Increased levels of chromosomal aberrations and DNA damage in a group of workers exposed to formaldehyde.

Formaldehyde (FA) is a commonly used chemical in anatomy and pathology laboratories as a tissue preservative and fixative. Because of its sensitising properties, irritating effects and cancer implication, FA accounts probably for the most important chemical-exposure hazard concerning this professional group. Evidence for genotoxic effects and carcinogenic properties in humans is insufficient and conflicting, particularly in regard to the ability of inhaled FA to induce toxicity on other cells besides first contact tissues, such as buccal and nasal cells. To evaluate the effects of exposure to FA in human peripheral blood lymphocytes, a group of 84 anatomy pathology laboratory workers exposed occupationally to FA and 87 control subjects were tested for chromosomal aberrations (CAs) and DNA damage (comet assay). The level of exposure to FA in the workplace air was evaluated. The association between genotoxicity biomarkers and polymorphic genes of xenobiotic-metabolising and DNA repair enzymes were also assessed. The estimated mean level of FA exposure was 0.38±0.03 ppm. All cytogenetic endpoints assessed by CAs test and comet assay % tail DNA (%TDNA) were significantly higher in FA-exposed workers compared with controls. Regarding the effect of susceptibility biomarkers, results suggest that polymorphisms in CYP2E1 and GSTP1 metabolic genes, as well as, XRCC1 and PARP1 polymorphic genes involved in DNA repair pathways are associated with higher genetic damage in FA-exposed subjects. Data obtained in this study show a potential health risk situation of anatomy pathology laboratory workers exposed to FA (0.38 ppm). Implementation of security and hygiene measures may be crucial to decrease risk. The obtained information may also provide new important data to be used by health care programs and by governmental agencies responsible for occupational health and safety.

The Brazilian founder mutation TP53 p.R337H is uncommon in Portuguese women diagnosed with breast cancer.

Since the first studies reporting the TP53 p.R337H mutation as founder mutation in Southern and Southeastern Brazil, there has been controversy on its origin. Preliminary analysis of a small subset of Brazilian mutation carriers revealed that the haplotype incided on a Caucasian background. The vast majority of carriers identified today reside in Brazil or, if identified in other countries, are Brazilian immigrants. To our knowledge, the only two exceptions of carriers without a recognizable link with Brazil are two European families, from Portugal and Germany. Haplotype analysis in the Portuguese family revealed the same haplotype identified in Brazilian individuals, but in the German family, a distinct haplotype was found. Knowing that a significant proportion of women with breast cancer (BC) in Southern Brazil are p.R337H carriers, we analyzed p.R337H in a Portuguese cohort of women diagnosed with this disease. Median age at diagnosis among the first 573 patients tested was 60 years and 100 (17.4%) patients had been diagnosed at or under the age of 45 years. Mutation screening failed to identify the mutation in the 573 patients tested. These results are in contrast with the mutation frequency observed in a study including 815 BC-affected women from Brazil, in which carrier frequencies of 12.1 and 5.1% in pre- and postmenopausal women were observed, respectively. These findings suggest that the Brazilian founder mutation p.R337H, the most frequent germline TP53 mutation reported to date, is not a common germline alteration in Portuguese women diagnosed with BC.

Mechanistic insights into the cytotoxicity and genotoxicity induced by glycidamide in human mammary cells.

Acrylamide (AA) is a well-known industrial chemical classified as a probable human carcinogen. Benign and malignant tumours at different sites, including the mammary gland, have been reported in rodents exposed to AA. This xenobiotic is also formed in many carbohydrate-rich foods prepared at high temperatures. For this reason, AA is an issue of concern in terms of human cancer risk. The epoxide glycidamide (GA) is thought to be the ultimate genotoxic AA metabolite. Despite extensive experimental and epidemiological data focused on AA-induced breast cancer, there is still lack of information on the deleterious effects induced by GA in mammary cells. The work reported here addresses the characterisation and modulation of cytotoxicity, generation of reactive oxygen species, formation of micronuclei (MN) and quantification of specific GA-DNA adducts in human MCF10A epithelial cells exposed to GA. The results show that GA significantly induces MN, impairs cell proliferation kinetics and decreases cell viability at high concentrations by mechanisms not involving oxidative stress. KU55933, an inhibitor of ataxia telangiectasia mutated kinase, enhanced the cytotoxicity of GA (P < 0.05), supporting a role of this enzyme in regulating the repair of GA-induced DNA lesions. Moreover, even at low GA levels, N7-GA-Gua adducts were generated in a linear dose-response manner in MCF10A cells. These results confirm that human mammary cells are susceptible to GA toxicity and reinforce the need for additional studies to clarify the potential correlation between dietary AA exposure and breast cancer risk in human populations.

