Sister chromatid exchange in patients with viral disease

Sister chromatid exchange (SCE) frequencies were studied in differentially stained chromosomes from lymphocytes of 17 patients with viral disease. The mean SCE score for the patients was 8.7 +/- 2.9 standard deviations. SCE scores were significantly elevated in the patients compared with the controls (p less than 0.01); however, variability in SCE means was observed in the patients. SCE elevations were also present in long term cultured Epstein Barr virus positive human B lymphocytes.     

Cytogenetic studies on blood lymphocytes from patients with Schistosoma mansoni

Chromosomal aberrations and sister chromatid exchange (SCE) frequencies were studied in peripheral blood lymphocytes from 10 patients with Schistosoma mansoni prior to initiation of chemotherapy. The mean frequencies of chromatid and chromosome breaks for the patients were 1.80 and 2.30%, respectively, which were significantly higher (P less than 0.01) than the means 0.35 and 0.30%, scored for 20 healthy controls. Significant increase in the mean frequency of SCEs in the patients (9.1 +/- 0.5 SCE/cell) was noticeable when compared with the controls (6.2 +/- 0.1 SCEs/cell). Reductions in the lymphocyte divisions and replications in the patients were also observed. These results indicate that infection with S. mansoni could have in vivo mutagenic effects on human chromosomes.     

Sister chromatid exchange in human chromosomes from normal individuals and patients with ataxia telangiectasia.

A new fluorescence plus Giemsa staining technique now makes the detection of sister-chromatid exchange (SCE) a relatively easy matter in cells containing 5-BrdU-substituted DNA. The technique has been applied to human cells to examine the distribution of SCE between different people and within different chromosomes. The results show: (1) That there were no large differences in the incidence of SCE between blood leukocyte chromosomes from male and female adults and newborn, and that similar frequencies were found in cells from two patients with ataxia telangiectasia which, nevertheless, showed the typical increases in chromosomal aberrations. (2) The distribution of SCE between chromosomes in the complement was found to be proportional to chromosome length, although the smaller chromosomes were under-represented, but not significantly so. (3) The distribution of SCE within chromosomes was nonrandom, with a deficiency in the centromeric and an excess in the mid-arm regions. There was no evidence for an excess of SCE in chromosome regions rich in AT DNA sequences. (4) The frequency of SCE is to some extent dependent of 5-BrdU concentration, but the influence of concentration is minimal within the range of from 1 to 160 muM. Human cells exposed over two cell cycles at these higher BrdU levels have around 14 SCE per cell-a frequency virtually identical with that observed in cultured cells from the Chinese hamster, wallaby, and rat kangaroo.     

Sister chromatid exchanges in cultured peripheral lymphocytes from twins

Summary Sister chromatid exchange points (SCE points) on individual chromosomes were studied in cultured lymphocytes from 11 monozygotic (MZ) and nine dizygotic (DZ) same-sexed pairs by means of sequential Q-banding and BUdR-Giemsa techniques. No statistically significant variation between unrelated individuals with respect to SCE points on specific chromosomes was found. Intrapair differences in the number of SCE points on specific chromosomes were not significantly smaller between MZ twin partners as compared with DZ partners. The results suggest that genetic factors do not play any major role in the frequency and distribution of SCE in normal subjects.     

Chromosome and SCE analysis in peripheral lymphocytes of persons occupationally exposed to cytostatic drugs handled with and without use of safety covers

The frequency of structural chromosome aberrations and sister-chromatid exchanges in peripheral blood lymphocytes of nurses handling cytostatic drugs without a safety cover is compared with that of individuals doing this work exclusively under a safety cover and with that of nurses working under similar conditions but not handling cytostatics. The mean yield of dicentric chromosomes, (4.3 +/- 0.7)/1000 cells, and acentric fragments, (15.4 +/- 1.4)/1000 cells, in the occupationally exposed group is significantly increased in comparison to individuals working with protection (dic: (1.1 +/- 0.4)/1000 cells, ace: (11.2 +/- 1.2)/1000 cells) and nurses not handling cytostatics (dic: (2.1 +/- 0.5)/1000 cells, ace: (9.9 +/- 1.1)/1000 cells). The frequency of chromatid breaks and SCE is not significantly different between these groups (p greater than 0.05).     

