliore, A. Naccarati, F. Coppedè et al. (2006) Pharmacogenet. Genomics, 16, 87-99] we present now data on a cross-sectional investigation involving a homogeneous group of subjects for which data on both somatic and germ cells have been obtained from individuals (42 exposed and 25 controls). Somatic cell genotoxicity was assessed by analysing the frequency of micronucleated binucleated cells (MNBN) in blood lymphocytes. The micronucleus assay was coupled with centromeric fluorescence in situ hybridization (FISH) analysis. Primary DNA damage in germ cells was evaluated by alkaline single-cell gel electrophoresis (Comet assay) and the percentage of the tail DNA (%TD) was used as parameter of Comet evaluation. Moreover, to investigate the frequencies of aneuploidy and diploidy in sperm, we performed multicolour FISH, using DNA probes specific for the centromeric regions of sex chromosomes and chromosome 2, in decondensed sperm nuclei of samples with normal semen parameters in a subgroup of individuals. Mandelic and phenylglyoxylic acids (MAPGA) in end of shift samples were determined as biomarkers of internal dose. MAPGA excretion was consistent with an exposure to styrene above the threshold limit value-time weighted average concentration of 20 p.p.m. Styrene workers showed significantly higher frequency of MNBN as compared to controls (13.8 +/- 5.2 versus 6.2 +/- 5.1; P < 0.001), due to higher proportions of both micronuclei (MN) arising from chromosomal breakage (C-MN) and harbouring whole chromosomes (C+MN). DNA damage in sperm cells was also higher among styrene-exposed, the %TD being 11.02 +/- 2.99 versus 7.42 +/- 2.30 in controls (P < 0.001). The incidence of aneuploidy and diploidy for the tested chromosomes in sperm did not show a statistically significant difference between workers and controls. However, a positive correlation was found between genotoxic damage detected in somatic and in germ cells, even after removing the effect of age (r = 0.475; P < 0.001). Although cytogenetic biomarkers detected both in somatic and germ cells were interrelated, no relationships were apparent with exposure parameters. Styrene exposure may increase the likelihood of both chromosome and DNA damage in somatic and germ cells, thus supporting the hypothesis of an interference on reproductive capacity among exposed workers. This is the first time that a field study shows a correlation between two biomarkers of genotoxicity evaluated at the same time in somatic and germ cells.

Susceptibility to chromosome malsegregation in lymphocytes of women who had a Down syndrome child in young age

Recent findings seem to converge towards a unified hypothesis trying to relate Down's syndrome (DS), trisomy 21 and Alzheimer's disease (AD). The majority of DS individuals develop neuropathological characteristics of AD by the age of 40. Previous cytogenetic studies performed by us showed an increased frequency of aneuploidy in peripheral lymphocytes and fibroblasts of AD patients and a preferential occurrence of chromosome 21 in malsegregation events. An increased frequency of AD among young mothers of individuals with DS (MDS) is reported. This study investigates the cytogenetic characteristics and the predisposition to chromosome malsegregation of peripheral blood lymphocytes in a group of women (n = 35) who had a Down syndrome child in young age (<35 years) and in a control group (n = 30). We applied the micronucleus assay and the dual-color FISH in order to assess the susceptibility to malsegregation events. The results indicate a higher frequency of binucleated micronucleated cells in MDS in respect to the control group (16.1+/-9.1 per thousand versus 8.7+/-5.4 per thousand). Moreover, our data reveal that peripheral lymphocytes of MDS are more prone to chromosome non-disjunction with both chromosomes, 13 and 21, equally involved.

Oxidative DNA damage in peripheral leukocytes of mild cognitive impairment and AD patients

It is well established that oxidative stress plays a key role in the degenerative neuronal death and progression of Alzheimer's disease (AD), although it is not clear if it is the primary triggering event in the pathogenesis of this disorder. Mild cognitive impairment (MCI) is a clinical condition between normal aging and AD, characterized by a memory deficit without loss of general cognitive and functional abilities. We performed this study by a comet assay analysis to evaluate the level of primary and oxidative DNA damage in two groups of MCI and AD patients, compared to healthy controls. Data showed a significantly higher level of primary DNA damage in leukocytes of AD and also of MCI patients compared to control individuals (average: 2.09+/-0.79 and 2.47+/-1.01, respectively for AD and MCI, versus 1.04+/-0.31 in controls). Moreover, the amount of oxidised DNA bases (both purines and pyrimidines) was significatively higher in the two groups of patients (AD and MCI) compared to controls. Our results give a further indication that oxidative stress, at least at the DNA level, is an earlier event in the pathogenesis of AD.