Endovascular treatment of type B dissection in patients with Marfan syndrome: mid-term outcomes and aortic remodeling.

OBJECTIVES: To evaluate the mid-term outcomes, and the aortic remodeling in Marfan syndrome (MFS) patients with type B dissection that were treated with endovascular repair. BACKGROUND: MFS is a relative contraindication to thoracic endovascular aortic repair (TEVAR). Mid-term aortic outcomes data in MFS after TEVAR are limited, and the occurrence of late events remains unclear. METHODS: Of 89 patients that underwent TEVAR between September 2002 and February 2011, 10 patients with mid-term follow-up fulfilled the Ghent criteria for MFS and complicated type B dissection. High risk for open surgery was documented in 90%. RESULTS: The mean age was 35.1 ± 9.4 years and all patients presented with acute aortic syndrome complicating a chronic type B dissection (DeBakey type IIIb). Five patients underwent a Bentall surgical procedure previous to endovascular repair, and in four patients initial TEVAR was followed by surgery of the ascending aorta. Treatment was limited to endovascular repair in only one patient. In-hospital mortality was 10%. At a mean follow-up of 59.6 ± 38.9 months, the cumulated mortality was of 20% and late mortality 11.1%. The rate of secondary endoleak was 44.4%, and late reintervention of 33.3%. Survival freedom from cardiovascular death at 8 years was 80.0%, and positive remodeling was documented in 37.5% of patients. CONCLUSIONS: Our results suggest that TEVAR is feasible, safe, and associated with a high reintervention rate and reduced rate of positive aortic remodeling in patients with Marfan syndrome. Survival at 8 years was comparable to contemporary series of open repair.

Induction of sister chromatid exchange by acrylamide and glycidamide in human lymphocytes: role of polymorphisms in detoxification and DNA-repair genes in the genotoxicity of glycidamide.

Acrylamide (AA) is a probable human carcinogen generated in carbohydrate-rich foodstuffs upon heating. Glycidamide (GA), formed via epoxidation, presumably mediated by cytochrome P450 2E1, is considered to be the active metabolite that plays a central role in the genotoxicity of AA. The aim of this work was to evaluate the cytogenetic damage induced by AA and GA in cultured human lymphocytes by use of the sister chromatid exchange (SCE) assay. Furthermore, this report addresses the role of individual genetic polymorphisms in key genes involved in detoxification and DNA-repair pathways (BER, NER, HRR and NHEJ) on the induction of SCE by GA. While AA induced the number of SCE/metaphase only slightly, especially for the highest concentration tested (2000µM), GA markedly induced SCEs in a concentration-dependent manner up to concentrations of 750µM, leading to an increase in SCEs of up to about 10-fold compared with controls. By combining DNA damage in GA-treated lymphocytes and data on polymorphisms, associations between the induction of SCEs with GSTP1 (Ile105Val) and GSTA2 (Glu210Ala) genotypes are suggested.

DNA damage and susceptibility assessment in industrial workers exposed to styrene.