A decrease in sister chromatid exchange frequency during the prolonged cultivation of human lymphocytes

Sister chromatid exchange (SCE) frequency at different times of fixation was studied in human lymphocyte cultures obtained from 6 donors. No differences were found in the SCE frequency between human lymphocyte cultures fixed at 72 and 96 hours of incubation (10.61 +/- 0.85 and 10.15 +/- 0.81 SCE per cell, respectively). However, a decreased SCE frequency (8.11 +/- 0.36 SCE per cell) was observed in cultures fixed at 120 hours of incubation. For a more detailed studies, one lymphocyte culture was fixed at different times of incubation (from 56 to 128 hours, at each a 8 hours). A slight increase in SCE frequencies was found at the interval between 56 and 88 hours of incubation, while starting from 104 hours of incubation a marked decrease in the SCE frequency was observed. Time-dependent changes in the SCE frequency may be described by the equation y = -1.8614 + 0.3922x - (2.5183 x 10(-3))x2, where y is the number of SCEs per cell, and x--the duration of culture incubation in hours. The observed phenomenon may be associated with changes in proportion of T and B lymphocytes, or with heterochromatization of chromosomes during a prolonged cultivation, or with an early in vitro stimulation of the in vivo long-lived lymphocytes that may be more damaged than the in vivo short-lived and the in vitro late-stimulating ones.     

Frequency of sister-chromatid exchange (SCE) in bone-marrow cells of severely malnourished animals during early life

The frequency of sister-chromatid exchange (SCE) was examined in bone-marrow cells of 21-day-old Wistar rats malnourished during lactation and well-nourished controls of the same age. Malnutrition was obtained by increasing the litter size to 15 pups per mother. SCE were scored in 25 consecutive second-division metaphases in the femoral bone marrow cells from each animal. The average SCE in the malnourished animals was significantly higher than in the control group (p less than 0.01). The distribution of SCE per mitosis was also significantly higher in the malnourished animals (p less than 0.001). These results indicate that malnutrition per se during early life can increase SCE in the bone marrow of experimental animals.     

Quantitative analysis of sister chromatid exchanges in the cell]

Assuming a random nature of distribution of sister chromatid exchanges (SCE) in a karyotype, the formulae have been obtained allowing the calculation of the number of SCE that are overlooked because of a limited resolving power of the SCE detection method. The results obtained mean that the actual number of SCE is more than the observed one, the part of overlooked exchanges being increased with the heightening of the SCE level. Taking into account overlook exchanges, the formula has been obtained that makes possible the calculation of the expected number of SCE observed in any group of chromosomes. These results were applied in the analysis of the SCE distribution among chromosomes. A better conformity has been obtained between the expected results and the observed ones, than under the assumption that the observed SCE are distributed in proportion to the lengths of chromosomes. The obtained formulae are of use in interpreting the lack of the observed SCE in small chromosomes and the excess of them in large ones.     

Sister chromatid exchange (SCE) for the first time in Casertana pig breed

Lymphocyte cell cultures from 30 Casertana pigs (13 males and 17 females), reared in southern Italy, underwent the sister chromatid exchange (SCE) test. The Casertana pig is an endangered native breed from the region of Campania, raised chiefly half-wild. In the 1500 cells we studied, the mean SCE was 6.32+/-2.92 and SCE frequency did not follow a Poisson distribution. A higher mean value of SCE cell(-1) was found in the older group (SCE cell(-1)=6.68+/-2.95) compared with the younger (SCE cell(-1)=5.94+/-2.84), the difference being statistically significant (P<0.01). To our knowledge, this is the first investigation in a representative sample of Italian pig breed using the SCE test. Furthermore, this is the first report where the differences found in the mean SCE values were related to age in domestic species.     