Searching for the role and the most suitable biomarkers of oxidative stress in Alzheimer's disease and in other neurodegenerative diseases

The contribution of oxidative stress to neurodegeneration is not peculiar of a specific neurodegenerative disease, oxidative stress has been found implicated in a number of neurodegenerative disorders among which Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS). Even increasing are studies dealing with the search for peripheral biomarkers of oxidative stress in biological fluids or even in peripheral tissues themselves such as fibroblasts or blood cells. The application of the modified version of the comet assay for the detection of oxidised purines and pyrimidines in peripheral blood leukocytes results particularly useful if the study requires repeated blood drawn from the same individual, for instance if a clinical trial is performed with a preventive therapy. Likely damage occurs to every category of biological macromolecules and we consider, in the context of neurodegenerative diseases, particularly critical the proteic level. The identification of subjects at risk to develop AD or with pre-pathogenic conditions, the possibility to use "a battery of assays" for the detection of oxidative damage at peripheral level, together with recent advances in brain imaging, will allow to better address studies aimed not only to therapeutic purposes but also mainly to primary prevention.

Evaluation of cytogenetic and DNA damage in mitochondrial disease patients: effects of coenzyme Q10 therapy

Endogenous oxidative stress is believed to play a key role in the pathogenesis of mitochondrial diseases (MD). In this group of heterogeneous disorders the increased production of radical species caused by compromised mitochondrial respiratory function could affect both mitochondrial and nuclear DNA integrity. The aim of the present study was to assess the basal level of nuclear DNA (nDNA) damage in terms of chromosome and DNA alterations in leukocytes of 13 patients (age range 29-74 years) presenting several forms of MD. A further objective of this work was the evaluation of possible changes in nDNA in a subgroup of patients (10 individuals) before and after a 2 week therapy with ubidecarenone, a coenzyme Q10 analogue. The extent of cytogenetic damage, expressed as chromosome breakage and chromosome loss, was assessed employing the cytokinesis block micronucleus method in cultured peripheral blood lymphocytes, coupled with fluorescence in situ hybridization analysis using a digoxigenin-labelled pancentromeric DNA probe. A modified version of the single cell gel electrophoresis assay was used to quantify primary and oxidative DNA damage in leukocytes. In MD patients an increased level of chromosome damage, expressed as frequency of micronucleated lymphocytes, was detected in comparison with healthy individuals of corresponding sex, age and lifestyle. The FISH analysis revealed a preferential occurrence of micronuclei arising from loss of whole chromosomes in patients, with no substantial difference in frequencies observed in matched controls. The Comet assay indicated a slightly higher level of primary DNA damage in patients compared with controls and also a difference in oxidative DNA damage, however, this was not statistically significant. Patients receiving ubidecarenone showed a statistically significant reduction in the frequency of micronucleated cells after therapy, while only a slight decrease was observed in the levels of both primary DNA damage and oxidized bases.

[Genetic polymorphism of biotransforming enzymes and genotoxic effects of styrenes]

A cross-sectional study was carried out on laminators producing glass-fibre reinforced plastics, to evaluate the role of genetic polymorphism of xenobiotic metabolising enzymes on the genotoxicity of styrene. Clastogenic effects, evaluated by the micronucleus test, are related with end-of-shift urinary concentration of 4-vinylphenol and seem to be modulated by NQO1 polymorphism; aneuploidogenic effects, evaluated by the identification of centromers in micronuclei using the fluorescence in situ hybridisation technique with a pancentromeric probe, are related with before-shift urinary levels of mandelic and phenylglyoxylic acids and seem to be modulated by the GSTM1 polymorphism.

[Chromosome aberrations, valued as frequency of spontaneous micronuclei, in subjects with suspected presclerodermic Raynaud's phenomenon]

OBJECTIVE

To evaluate the prevalence of spontaneous chromosome damage in cultured peripheral lymphocytes of subjects with suspected presclerodermic Raynaud's phenomenon (RP), by means of molecular cytogenetic analysis.

METHODS

We studied 20 suspected presclerodermic RP, 20 idiopathic RP and 25 healthy subjects. As marker of chromosome alteration we used the micronucleus assay. All subjects were also classified as ANA-, ACA+ or Scl70+. To identify the mechanism of MN formation, a MN fluorescence in situ hybridisation (FISH) analysis using a pancentromeric DNA probe was also performed.

RESULTS

Suspected presclerodermic RP subjects, showed significantly higher MN frequencies than idiopathic RP and controls (39+/-15.2 vs 10+/-2.1 and 9.8+/-3.5 respectively p<0.0001). Interestingly, subjects with idiopathic RP displayed MN frequency comparable to that of controls. Furthermore, ACA+ subjects showed the highest MN frequencies (44+/-8.1) as compared to subjects with different antibody pattern (26+/-7.1).

CONCLUSIONS

Our results show the presence of higher levels of chromosomal damage in circulating lymphocytes of suspected presclerodermic RP. They also would suggest a key role of anti-centromere antibody in determining the observed cytogenetic anomalies. FISH analysis indicated that both aneuploidogenic and clastogenic events contribute to the formation of MN observed in suspected presclerodermic RP.

