Analysis of the beta-globin gene in DNA of suspected thalassemic great apes.

DNA was recovered from teeth of 2 great ape skeletons, Pan troglodytes (Ptr) and Pongo pygmaeus (Ppy), belonging to a 19th-century zoological collection. The skeletons presented morphological alterations possibly associated with ß-thalassemia: Ptr had deformation of the calvaria and oro-maxillo-facial bones with porotic hyperostosis and extended osteoporotic lesions of the skeleton, while Ppy showed a general marked widening of the calvarial diploe but moderate osteoporotic signs on the post-cranial skeleton. We screened Ptr and Ppy for mutations in the ß-globin gene (exons 1, 2, and 3) because we suspected thalassemia. Ptr ß-globin sequences showed the highest degree of similarity with the human ones (99.8%), while those of Ppy were slightly different (98.2%). The results were consistent with the phylogenetic relationships between their β-globin gene sequences. We did not find any mutation in the ß-globin gene of Ptr and Ppy; therefore, we conclude that, in spite of skeletal alterations, the 2 subjects analyzed were not affected by ß-thalassemia.

Glutathione S-transferase T1 (GSTT1) and M1 (GSTM1) polymorphisms in a sample of the population in Northern Italy.

Glutathione S-transferase is a group of multifunctional enzymes important in the metabolism of xenobiotics. GSTT1 and GSTM1 are polymorphic in human populations. Since a relation between polymorphism and cancer susceptibility has been found, their distribution in human populations is of great interest. In the present study the distribution of GSTT1 and GSTM1 genotypes was studied in a total sample of 252 individuals of three localities of north-west Italy (Postua, Cavaglià and Biella) by PCR test. The frequencies of GSTT1 and GSTM1 "null" genotypes were respectively 7.94% and 34.92%. There are no significant differences between the populations studied in the GSTT1 "null" genotypes. On the other hand, for GSTM1 the frequency of gene deletion in Postua (25.5%) differs significantly (p < 0.01; chi-square test) from that of Biella (46.32%), which approaches the values indicated by most studies for Europeans (about 50%). The analysis of the frequencies of GSTT1 and GSTM1 polymorphisms among different age groups showed a lower frequency of negative genotypes in the older group, although not statistically confirmed.

Polymorphic Alu insertions in five North-West Italian populations.

We analyzed the frequencies of eight human polymorphic Alu insertion loci in population samples from five towns in North-West Italy: Postua, Cavaglià, Biella, Torino, and Genova. All loci under scrutiny were found to be polymorphic in all samples, with the two exceptions of locus A25 in Postua, which was fixed for the absence of the Alu element, and APO in Genova, where the Alu insertion was fixed. Heterozigosity values were highly variable in all loci. F(ST) values for all loci indicate that most of the variability is found within populations, while between population variability is lower. In the multidimensional scaling (MDS) analysis plot, the studied populations are separated from the main group represented by European populations. The Postua sample is set apart also from neighboring towns as Cavaglià and Biella, confirming previous observations of the demographic isolation of this population.

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.

Chromosomal aberrations, sister chromatid exchanges and high frequency cells in young patients with neurofibromatosis 1 (NF1).

Chromosomal aberrations (CAs), sister chromatid exchanges (SCEs) and high frequency cells (HFCs) have been assessed in peripheral blood lymphocytes of 10 neurofibromatosis (NF1) patients and 10 healthy controls. In both groups, the spontaneous rates and the induced (bleomycin for CA and MMC for SCE) frequencies were analyzed. No differences between cells from NF1 patients and controls were observed with respect to spontaneous or bleomycin induced CA. Spontaneous or MMC induced SCE frequencies were also similar in NF1 patients and controls. HFCs, on the contrary, were statistically lower in NF1 patients.

MFASAT: a new alphoid DNA sequence isolated from Macaca fascicularis (Cercopithecidae, Primates).