A first comparative map of copy number variations in the sheep genome

We carried out a cross species cattle-sheep array comparative genome hybridization experiment to identify copy number variations (CNVs) in the sheep genome analysing ewes of Italian dairy or dual-purpose breeds (Bagnolese, Comisana, Laticauda, Massese, Sarda, and Valle del Belice) using a tiling oligonucleotide array with ~385,000 probes designed on the bovine genome. We identified 135 CNV regions (CNVRs; 24 reported in more than one animal) covering ~10.5 Mb of the virtual sheep genome referred to the bovine genome (0.398%) with a mean and a median equal to 77.6 and 55.9 kb, respectively. A comparative analysis between the identified sheep CNVRs and those reported in cattle and goat genomes indicated that overlaps between sheep and both other species CNVRs are highly significant (P<0.0001), suggesting that several chromosome regions might contain recurrent interspecies CNVRs. Many sheep CNVRs include genes with important biological functions. Further studies are needed to evaluate their functional relevance.     

Evaluation of genotoxic effects of Apitol (cymiazole hydrochloride) in vitro by measurement of sister chromatid exchange

Apitol, with cymiazole hydrochloride as the active ingredient, is used in bee-keeping against the ectoparasitic mite Varroa destructor. The preparation was evaluated for genotoxicity in cultured human peripheral blood lymphocytes. Sister chromatid exchange, the mitotic index and the cell proliferation index were determined for three experimental concentrations of Apitol (0.001, 0.01 and 0.1 mg/ml). All concentrations significantly (p < 0.001) increased the mitotic index (MI = 7.35+/-0.18%, 8.31+/-0.20% and 12.33+/-0.25%, respectively), the proliferative index (PI = 1.83+/-0.01, 1.84+/-0.01 and 1.88+/-0.02, respectively) and the frequency of sister chromatid exchange (SCE = 8.19+/-1.81, 8.78+/-1.80 and 13.46+/-1.88, respectively), suggesting that cymiazole hydrochloride has genotoxic potential.     

Scrotal dimensions and ejaculate characteristics of three breeds of sheep in tropical Nigeria

Scrotal circumference and semen characteristics of three breeds of sheep (Udda, Balami and Yankasa) indigenous to Nigeria and Southern Guinea Savannah zones of Africa were compared. The age, body weight, scrotal circumference and spermiogram of the rams were studied by standard techniques. The mean age, body weight, and scrotal circumference of the three breeds were not comparable with significant interbreed, but were with significant intrabreed differences. The mean ejaculate concentration of sperm cells (x 10 /ml) were: Udda, 3.8 +/- 0.050, Balami, 4.1 +/- 0.32, Yankasa, 4.5 +/- 0.11. The mean morphological sperm cell abnormalities for the Udda, Balami and Yankasa were; 7.5 +/- 2.1%, 4.5 +/- 0.58% and 6.0 +/- 0.87%, respectively, with significant inter- and intrabreed differences. There were significant intrabreed differences in the other semen traits, i.e., percent of live cells, percent of motility, mean volume and mean concentration. In all the breeds of sheep studied, the scrotal circumference and spermiogram were comparable to, and within the range reported for the exotic breed of rams.     

Distribution of sister chromatid exchanges on the mouse chromosomes in vivo with reference to the replication properties of the X chromosome

Frequency of sister chromatid exchanges (SCE) were recorded separately for different chromosomes from bone marrow cells of female mice of the two genetic strains (C3H/S and C57BL/6J). SCEs were evaluated following different doses of 5-bromo-2'-deoxyuridine (BrdU) as nine hourly i.p. injections. The SCE per cell increased with increasing BrdU doses which was slightly higher in C3H/S than in the C57BL/6J. SCEs per cell were variable at every treatment-strain combination, possibly reflecting the heterogeneous nature of the bone marrow cells. In general, there is a positive correlation between SCE per chromosome and the relative chromosome length. Total SCEs on one of the large chromosomes (most likely the X chromosome), however, are significantly higher than expected on the basis of relative length alone. Most of this increase is attributable to one of the homologues of this chromosome, which is not in synchrony with the rest of the chromosomes and may represent the late-replicating X. These results when viewed in the light of replication properties of the heterochromatinized X, suggest a direct involvement of DNA replication in SCE formation and may argue against the replication point as the sole site for the SCEs.     