Cytogenetic alterations in lymphocytes of Alzheimer's disease and Parkinson's disease patients

We investigated the presence of cytogenetic alterations in peripheral blood lymphocytes of Alzheimer's disease (AD) and Parkinson's disease (PD) patients. Detection of spontaneous structural and/or numerical chromosome damage has been assessed by micronucleus (MN) assay coupled with fluorescence in situ hybridization (FISH). The cytogenetic investigation was performed on 22 AD patients, 18 PD patients, and 20 controls. The spontaneous frequencies of micronuclei (MN) in human lymphocytes of both AD and PD patients were significantly higher than in controls. The majority of MN was composed of whole chromosomes in AD patients, while a prevalence of MN arising from chromosome breakage was observed in PD patients. Different molecular mechanisms underlie cytogenetic alterations observed in peripheral lymphocytes of AD and PD patients.

[The high frequency of spontaneous micronuclei observed in lymphocytes of systemic sclerosis patients: preliminary results]

OBJECTIVE

Aim of the study is to assess the presence of spontaneous chromosome damage in patients affected by limited (lSSc) or diffuse (dSSc) Systemic Slerosis, using the micronucleus (MN) assay.

METHODS

We evaluated MN frequency in cultured peripheral lymphocytes of 18 SSc and in a group of 20 healthy controls. Patients were also classified as ACA+, Scl70+, FAN+ according to the presence of the specific anti-nuclear antibodies. We also explored the hypothesis that the extent of cytogenetic alteration might be related to the severity of the pathological condition and/or to the immunological profile.

RESULTS

Compared to controls, the patient group as a whole showed significantly higher MN frequencies (10.8+/-4.5 vs. 27.8+/-13.7, p<0.001). No correlation was found between spontaneous chromosome damage and severity of the disease, being MN frequency 33.1+/-17.0 and 19.8+/-2.7 in lSSc and dSSc, respectively. Interestingly, ACA+ subjects displayed the highest MN frequency (36.9+/-15.0), as compared to patients with different antibody pattern (Scl70+, FAN+; 19.7+/-8.2).

CONCLUSIONS

Our results confirm the presence of chromosomal damage in circulating lymphocytes of SSc patients and would suggest a key role of antibodies to the centromere in determining the observed cytogenetic anomalies.

Oxidative damage and cytogenetic analysis in leukocytes of Parkinson's disease patients

BACKGROUND

Postmortem studies suggest excessive free radical toxicity in the substantia nigra of patients with PD. Increased lipid peroxidation and oxidative DNA damage have been reported in the CNS. Markers of oxidative stress have been identified in the blood of patients with PD.

OBJECTIVE

To assess the presence of spontaneous chromosome and primary or oxidative DNA damage in peripheral blood leukocytes of patients with untreated PD.

METHODS

Patients with de novo PD (20) and control subjects (16), matched for age, sex, and smoking habits, underwent cytogenetic analysis using the human lymphocyte micronucleus assay coupled with the fluorescence in situ hybridization technique and the Comet assay.

RESULTS

Compared with controls, patients with PD showed an increase in the incidence of spontaneous micronuclei (p < 0.001); single strand breaks (p < 0.001); and oxidized purine bases (p < 0.05). Fluorescence in situ hybridization analysis showed micronuclei harboring acentric fragments.

CONCLUSIONS

There is chromosomal, primary DNA damage and oxidative DNA damage demonstrable in lymphocytes of patients with untreated PD.

Cytogenetic damage in peripheral lymphocytes of mitochondrial disease patients

Recent studies indicate an important role of endogenous oxidative stress in the onset and/or in the progression of mitochondrial encephalomyopathies. In particular, the increased production of radical species caused by altered mitochondrial functionality could affect both mitochondrial and nuclear DNA integrity. We performed the micronucleus assay coupled with fluorescence in situ hybridization (FISH) to detect chromosome damage in peripheral blood lymphocytes in a group of patients affected by different forms of mitochondrial encephalomyopathies. Moreover the comet assay has been carried out to detect primary and oxidative damage in the nuclear DNA. Our results show a significant presence of both DNA and chromosome damage in patients compared to a matched group of controls. A reduction in DNA alterations is also observed in patients after treatment with coenzyme-Q10.

Chromosome and oxidative damage biomarkers in lymphocytes of Parkinson's disease patients

As cancer development usually results from exposure to several environmental risk factors in interaction with the genetic susceptibility of the host, it could be of interest to investigate if neurodegeneration, as occurs in Parkinson's disease (PD) patients can be attributed at least partially, to environmental risk factors. There is growing evidence that oxidative stress could play a significant role as a risk factor in the aetiology and pathogenesis of neurodegenerative diseases, emphasising the need for new individual and human-based approaches. The aim of our research is to explore the relation between chromosome instability and oxidative stress biomarkers in Parkinson's disease using a variety of strategies. We determined peripheral markers for oxidative damage in PD by testing for spontaneous and induced chromosomal damage, DNA strand breaks, oxidised pyrimidines and altered purines both in peripheral blood and cultured lymphocytes. We also measured glutathione S-transferase activity in the plasma of patients and controls. Compared to healthy controls, PD patients show higher frequencies of micronuclei (17.2 +/- 4.8 vs. 9.0 +/- 3.4, p < 0.001) and a significant increase in the levels of single strand breaks (SSB). Significant differences were also obtained in the distribution of oxidised purine bases between the two groups. Preliminary data obtained by fluorescence in situ hybridization analysis showed that the percentage of centromere negative micronuclei is higher than that of centromere positive micronuclei. Glutathione S-transferase activity in plasma from PD patients and controls was also measured and the enzymatic activity in PD patients was lower than in healthy controls.