A new highly repeated DNA fragment isolated from Macaca fascicularis (MFASAT) is described. Our findings obtained by sequencing, Southern blot analysis, and fluorescent in situ hybridization (FISH) on metaphasic chromosomes strongly suggest that MFASAT can be considered as a member of the alphoid DNA family characteristic of Old World monkeys. The chromosomal localization of MFASAT, obtained by FISH, showed that this alphoid DNA is present in the peri-centromeric area of all the chromosomes. MFASAT showed a high degree of conservation when compared, by sequence alignment, to other Macaca species and Papio papio as expected for species with considerable genome conservation. A low degree of homology has been found comparing M. fascicularis alphoid DNA with a more distantly related Cercopithecidae species such as Cercopithecus aethiops.

Increased sister chromatid exchange and chromosomal aberration frequencies in psychiatric patients receiving psychopharmacological therapy.

Combinations of various psychotropic drugs are often used, sometimes for long periods, in the treatment of various forms of psychiatric disorders. This paper evaluates the cytogenetic consequences of daily exposure to polytherapy with antianxiety, antipsychotic and antimaniacal drugs by determining chromosomal aberrations (CA) and sister chromatid exchange (SCE) in peripheral blood samples. The study was performed with a group of 36 psychiatric patients: 18 receiving long-term treatment with lithium carbonate, combined with benzodiazepines (BD) and antipsychotic agents (Group A) and 18 treated with BD and antipsychotics (Group B). Among the latter, 7 patients had only been treated for 1 month (Group B1). The results reveal a significant increase (p<0.01) in cells with aberrations in the two groups of patients (A,B) compared to controls. Moreover, complex aberrations (dicentrics, rearrangements, chromatid exchanges) had a frequency of 0.63% in patients receiving long-term treatment compared to 0.11% in controls, corresponding to the general spontaneous rate. The mean frequency of SCE/cell and the percentage of cells with a high frequency of exchanges (HFC) also showed a highly significant difference compared to controls in both Group A and Group B. Group B1 (patients who only commenced treatment 1 month earlier) did not differ from the control group with regard to the frequency and type of chromosomal aberration or in relation to the mean frequency of SCE/cell. No significant differences were detected between Groups A and B both of which showed similar frequencies of cells with aberrations, SCE/cell and HFC. No correlations were observed in Group A between lithemia and the biological markers studied.

Baseline and mitomycin C (MMC)-induced sister-chromatid exchanges in XX and XY cells of Callithrix jacchus chimeric twins.

Lymphocytes from chimeric individuals of the species Callithrix jacchus (Primates) were examined to evaluate differences in the frequency of sister chromatid exchanges (SCE) between XX and XY cells. The aim was to discover whether SCE differ according to genetic sex and whether XX and XY cells show a different sensitivity to SCE inducing agents. This experimental model has enabled us to eliminate the possible differences caused by environmental factors. The results obtained do not reveal significant differences between male and female cells, in either the baseline SCE frequency or that induced by mitomycin C at concentrations of 0.01 and 0.03 microgram/ml. No significant differences were observed in the distribution of high SCE frequency cells (HFC), even if it is possible to observe a higher level of exchanges in XX cells in each trial. With regard to the phenotypic sex, there appears to be a trend towards slightly higher SCE rates in females, even if results are not statistically significant.

In vitro micronucleus induction by polymethyl methacrylate bone cement in cultured human lymphocytes.

Human lymphocytes cultured in vitro were used to assess the ability of polymethyl methacrylate (PMMA), currently used in orthopaedic surgery as bone cement, to induce micronuclei in binucleated cells. The results of the study show a significant increase in the micronucleus frequency in treated cultures and therefore the genotoxic effect of PMMA bone cement or its ingredients (methyl methacrylate, dimethyl para-toluidine and hydroquinone) usually present in self-curing methacrylate bone cement and released in small quantities after polymerisation. This effect is evident during the stage immediately after the polymerisation process, and after a certain period of time (5 days in our experimental model).

Lack of sister-chromatid exchange induction by polymethyl methacrylate bone cement in human lymphocytes cultured in vitro.

Human lymphocytes cultured in vitro were used to assess the ability of polymethyl methacrylate (PMMA), currently used in orthopedic surgery as bone cement, to induce sister-chromatid exchanges (SCE). Under the conditions used in this study, PMMA bone cement did not produce any significant increase in SCEs in phytohemagglutinin-stimulated human lymphocytes. However, a significant decline (p less than 0.05) in the proliferation rate index was observed, which might be an indicator of the cytotoxic effect of PMMA.