Styrene is a widely used chemical in the manufacture of synthetic rubber, resins, polyesters, and plastics. The highest levels of human exposure to styrene occur during the production of reinforced plastic products. The objective of this study was to examine occupational exposure to styrene in a multistage approach, in order to integrate the following endpoints: styrene in workplace air, mandelic and phenylglyoxylic acids (MA + PGA) in urine, sister chromatid exchanges (SCE), micronuclei (MN), DNA damage (comet assay), and genetic polymorphisms of metabolizing enzymes (CYP2E1, EPHX1, GSTM1, GSTT1, and GSTP1). Seventy-five workers from a fiberglass-reinforced plastics factory and 77 unexposed controls took part in the study. The mean air concentration of styrene in the breathing zone of workers (30.4 ppm) and the mean concentration of urinary metabolites (MA + PGA = 443 ± 44 mg/g creatinine) exceeded the threshold limit value (TLV) and the biological exposure index (BEI). Significantly higher SCE frequency rate and DNA damage were observed in exposed workers, but MN frequency was not markedly modified by exposure. With respect to the effect of genetic polymorphisms on different exposure and effect biomarkers studied, an increase in SCE levels with elevated microsomal epoxide hydrolase activity was noted in exposed workers, suggesting a possible exposure-genotype interaction.

Genetic polymorphisms in detoxification and DNA repair genes and susceptibility to glycidamide-induced DNA damage.

Acrylamide (AA) is a probable human carcinogen formed in carbohydrate-rich foodstuffs upon heating. Glycidamide (GA), the AA metabolite formed by epoxidation, is considered the ultimate genotoxic agent. In this study, the in vitro genotoxic potential of AA and GA in human whole blood leukocytes was compared using the alkaline comet assay. Although AA did not induce significant DNA damage in the concentrations tested (up to 1000 µM), GA markedly increased the percentage of tail DNA at concentrations ≥250 µM. Further, this study addressed the role of genetic polymorphisms in key genes involved in metabolism and DNA repair pathways (BER, NER, HRR, and NHEJ) on GA-induced genotoxicity assessed by the alkaline comet assay. The results obtained suggested associations between DNA damage and polymorphisms of BER (MUTYH Gln335His and XRCC1 Gln399Arg) and NER (XPC Ala499Val) genes, either alone or in combination.

Genotoxic damage in hospital workers exposed to ionizing radiation and metabolic gene polymorphisms.

Of all workers exposed globally to synthetic sources of radiation, medical personnel represent the largest group, but receive relatively low doses. Accidental or therapeutic acute radiation exposure of humans was observed to induce various forms of cytogenetic damage, including the possibility of increasing the incidence of micronuclei (MN) and chromosomal aberrations (CA). The aim of this study was to assess occupationally induced chromosomal damage in a large population of hospital workers exposed to low doses of ionizing radiation (IR). The cytokinesis-block MN and comet assays were used to examine peripheral blood lymphocytes (PBL) of 31 exposed workers to IR and 33 control subjects corresponding in gender, age, and smoking. Glutathione S-transferases (GSTM1, GSTT1, and GSTP1) are postulated to be involved in the detoxification of endogenous and exogenous genotoxicants. The association between these biomarkers and polymorphic genes of xenobiotic metabolizing enzymes was thus also assessed. MN frequency was significantly higher in the exposed subjects compared controls. Comet assay results showed a significant increase of tail length in workers exposed to IR. Data obtained suggest that GSTM1, GSTT1, and GSTP1 polymorphism do not modify significantly the genotoxic potential of IR. Therefore, the exposed medical personnel need to carefully apply radiation protection procedures and minimize, as low as possible, IR exposure to avoid possible genotoxic effects.

Prevention of Radial Artery Occlusion of 3 Hemostatic Methods in Transradial Intervention for Coronary Angiography.

OBJECTIVES: The main objective of this study was to compare the efficacy of 3 hemostatic methods for the prevention of early radial artery occlusion (RAO): standard patent hemostasis, patent hemostasis with ulnar compression or the ulnar artery transient compression facilitating radial artery patent hemostasis (ULTRA) method, and facilitated hemostasis with a hemostatic disc. BACKGROUND: There are no prospective randomized studies that compare early RAO rates with the 3 most used nonocclusive hemostatic methods. METHODS: This was a prospective, longitudinal, comparative, and randomized study. The final population analyzed was 1,469, and they were randomized into 3 groups: 491 patients in group 1 with standard patent hemostasis, 490 patients in group 2 with the ULTRA method, and 488 patients in group 3 with facilitated hemostasis with a hemostatic disc. RESULTS: The RAO rate at 24 hours of the total population analyzed was 4.6%. By hemostasis groups, it was 3.6% for patent hemostasis, 5.5% for the ULTRA method, and 4.7% for facilitated hemostasis with a hemostatic disc, with no statistical difference among the 3 groups (P = 0.387). At 30 days, the overall rate of RAO was 1.8%, and by groups, it was 1.4% for the patent hemostasis group, 1.8% for the ULTRA method group, and 2.2% for the facilitated hemostasis with a hemostatic disc group, respectively (P = 0.185). CONCLUSIONS: The rates of RAO at 24 hours evaluated by plethysmography oximetry and confirmed by ultrasound among 3 current radial hemostasis methods (ie, patent hemostasis, the ULTRA method, and facilitated hemostasis with a hemostatic disc) are not different.