Spontaneous and induced chromosome damage in somatic cells of sporadic and familial Alzheimer's disease patients

Alzheimer's disease (AD) is a neurodegenerative disorder of the elderly with a complex etiology due to the interaction between genetic and environmental factors. At least 15% of cases are inherited as an autosomal dominant mutation, but the majority are sporadic. We evaluated cytogenetic alterations, both spontaneous and chemical-induced [aluminium (Al) and griseofulvin (GF)], by means of the micronucleus (MN) test in lymphocytes or skin fibroblasts of 14 patients with sporadic and eight with familial Alzheimer's disease (FAD), respectively. The spontaneous MN frequencies of sporadic (20.8 +/- 9.2) and familial (20.7 +/- 4.6) AD patients are significantly higher than those of the respective control groups (9.0 +/- 6.8 and 6.7 +/- 3.4). In all AD patients, GF significantly increased the spontaneous MN frequency of somatic cells to a lesser extent (P < 0.05) as compared with the control group. Al treatment did not induce MN in AD patients. The results of the present study indicate that different types of somatic cells from sporadic and familial AD patients show comparable levels of spontaneous cytogenetic anomalies, and MN induction is partially reduced or lacking according to the type of chemical treatments.

Cytogenetic analysis oxidative damage in lymphocytes of Parkinson's disease patients

Several lines of evidence support the presence of DNA damage in somatic cells of Parkinson's disease (PD) patients due to the formation of free radical species. In order to detect spontaneous chromosome and primary or oxidative DNA damage, we performed the human lymphocyte micronucleus assay (HLMNA) and comet assay in 19 PD patients and 16 healthy controls. Compared with controls, PD patients showed a significant increase in: (I) spontaneous micronucleus (MN) frequency (p<0.001); (2) single strand break (SSB) levels (p<0.001); and (3) oxidized purine base levels (p<0.05). The chromosome damage and the increased levels of oxidized purine bases observed in our patients support the hypothesis of oxidative stress as a relevant factor in the pathogenesis of PD.

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

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.

Induction of micronuclei in human lymphocytes exposed in vitro to microwave radiation

Increasing applications of electromagnetic fields are of great concern with regard to public health. Several in vitro studies have been conducted to detect effects of microwave exposure on the genetic material leading to negative or questionable results. The micronucleus (MN) assay which is proved to be a useful tool for the detection of radiation exposure-induced cytogenetic damage was used in the present study to investigate the genotoxic effect of microwaves in human peripheral blood lymphocytes in vitro exposed in G(0) to electromagnetic fields with different frequencies (2.45 and 7.7GHz) and power density (10, 20 and 30mW/cm(2)) for three times (15, 30 and 60min). The results showed for both radiation frequencies an induction of micronuclei as compared to the control cultures at a power density of 30mW/cm(2) and after an exposure of 30 and 60min. Our study would indicate that microwaves are able to cause cytogenetic damage in human lymphocytes mainly for both high power density and long exposure time.

Preferential occurrence of chromosome 21 malsegregation in peripheral blood lymphocytes of Alzheimer disease patients

To further investigate our finding of high levels of spontaneous aneuploidy in somatic cells of Alzheimer's disease (AD) patients (Migliore et al. 1997), we studied the molecular cytogenetics of eight patients with sporadic AD and six healthy controls of similar age. Cytochalasin B-blocked binucleated peripheral blood lymphocytes from the AD patients and unaffected controls were used to measure micronucleus induction or other aneuploidy events, such as the presence of malsegregation in interphase nuclei (representing chromosome loss and gain). Dual-color fluorescence in situ hybridization (FISH) with differential labeled DNA probes was applied. We used a probe specific for the centromeres of chromosomes 13 and 21 combined with a single cosmid for the Down's syndrome region (21q22.2) to obtain information on spontaneous chromosome loss and gain frequencies for both chromosomes (13 and 21). FISH data showed that AD lymphocytes had higher frequencies of chromosome loss (evaluated as fluorescently labeled micronuclei) for both chromosomes, as well as higher frequencies of aneuploid interphase nuclei, again involving both chromosomes, compared to control lymphocytes. However, aneuploidy for chromosome 21 was more frequent than for chromosome 13 in AD patients. This preferential occurrence of chromosome 21 in malsegregation in somatic cells of AD patients raises the hypothesis that mosaicism for trisomy of chromosome 21 could underlie the dementia phenotype in AD patients, as well as in elderly Down's syndrome patients.

