Carlos Daniel Golijow

DNA damage by cadmium and arsenic salts assessed by the single cell gel electrophoresis assay

Human exposure to metals is frequent due to their ubiquity, wide use in industry, and environmental persistence. Direct and indirect genotoxic effects of cadmium (Cd) and arsenic (As) were reported. However, the mechanisms of induction of genetic damage are not well known. The aim of the present work was to evaluate the degree of damage induced by Cd and As salts in a human lung fibroblasts cell line using the single cell gel electrophoresis assay (SCGE). MRC-5 cells were treated with cadmium chloride (CdCl(2)), cadmium sulfate (CdSO(4)), sodium arsenite (NaAsO(2)) and cacodylic acid (C(2)H(7)AsO(2)). A significant dose-dependent increment in the extent of DNA migration as well as in the percentage of cells with tails was observed (P<0.001) after treatment with CdSO(4) and NaAsO(2). Treatment with CdCl(2) induced a relatively low level of DNA strand breaks in comparison with that induced by CdSO(4). The increase migration observed with the three compounds could be originated either by the direct induction of DNA lesions or by the inhibition of excision repair mechanisms. On the other hand, cells treated with C(2)H(7)AsO(2) showed a decrease in the migration length with the three doses employed (P<0.001). The decrease in the rate of DNA migration could be a consequence of the induction of DNA cross-links by organic arsenicals.Cd and As salts induced DNA damage in fibroblast cells, detected as DNA migration in the single cell gel (SCG) assay. The distribution of DNA migration among cells as a function of dose revealed that the majority of exposed cells showed more DNA damage than cells obtained from control cultures. The potential for human exposure to both metals has been increased over the years due to the increment in their use. For this reason, elucidation of carcinogenic mechanisms is very important.

Analysis of adenocarcinoma of the colon and rectum: detection of human papillomavirus (HPV) DNA by polymerase chain reaction

Objective  The aim of the present work was to evaluate the presence of human papillomavirus genotypes in malignant and normal mucosa of the colon and rectum in order to determine if a relationship exists between HPV infection and colon neoplasms.

TNF-α and IL-10 promoter polymorphisms, HPV infection, and cervical cancer risk

Although the implication of genetic factors in cervical cancer development remains to be elucidated, accumulative epidemiological evidence suggests that polymorphisms of cytokine genes may be involved in the etiology of cervical carcinoma. Tumor necrosis factor alpha (TNF-α) and interleukin-10 (IL-10) are two multifunctional cytokines implicated in inflammation, immunity, and cellular organization, and were proposed to play important roles in cancer biology. In order to determine whether IL-10 -1082 (G/A) and TNF-α -238 (G/A) and -308 (G/A) polymorphisms are associated with susceptibility to cervical cancer, a case–control study of 122 cancer patients and 176 healthy controls was conducted. Cervical samples were genotyped for both TNF-α polymorphisms by PCR-RFLP assay. SNP-1082 from IL-10 gene was genotyped using pyrosequencing technology. The association between cervical cancer risk and the studied SNPs was evaluated by logistic regression. Under univariate analysis, none of these polymorphisms appeared associated with susceptibility of cervical cancer development or HPV infection. However, individuals carrying heterozygous genotype for TNF-α -238 polymorphism seem to be at lower risk for cervical cancer development, with borderline significance (OR = 0.42, P = 0.069), as well as those carrying heterozygous genotypes for IL-10 and TNF-α -238 (OR = 0.40, P = 0.08). In conclusion, these results suggest a potential effect of TNF-α -238 G/A in the reduction of cervical cancer risk in Argentine women, but not TNF-α -308 or IL-10. Larger studies are needed to fully understand the genetic predisposition for the development of cervical cancer.

p53 codon 72 genotypes in HPV infection and cervical disease

OBJECTIVE [corrected] An experimental study has indicated that individuals homozygous for the Arg-encoding allele of p53 gene may have an increased susceptibility to HPV-related cervical cancer but many epidemiological studies have failed to repeat this result. Many epidemiological studies have failed in the attempt to repeat this results. The aim of the present work was to investigate whether the p53 arginine allele confers a risk factor for cervical carcinogenesis. STUDY DESIGN Using PCR based technology, DNAs from 90 normal cervical samples and 205 abnormal cervical tissue scrapes were analyzed for the type of HPV present and p53 codon 72 polymorphism. RESULTS Non statistically significant differences were found for the frequencies of p53 genotypes in the different cytological/histological groups (chi2=1.4; P=0.97) nor for the risk for HPV infection (chi2=1; P=0.9). CONCLUSION This study showed that polymorphism at codon 72 of TP53 gene is not associated with an increased susceptibility to cervical disease and/or HPV infection in the Argentine women population.

Genetic variability and population structure in loci related to milk production traits in native Argentine Creole and commercial Argentine Holstein cattle

Many cattle breeds have been subjected to high selection pressure for production traits. Consequently, population genetic structure and allelic distribution could differ in breeds under high selection pressure compared to unselected breeds. Analysis of k-casein, aS1-casein and prolactin gene frequencies was made for Argentine Creole (AC) and Argentine Holstein (AH) cattle herds. The calculated FST values measured the degree of genetic differentiation of subpopulations, depending on the variances of gene frequencies.The AC breed had considerably more variation among herds at the aS1-casein and k-casein loci. Conservation strategies should consider the entire AC population in order to maintain the genetic variability found in this native breed.