Bioprosthetic valve failure. Comparative trial of two balloon-expandable transcatheter heart valve systems in intermediate-risk patients: a propensity score analysis.

BACKGROUND: The comparative mid and long-term durability, including the rates of bioprosthetic valve failure (BVF) of the Sapien XT® and Sapien 3® transcatheter heart valve (THV) in patients with intermediate surgical risk has not been reported. METHODS: Consecutive intermediate-risk patients with severe aortic stenosis from the Mexican registry of transcatheter aortic valve replacement (TAVR) with Sapien® THVs were included. The primary endpoint was to compare the BVF rate between THVs at 2 years of follow-up. Secondary endpoints were comparisons of the composite of global mortality, cardiovascular mortality, and neurological events at 30 d and 24 months of follow-up. RESULTS: During 2014-2019, 115 (60 Sapien XT® and 55 Sapien 3®) patients met the inclusion criteria in five medical centres. The mean age was 77.3 ± 8.4 years. The average Society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM) was 5.6 ± 2.9. There was no statistically significant difference between the groups in BVF rate. At 30 d, overall, cardiovascular and non-cardiovascular mortality was 4.3%, 2.6%, and 1.7%, respectively. Neurological events rate was 1.73%. The mean long-term follow-up was 25.3 ± 14.2 months with an overall mortality of 9.56% but lower for the Sapien 3® group (15% vs. 3.6%, p=.037). The only independent predictor of composite mortality and neurological events that occurred in the long term was using a Sapien XT® [OR 1.6, CI 95%, 1.0-24.9; p=.049]. CONCLUSIONS: The BVF rate at 25 months of follow-up was similar with the XT and S3 systems. During this follow-up period, the major composite events of death from any cause and neurological events were significantly lower with the S3 system.

ACMA (9-amino-6-chloro-2-methoxy acridine) forms three complexes in the presence of DNA.

The interaction of ACMA (9-amino-6-chloro-2-methoxy acridine) (D) with DNA (P) has been studied by absorbance, fluorescence, circular dichroism, spectrophotometry, viscometry and unwinding electrophoresis. A T-jump kinetic study has also been undertaken. The experimental data show that, totally unlike other drugs, ACMA is able to form with DNA three complexes (PD(I), PD(II), PD(III)) that differ from each other by the characteristics and extent of the binding process. The main features of PD(I) fulfil the classical intercalation pattern and the formation/dissociation kinetics have been elucidated by T-jump techniques. PD(II) and PD(III) are also intercalated species but, in addition to the dye units lodged between base pairs, they also bear dye molecules externally bound, more in PD(III) relative to PD(II). A reaction mechanism is put forward here. Comparison between absorbance, fluorescence and kinetic experiments has enabled us to determine the binding constants of the three complexes, namely (6.5 ± 1.1) × 10(4) M(-1) (PD(I)), (5.5 ± 1.5) × 10(4) M(-1) (PD(II)) and (5.7 ± 0.03) × 10(4) M(-1) (PD(III)). The Comet assay reveals that the ACMA binding to DNA brings about genotoxic properties. The mutagenic potential studied by the Ames test reveals that ACMA can produce frameshift and transversion/transition mutations. ACMA also is able to produce base-pair substitution in the presence of S9 mix. Moreover, the MTT assays have revealed cytotoxicity. The biological effects observed have been rationalized in light of these features.

Distal Radial Artery Approach to Prevent Radial Artery Occlusion Trial.