Phytotoxicity to and uptake of flumequine used in intensive aquaculture on the aquatic weed, Lythrum salicaria L

Phytotoxicity of Flumequine on the aquatic weed Lythrum salicaria L. was determined by two laboratory models: a single concentration test, by which the effects of 100 mg l-1 were evaluated after 10, 20, 30 days and a multiple concentration test, by which the effects of 5000-1000-500-100-50 micrograms l-1 were evaluated after 35-day exposure. 100 mg l-1 are highly toxic and significantly decrease the growth of plants; this effect increases with time. Concentrations between 5000 and 50 micrograms l-1 induced hormesis in plants, by significantly increasing mean number and dimension of leaves and secondary roots. The effect is the highest at 50 micrograms l-1 and decreases with increase in concentration. Both toxic effect and hormesis can be related to plant drug uptake, quite high, in the order of micrograms g-1. The ecological implication of Flumequine contamination in aquatic environments and the possible use of Lythrum salicaria for bioremediation and/or monitoring technique are discussed.

Cytokinesis-block micronucleus assay in primary human liver fibroblasts exposed to griseofulvin and mitomycin C

Primary liver fibroblasts were applied in a cytokinesis-block micronucleus assay in combination with fluorescence in situ hybridization (FISH) using two protocols. In protocol A (Prot. A), cytochalasin B (Cyt B) was added at the end of the treatment time directly to the medium containing the standard compounds, whereas in protocol B (Prot. B) the chemical-containing medium was removed and fresh medium with Cyt B was added. The study was performed using the aneugen griseofulvin (GF) and the clastogen mitomycin C (MMC) as standard compounds. With both protocols GF induced a significant increase in MN frequency over controls in a dose-related manner at the lower concentrations tested (7.5 and 15 microg/ml). At the highest dose (30 microg/ml) the aneugen effect was substantially reduced. MN induction obtained with Prot. A was significantly higher ( approximately 3-fold) than with Prot. B at the most effective concentration. The aneugen effect induced by GF did not change when different cell densities were used, but again with Prot. A we obtained the highest effect. MN induced by MMC showed a dose- and time-dependent increase in both protocols. In contrast to GF, the greater clastogenic response induced by MMC in human liver fibroblasts was obtained with Prot. B, approximately 3-fold higher than Prot. A at the most effective concentration and approximately 2-fold with 24 h treatment at 0.17 microg/ml MMC. With GF, the FISH data in human liver fibroblasts (80% C+MN) were fairly consistent with those obtained in the rodent cell lines. In human whole blood cultures, the same dose used in our experiment produced a relatively higher percentage of C+MN. FISH analysis showed that MMC induced mainly MN containing acentric fragments rather than whole chromosomes. In conclusion we have demostrated that chemically induced genetic effects are strongly dependent on the cell culture employed, treatment schedule and intra- and post-treatment experimental conditions.

Chromosomal damage and ageing: effect on micronuclei frequency in peripheral blood lymphocytes

BACKGROUND

Instability in the organization and expression of the genetic material has been hypothesized as the basic mechanism of ageing.

OBJECTIVE

To quantify the effect of ageing on chromosomal damage as measured by spontaneous micronuclei (MN) frequency in peripheral blood lymphocytes.

METHOD

Analysis of a large population sample from two laboratories applying the cytokinesis-block technique and a third using traditional interphase analysis. The age-related effect on baseline level of micronuclei frequency and on cell proliferation measures was further investigated in a study of peripheral blood samples from healthy subjects.

RESULTS

There was an increase of MN frequency with age. The regression lines showed a positive slope and were statistically significant (P< 0.01) with a steeper trend for cytochalasin B-treated samples. An inverse correlation with age was detected for the percentage of binucleated cells in laboratories using cytochalasin B. This study confirms the increase of basal level of MN with age. A decrease by age in proliferation efficiency measured by the percentage of binucleated cells suggests an interference of age-related factors on cell division.

CONCLUSION

There is an increase in MN frequency with increasing age.

Micronuclei in blood lymphocytes and genetic polymorphism for GSTM1, GSTT1 and NAT2 in pesticide-exposed greenhouse workers