Bioimpedance spectroscopy parameters of suspensions of young and old erythrocytes

The bioimpedance spectroscopy (BIS) parameters of the suspensions of young and old erythrocytes were studied. The separation of the erythrocytes by age was made by density gradient. The BIS parameters: extracellular (Re) and intracellular (Ri) fluid resistance, characteristic frequency (Fchar), cell membranes capacitance (Cm) and Alpha parameter of concentrate suspensions of young and old erythrocytes were measured on the BIA analyzer ABC-01 "Medass" in the frequency range 5-500 kHz. It was found that Re (300.4 +/- 30.0 Ohm and 261.2 +/- 21.8 Ohm for old and young respectively, p < 0.05), Ri (86.6 +/- 9.1 Ohm and 73.4 +/- 7.3 Ohm for old and young respectively, p < 0.001) and Alpha (0.305 +/- 0.003 and 0.302 +/- 0.001 for old and young respectively, p < 0.05) of the old erythrocytes suspensions were higher, than of the young one, and Fchar (308.3 +/- 42.0 kHz and 347.4 +/- 48.0 kHz for old and young respectively, p <0.05) and Cm (99.3 +/- 10.1 pF and 112.8 +/- 6.3 pF for old and young respectively, p < 0.01) of the old erythrocytes were lower, than of the young one. The found differences between electrical properties of the suspensions of young and old erythrocytes were obviously determined by the alterations of the red blood cells during aging (growth of intracellular hemoglobin concentration, erythrocytes rapprochement because of diminishing of surface negative charge, increase of red blood cell sphericity and cell membrane permeability for ions). Thus the BIS parameters are related to the erythrocyte aging.     

Sister-chromatid exchanges in lymphocytes from patients with Schistosoma hematobium

Sister-chromatid exchange (SCE) frequencies were studied in peripheral blood lymphocytes from 19 patients (13 males and 6 females) with Schistosoma hematobium, prior to the initiation of chemotherapy. The mean frequency of SCE per metaphase for the patients (both sexes) was 10.4 +/- 4.2 which was significantly higher (P less than 0.01) than the mean SCE (6.4 +/- 1.1) score for 35 healthy controls. A highly significant reduction in lymphocyte division and delay in cell-cycle progression as a result of infection were also noticed. These data indicate that infection with S. hematobium could increase SCEs in the host somatic cells.     

Analysis of the frequency and distribution of sister chromatid exchanges in cultured human lymphocytes

Summary Lymphocytes from 20 normal subjects (11 male and 9 female) were examined for the frequency and location of sister chromatid exchanges (SCE) by the BrdU—Giemsa method. The mean frequency of SCE was 6.37 with little significant variation. One subject had a high number of exchanges in chromosome 1 while the remainder showed a random distribution of exchanges between chromosomes. The frequency of exchanges generally increased with chromosome length. However, chromosome 1, 2 and the B group had more exchanges than expected while the E, F and G groups had less than expected. The distribution of exchanges in chromosomes 1, 2 and the B group was non-random with a concentration of exchanges below the centromere and to a lesser extent on the distal portion of the long arm. The majority of exchanges appeared to occur at the junction between the dark and light G bands. It is suggested that the concentration of exchanges may reflect differences in BrdU incorporation along the length of the chromosome.     

Biomarkers of genotoxicity and genomic instability in a non-human primate, Cebus libidinosus (Cebidae, Platyrrhini), exposed to nitroimidazole derivatives

The genotoxicity of two nitroimidazole derivatives, ornidazole (ONZ) and metronidazole (MTZ) in the peripheral blood lymphocytes of Cebus libidinosus (CLI) (Primates, Cebidae) was assessed. Endpoints measured included sister chromatid exchange (SCE) frequency, cell proliferation kinetics (CPK), replication index (RI), mitotic index (MI), and damage incidence in or near CLI heterochromatin regions. MI and SCE values following ONZ or MTZ treatments were significantly different (p<0.001) from control. SCE frequency per chromosome was not proportional to chromosome length. The chromosomes most affected for SCE were 1, 2, 4, 6, 11-13, 17, and 18, many of which possess interstitial or terminal heterochromatin. In the CLI genome, chromosomes 11 and 17 showed higher susceptibility to damage RI was the only biomarker that did not show statistically significant differences between control and treated cultures. C. libidinosus bands 11q1.4 and 11q1.5 may be hot-spots in the context of nitroimidazole exposure.     