XRCC2 R188H (rs3218536), XRCC3 T241M (rs861539) and R243H (rs77381814) Single Nucleotide Polymorphisms in Cervical Cancer Risk

Human Papillomavirus (HPV) is the main cause of cervical cancer and its precursor lesions. Transformation may be induced by several mechanisms, including oncogene activation and genome instability. Individual differences in DNA damage recognition and repair have been hypothesized to influence cervical cancer risk. The aim of this study was to evaluate whether the double strand break gene polymorphisms XRCC2 R188H G>A (rs3218536), XRCC3 T241M C>T (rs861539) and R243H G>A (rs77381814) are associated to cervical cancer in Argentine women. A case control study consisting of 322 samples (205 cases and 117 controls) was carried out. HPV DNA detection was performed by PCR and genotyping of positive samples by EIA (enzyme immunoassay). XRCC2 and 3 polymorphisms were determined by pyrosequencing. The HPV-adjusted odds ratio (OR) of XRCC2 188 GG/AG genotypes was OR = 2.4 (CI = 1.1–4.9, p = 0.02) for cervical cancer. In contrast, there was no increased risk for cervical cancer with XRCC3 241 TT/CC genotypes (OR = 0.48; CI = 0.2–1; p = 0.1) or XRCC3 241 CT/CC (OR = 0.87; CI = 0.52–1.4; p = 0.6). Regarding XRCC3 R243H, the G allele was almost fixed in the population studied. In conclusion, although the sample size was modest, the present data indicate a statistical association between cervical cancer and XRCC2 R188H polymorphism. Future studies are needed to confirm these findings.

Human Papillomavirus DNA and Oncogene Alterations in Colorectal Tumors

The aim of the present study is to determine the presence and molecular integrity of high-risk HPV types in colorectal adenocarcinomas and to assess whether viral DNA is related to common proto-oncogene alterations, such as k-ras mutations and c-myc gene amplification, in colorectal cancer. Seventy-five colorectal adenocarcinomas were screened for HPV infection using nested-PCR (MY09/11-GP5+/6+). HPV typing was performed by type-specific PCR for HPV 16 and HPV 18 DNA. Unidentified samples were subsequently sequenced to determine the viral genotype. The physical status of HPV was determined by a nested PCR approach for type-specific E2 sequences. C-myc amplification was assessed by co-amplification with β-globin as control locus, and mutation in k-ras codons 12 and 13 by ARMS-PCR. Overall, HPV was detected in thirty-three colorectal specimens (44%). HPV 16 was the prevalent type (16/75), followed by HPV 18 (15/75), HPV 31 (1/75) and HPV 66 (1/75). E2 disruption was detected in 56.3% of HPV 16 and in 40% of HPV 18 positive tumors. C-myc amplification was detected in 29.4% of cases, while k-ras mutations in 30.7%. There was no significant trend for HPV infection in tumors harboring either k-ras or c-myc alterations. This study demonstrates HPV DNA and viral integration in colorectal tumors, suggesting a potential role of this virus in colorectal carcinogenesis. There was no concurrence, however, of k-ras and c-myc activation with viral infection.

k-Casein gene frequencies support subdivision and historical origin of Argentine Creole cattle

Gene frequencies at the k-casein locus were estimated in six different herds (N = 180) of Argentinean Creole cattle. The results showed a strong influence of subdivision and independent evolution on the divergence of the observed gene frequencies. These results suggest that the population structure of these herds favor the maintenance of polymorphism, which is of crucial importance for the long-time survival of populations.

Y-Chromosome morphology and incidence of the 1 29 translocation in argentine creole bulls

The Argentine Creole is a local breed of cattle with high reproductive performance. This breed also shows resistance to many subtropical diseases. The cytogenetic status of the Argentine Creole, in particular the incidence of 1/29 translocation and Y-chromosome morphology, is not known in Argentina. Taking these factors into account, the cytogenetic study of 36 Argentinian Creole bulls was carried out. Heparinized blood samples were obtained and cultured for chromosome analysis. The results showed the absence of the 1/29 translocation in all the bulls analyzed and the presence of a submetacentric Y chromosome.

Herpes simplex virus and human papillomavirus infection in cervical disease in Argentine women.

Summary: The aim of the present study was to determine that prevalence of herpes simplex virus (HSV) type 1 and 2 in cervical samples from Argentine women and to assess the role of HSV-2 in cervical cancer. A sample of 79 normal and 200 neoplastic cervical tissues (35 invasive cervical carcinomas, 75 high-grade squamous intraepithelial lesions, 79 low-grade squamous intraepithelial lesions and 11 abnormal squamous cells of undermined significance) was analyzed for herpes simplex and human papillomavirus DNA using the polymerase chain reaction method. Viral genotyping was performed by single strand conformation polymorphisms and restriction fragment length polymorphisms. The overall prevalence of HSV was 21.5% in controls and 29% in cases. Among women with normal cytology, herpes simplex prevalence in HPV positive (20.8%) women was approximately the same as in negative (21.8%) women. HPV- and age- adjusted ORs of high-grade squamous intraepithelial lesions and invasive cervical carcinomas for HSV-2 were 1.4 (p = 0.6) and 1.6 (p = 0.5), respectively. The obtained results indicated that herpes simplex virus may not be involved in cervical cancer development. Future investigations are needed to provided conclusive evidence on the role of this pathogen in cervical cancer.