The frequency of micronuclei (MN) in cultured peripheral lymphocytes was used as a biomarker of genotoxic effects in 34 Italian pesticide-exposed greenhouse workers and 33 unexposed referents matched with the exposed workers for age and smoking habits. The possible influence of the genetic polymorphisms of xenobiotic metabolizing enzymes glutathione S-transferase M1 (GSTM1), T1 (GSTT1), and N-acetyltransferase 2 (NAT2) was also evaluated. To restrict the analysis primarily to cells that have divided once in vitro, MN were scored only in cells showing label after a 42-h incubation with bromodeoxyuridine (BrdU), as detected by immunofluorescence (anti-BrdU technique). Two different concentrations of BrdU (0.5 and 1 microg/ml) were compared. Individual frequencies of micronucleated cells (MNCs) obtained with the two concentrations of BrdU significantly correlated with each other (r=0.55, P<0.001). Higher mean MNCs frequencies (per 1000 cells) were detected among exposed smokers (9.0 at 0.5 microg/ml BrdU and 7.8 at 1 microg/ml BrdU) than in smoking referents (6.3 and 5.9, respectively). In multiple regression analysis controlling for age, sex, smoking and genotypes, a significant elevation of MNC frequency (P=0.004 at 1 microg/ml BrdU; P=0.052 at 0.5 microg/ml BrdU) was observed in greenhouse workers with a work history of extensive pesticide spraying (n=17). Increased MNC frequencies were also associated with ageing at 0.5 microg/ml BrdU, with the GSTM1-positive genotype at both 1 (P=0.028) and 0.5 (P=0.056) microg/ml BrdU in all subjects, and with the NAT2 fast acetylator genotype in smokers at 0.5 microg/ml BrdU (P=0.043). The results indicate that MN rates are increased in greenhouse workers, especially in those involved in pesticide spraying. The GSTM1 positive and NAT2 fast genotypes appear to be associated with elevated MNC frequencies, which contradicts with earlier results on elevated chromosomal aberration rates in GSTM1 null smokers and NAT2 slow subjects.

Micronucleus frequency in Gomel (Belarus) children affected and not affected by thyroid cancer

Cytogenetic monitoring was carried out on a group of children from Gomel (Belarus), one of the areas most severely affected by radioactive contamination following the accident at the Chernobyl nuclear power plant, in 1986. We performed the micronucleus test (MN) in binucleated lymphocytes of 42 children (mean age: 11+/-2.34 years), 16 of whom were affected by thyroid gland tumor. Thirty healthy children living in Pisa (mean age: 14.96+/-2.17 years) were enrolled in the study as controls. Thyroid tumor affected children living in Gomel showed a statistically significant increase in the frequency of micronucleated cells as compared with the healthy children from Pisa. Moreover, a significant correlation was found between MN frequency and both the presence of tumor and higher 137Cs contamination. In addition, higher 137Cs contamination was more frequently observed in tumor affected children. These results suggest that the increased MN frequency is attributable more to 137Cs contamination rather than to the presence of the tumor itself.

Cytogenetic study and FISH analysis in lymphocytes of systemic lupus erythematosus (SLE) and systemic sclerosis (SS) patients

Systemic lupus erythematosus (SLE) and systemic sclerosis (SS) are autoimmune diseases characterized by the presence of antibodies against ubiquitous self antigens. The presence of clastogenic factors (CF) capable of inducing chromosome breakage has also been reported in the plasma of some patients. We aimed to assess basal frequency of cytogenetic damage in lymphocytes and presence of CF in the plasma of two groups of SLE and SS patients displaying a different antibody status (ACA-/Scl70+ or ACA+/Scl70-), using the micronucleus (MN) assay and FISH analysis with a pancentromeric DNA probe. As compared with controls, we found significantly higher MN frequencies in SS patients, but not in SLE patients. In addition, our data showed a significant prevalence of C-MN in SLE and ACA-/Scl70+ patients and of C + MN in ACA+/Scl70- patients. We observed a positive response in three out of the five CF experiments performed on plasma of SS patients. The three patients whose plasma caused MN induction were subtyped as ACA-/Scl70+, whereas the other subjects had ACAs. The same tests on six SLE patients gave negative results.

Micronuclei assay and FISH analysis in human lymphocytes treated with six metal salts

The capability of some metal compounds for inducing micronuclei (MN) in human lymphocytes was studied. In this investigation, Al (III), Cd (II), Hg (II), Sb (V), Te (VI), and Tl (I) salts were considered. The FISH (fluorescence in situ hybridization) technique with a centromeric probe was coupled with the MN assay in binucleated cells in order to detect both centromere-positive MN (C+ MN) due to malsegregation phenomena and centromere-negative MN (C- MN) due to chromosome breakage. The blood of two young nonsmoking male donors was employed for all experiments. In both donors, all the tested metal compounds, with the exception of Tl(2)SO(4), showed a statistically significant increase of MN compared to controls, at least at one dose. FISH analysis revealed an increase in the fraction of C+ MN for Al, Cd, and Hg compounds, and of C- MN for the Sb salt; however, this was not a statistically significant increase. A different efficiency was observed for the different metal compounds, in particular, KSbO(3) and CH(3)HgCl, which were highly genotoxic, whereas the others showed minimal effects.