Haemocompatibility of extracorporeal circulation technique with autooxygenation: influence on platelet function and homologous blood requirement.

Forty male patients: group A-autooxygenation and group B-bubble oxygenator used in extracorporeal circulation (ECC) were studied to evaluate the haemocompatibility of 2 types of ECC. The Plt count dropped significantly in group B patients: -73% of initial value vs only -27% in group A, (p less than 0.001). In both groups a rise in BTG was shown, but higher in group B, p less than 0.001. At the end of CPB aggregation decreased only slightly in group A after epinephrine and 4-ADP, and decreased hardly in group B with the significant difference between two groups (p less than 0.02 and p less than 0.001, respectively). In group A the mean blood loss was 278 +/- 49 ml/m2 and 483 +/- 67 ml/m2 in group B, p less than 0.001. The mean blood transfusion in group A and B was 198 +/- 82 ml/m2 and 427 +/- 85 ml/m2, respectively (p less than 0.001). We are positive that the elimination of artificial oxygenator from the ECC diminished markedly the decline in Plt count and Plt activation during CPB.     

Genetic diversity and differentiation of dromedarian camel of India

Estimation of genetic variability and relationship among different livestock breeds is important for management of genetic resources for their sustainable utilization and conservation. This is more important when the livestock species, like camel, have shown a sharp decline in head count during the last decade. In the present study we estimated genetic variability and relationship among four camel breeds of India using 23 microsatellite loci. A total of 252 alleles were observed across all the four populations with mean number of alleles per locus as 8.04, 7.30, 6.39, and 7.43 for Bikaneri, Jaisalmeri, Kutchi, and Mewari breeds, respectively. The mean observed heterozygosity of the four breeds were 0.58, 0.57, 0.56, and 0.60 for Bikaneri, Jaisalmeri, Kutchi, and Mewari breeds, respectively and were lower than expected heterozygosity values. The mean estimates of F statistics were 0.227+/-0.044 (F(IT)), 0.157+/-0.038 (F(IS)), and 0.082+/-0.019 (F(ST)). The values were significantly different from zero for all the three measures and point towards the existence of population structure and moderate differentiation in four camel breeds. The exact test also indicated significant population differentiation (P < 0.001). The analysis of molecular variance revealed 12% of the variation attributed to among populations and 88% within populations. Sixty-nine percent of the individuals could be correctly assigned using "leave one out" procedure. All the individuals of Mewari and 42 out of 44 Jaisalmeri were correctly assigned. The existence of strong population structure in Jaisalmeri and Mewari camel was further substantiated by Nei's standard genetic distance as well as interindividual allele sharing distance. Thus these two breeds owing to selection for specific traits are distinct from other camel breeds.     

Constitutive heterochromatin polymorphism and chromosome damage in viral hepatitis

The frequencies of chromosomal aberrations and sister-chromatid exchanges (SCEs) were scored in relation to constitutive heterochromatin in 100 patients with viral hepatitis B, 100 patients with viral hepatitis A and 100 age- and sex-matched normal controls. 23.4%, 15% and 4% of the cells showed chromosomal aberrations in patients with hepatitis B, hepatitis A and normal controls respectively. Non-random involvement of chromosomal aberrations were also noted in chromosome 1 of patients with hepatitis B and A as compared to normal controls. The frequencies of SCEs (mean +/- S.D.) were found to be 10.40 +/- 2.83 in hepatitis B and 8.70 +/- 2.34 in hepatitis A. These values were significantly higher than the SCE frequency (mean +/- S.D.) of 5.88 +/- 2.25 observed in normal controls (P less than 0.001). The intra-chromosomal distribution of SCEs revealed a relatively increased incidence of SCEs in chromosome 1 of patients with hepatitis B and A as compared to normal controls. Analysis of constitutive heterochromatin polymorphism showed chromosome 1 qh+ to be the most frequent variant in patients with hepatitis B and A as compared to normal controls. The increased involvement of C-band variant 1 qh+ in patients with hepatitis B and A as compared to normal controls may indicate that extra heterochromatin offers additional sites for viral integration.