Detection of chromosome loss and gain induced by griseofulvin, estramustine, and vanadate in binucleated lymphocytes using FISH analysis

Cytochalasin B-blocked binucleated human lymphocytes from a healthy male donor were used to detect micronucleus induction and other aneuploidy events (chromosome loss and gain) after treatment with griseofulvin (GF), estramustine (EM), and sodium orthovanadate (Na(3)VO(4)). A two-color FISH was performed by using centromeric probes for chromosome 2 (FITC labeled) and the X chromosome (TRITC labeled) to measure chromosome loss and gain events in binucleated cells. GF induced mainly aneuploid binucleates involving the X chromosome, but this was not associated with preferential loss of one of the two chromosomes. EM preferentially induced aneuploidy of chromosome 2, and Na(3)VO(4) of the X chromosome. Our results indicate that chromosome malsegregation events (chromosome loss and/or gain) are probably not randomly induced, suggesting that different mechanisms leading to aneuploidy may be either chromosome-dependent or compound- and dose- related.

Different effects of newly isolated saponins on the mutagenicity and cytotoxicity of the anticancer drugs mitomycin C and bleomycin in human lymphocytes

Aim of the present paper was to assess by using the in vitro micronucleus (MN) test in human lymphocytes the effect of two plant extracts isolated from Blupeurum fruticosum (saponins) on the clastogenicity and cytotoxicity of the anticancer drugs mitomycin C (MMC) and bleomycin (BLM). One saponin showed a dose-dependent MMC-induced mutagenesis inhibition together with co-genotoxic effect on BLM-treated cultures. The remaining saponin did not significantly alter MN induction of both chemotherapeutic agents whereas it enhanced BLM cytotoxicity.

Aneuploidy and diploidy rates in sperm of five men after three-colour hybridization: indication of X chromosome-associated autosome 2 aneuploidy

The frequencies of aneuploidy and diploidy for chromosomes 2, X and Y in sperm nuclei of five nonsmoking normal donors were assessed by three-colour fluorescence in situ hybridization. We detected neither significant interindividual variability nor age effect (age range of the study group: 26-38 yr) on the mean frequencies of aneuploid and diploid sperm. Nullisomic sperm were observed more frequently than disomic sperm. In addition, sex chromosomal meiotic nondisjunction occurred at a higher rate than autosomal nondisjunction, and disomic sperm for the sex chromosomes were formed mainly by errors in the second meiotic division. Our data indicate that diploidy occurs at a very low frequency in comparison with aneuploidy. Furthermore, the overall proportion of X-bearing sperm nuclei aneuploid for chromosome 2 is significantly higher than that of Y-bearing sperm (0.14% vs. 0.05%, respectively; p < 0.001). This finding adds further evidence that autosomal aneuploidy can be preferentially associated with the presence of one of the two gonosomes.

Induction of aneuploidy by the antineoplastic drug estramustine in human lymphocytes

Estramustine (EM) is an antineoplastic drug used in the therapy of human prostatic carcinoma. The aim of our work was to evaluate the potential aneuploidogenic activity of estramustine, by analysing its cytogenetic effects induced in human lymphocytes. To estimate the ability of EM to induce mitotic spindle disturbances, two parameters were used: the presence of c-mitoses (according to the degree of chromatid spreading and contraction) and mitotic index evaluation (increase after exposure indicating the accumulation of mitoses). EM induced c-mitoses and mitotic index increases starting from the 4 microM dose: statistically significant increases were observed up to the highest dose (40 microM). A strong correlation between c-mitoses and mitotic index increase was found. The micronucleus (MN) assay combined with the fluorescence in situ hybridization technique with a pancentromeric DNA probe was also carried out. Compared to the control, EM induced significant MN increases in binucleated lymphocytes at two doses (8-16 microM). Moreover, we found that estramustine induced significant percentages of MN with positive hybridization signal at the same doses, confirming the presence of entire chromosomes in micronuclei. Additional experiments included induction of numerical and structural chromosome aberrations, and evaluation of sister chromatid exchanges (SCE) and satellited (D- and G-group chromosomes) chromosome associations. The results of numerical chromosome aberration analysis indicated that EM was positive in inducing a statistically significant increase in aneuploid cells and/or polyploid cells at all doses tested. On the basis of these observations, EM may be defined as a typical aneuploidy inducer, whereas it was not found to increase the frequency of structural chromosome aberrations and SCE frequency.

Spontaneous and induced aneuploidy in peripheral blood lymphocytes of patients with Alzheimer's disease

This study was aimed at assessing whether peripheral blood lymphocytes of patients with Alzheimer's disease (AD) show significant levels of aneuploidy and high percentages of cytogenetic events in vitro, indicating a predisposition to aneuploidy spontaneously, or after chemical treatment in vitro. A group of affected individuals and a group of unaffected, age-, sex- and smoking-habit-matched controls were identified. Lymphocytes were cultured for analysis of the following cytogenetic parameters: premature centromere division (PCD), satellite associations of acrocentric chromosomes (SA) and micronuclei (MN). In a subset of subjects, the fluorescence in situ hybridization (FISH) technique was combined with the MN assay, by means of a pancentromeric DNA probe for the detection of the presence of centric material. To evaluate the sensitivity to aneuploidogenic agents, in vitro treatment of lymphocytes of affected individuals was performed by adding griseofulvin, a chemical whose supposed target is microtubule-associated protein(s). Both the spontaneous frequency of MN and the frequency of PCD was significantly higher in patient cells than in controls. Furthermore, after application of the FISH technique, we found that the majority of MN were composed of whole chromosomes (because of the phenomenon of chromosome loss). Metaphase analysis for the detection of associative events between satellite regions of acrocentric chromosomes showed no differences between the two groups under study. Analysis of sensitivity to the aneuploidogen griseofulvin showed that the patient group was characterized by lower levels of MN induction compared with controls. Our data confirm that peripheral blood lymphocytes of AD patients are prone to undergo aneuploidy spontaneously in vitro and support the hypothesis that microtubule impairment might be associated with the disease.

Age-related increase of baseline frequencies of sister chromatid exchanges, chromosome aberrations, and micronuclei in human lymphocytes

Intra- and interindividual variations of baseline frequencies of cytogenetic end points in lymphocytes of human populations have been reported by various authors. Personal characteristics seem to account for a significant proportion of this variability. Several studies investigating the role of age as a confounding factor in cytogenetic biomonitoring found an age-related increase of micronucleus (MN) frequency, whereas contradictory results were reported for chromosomal aberrations (CAs) and sister chromatid exchanges (SCEs). We have quantitatively evaluated the effect of age on SCE, CA, and MN through the analysis of a population sample that included data from several biomonitoring studies performed over the last few decades in 12 Italian laboratories. The large size of the data set, i.e., more than 2000 tests for each end point, allowed us to estimate the independent effect of age, taking into account other covariates, such as sex, smoking habits, occupational exposure, and inter- and intralaboratory variability. A greater frequency of the mean standardized values by increasing of age was observed for all of the end points. A leveling off was evident in the last age classes in the trend of MN frequencies. Frequency ratios (FRs), which express the increase of the cytogenetic damage with respect to the first age classes, i.e., 1-19 years, were estimated using Poisson regression analysis after adjustment for the potential confounding factors and confirmed the increasing trend by age class for all three end points. The most dramatic increase was observed for MN, with a FR that approaches the value of 2 at the age class 50-59 (FR, 1.97; 95% confidence interval, 1.43-2.71) and remains substantially unchanged thereafter. The trend of FRs for CA is more homogeneous, with a constant rise even in the older classes, whereas the frequency of SCE increases with age to a lesser extent, reaching a plateau in the age class 40-49 and the maximum value of FR in the age class over 70 (FR, 1.14; 95% confidence interval, 1.07-1.23). In conclusion, our results point to an age-related increase of the chromosome damage in lymphocytes and emphasize the need to take into account the potential confounding effect of this variable in the design of biomonitoring studies based on chromosome damage.

Influence of GSTM1 and GSTT1 polymorphisms on the frequency of chromosome aberrations in lymphocytes of smokers and pesticide-exposed greenhouse workers

The influence of polymorphic glutathione S-transferases mu (GSTM1) and theta (GSTT1) on the rate of chromosome aberrations (CA) in peripheral lymphocytes of 30 pesticide-exposed floriculturists and 32 control subjects was studied. Pesticide exposure was not associated with elevated frequencies of CA. Among cigarette smokers, a statistically significant (p = 0.026) increase in baseline CA frequencies was observed in subjects with a homozygous deletion of the GSTM1 gene (GSTM1 null, n = 36) in comparison with those having at least one copy of the gene (GSTM1 positive, n = 26). This effect was mainly due to an excess of chromatid-type aberrations (p = 0.006). In addition, the few individuals (n = 5) deficient for both GSTM1 and GSTT1 showed significantly higher (p = 0.012) CA counts than GSTM1 positive GSTT1 nulls. Despite the limited number of subjects genotyped, the results seem to indicate an association between smoking induced CA frequencies and GSTM1 polymorphism, and a possible interaction between the GSTM1 and GSTT1 genotypes. The findings may be explained by the reduced detoxification capacity of GSTM1 null and GSTT1 null individuals.

Acrocentric chromosome frequency in spontaneous human lymphocyte micronuclei, evaluated by dual-colour hybridization, is neither sex- nor age-related

The aim of the present paper was to assess the occurrence of acrocentric chromosomes in spontaneous micronuclei (MN) of lymphocytes of 20 subjects (10 males and 10 females) of different ages by means of dual-colour hybridization with pancentromeric and acrocentric-specific DNA probes on the binucleate cells of each subject. MN were found to contain acrocentric chromosome(s) at an average frequency of 26.8%, as compared to a 60% frequency of centromere-positive MN (C + MN). As expected, the percentage of total C + MN increased significantly with increasing age both of all subjects (r = 0.695, p < 0.001) and women (r = 0.814, p < 0.01), while no relationship was found between the frequency of micronuclei containing acrocentric chromosome(s) and donor age. This study indicates that the frequency of MN containing acrocentric chromosomes is neither over-represented nor influenced by age or sex.