OBJECTIVES: The aim of this study was to compare the rate of proximal radial artery occlusion (RAO) with Doppler ultrasound between distal and conventional radial access 24 h and 30 days after a transradial coronary procedure. BACKGROUND: The use of distal radial access to prevent proximal RAO (PRAO) in the proximal segment at 24 h and 30 days after a procedure, compared with conventional radial access, is unknown. METHODS: This was a prospective, comparative, longitudinal, randomized study. A total of 282 patients were randomized to either proximal radial access (n = 142) or distal radial access (n = 140) to evaluate the superiority of the distal approach in the prevention of PRAO with Doppler ultrasound 24 h and 30 days after a transradial coronary procedure. RESULTS: In the per protocol analysis, the rates of PRAO at 24 h and 30 days were 8.4% and 5.6% in the proximal group and 0.7% and 0.7% in the distal group, respectively (24 h: odds ratio [OR]: 12.8; 95% confidence interval [CI]: 1.6 to 100.0; p = 0.002; 30 days: OR: 8.2; 95% CI: 1.0 to 67.2; p = 0.019). In an intention-to-treat analysis, the 24-h and 30-day rates of PRAO were 8.8% and 6.4% for proximal radial access and 1.2% and 0.6% in the distal radial access group (24 h: OR: 7.4; 95% CI: 1.6 to 34.3; p = 0.003; 30 days: OR: 10.6; 95% CI: 1.3 to 86.4; p = 0.007). CONCLUSIONS: Distal radial access prevents RAO in the proximal segment at 24 h and 30 days after the procedure compared with conventional radial access.

Biological assays and noncovalent interactions of pyridine-2-carbaldehyde thiosemicarbazonecopper(II) drugs with [poly(dA-dT)](2), [poly(dG-dC)] (2), and calf thymus DNA.

The interaction of the Cu(II) drugs CuL(NO(3)) and CuL'(NO(3)) (HL is pyridine-2-carbaldehyde thiosemicarbazone and HL' is pyridine-2-carbaldehyde 4N-methylthiosemicarbazone, in water named [CuL](+) and [CuL'](+)) with [poly(dA-dT)](2), [poly(dG-dC)](2), and calf thymus (CT) DNA has been probed in aqueous solution at pH 6.0, I = 0.1 M, and T = 25 degrees C by absorbance, fluorescence, circular dichroism, and viscosity measurements. The results reveal that these drugs act as groove binders with [poly(dA-dT)](2), with a site size n = 6-7, whereas they act as external binders with [poly(dG-dC)](2) and/or CT-DNA, thus establishing overall electrostatic interaction with n = 1. The binding constants with [CuL'](+) were slightly larger than with [CuL](+). The title compounds display some cleavage activity in the presence of thiols, bringing about the rupture of the DNA strands by the reactive oxygen species formed by reoxidation of Cu(I) to Cu(II); this feature was not observed in the absence of thiols. Mutagenic assays performed both in the presence and in the absence of S9 mix, probed by the Ames test on TA 98, TA 100, and TA 102, were negative. Weak genotoxic activity was detected for [CuL](+) and [CuL'](+), with a significative dose-response effect for [CuL'](+), which was shown to be more cytotoxic in the Ames test and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cell proliferation assays. Methylation of the terminal NH(2) group enhances the antiproliferative activity of the pyridine-2-carbaldehyde thiosemicarbazones.

Cytogenetic and DNA damage on workers exposed to styrene.

Styrene is a commercially important chemical widely used in the manufacture of synthetic rubber, resins, polyesters and plastics. The highest levels of human exposure to styrene occur during the production of reinforced plastic products. The objective of this work was to evaluate both DNA and cytogenetic damage in styrene-exposed workers, analysing only non-smoker individuals. Environmental levels of styrene and urinary concentrations of mandelic and phenylglyoxylic acids were determined, and genetic damage was studied by means of micronucleus (MN) test, sister chromatid exchanges (SCEs) and comet assay. Fifty-two fibreglass-reinforced plastics workers and 54 controls took part in the study. The mean air concentration of styrene in the breathing zone of workers exceeded the threshold limit value, and 24 workers exceeded the biological exposure index. A strong and significant correlation was found between styrene environmental concentrations and urinary metabolites. Higher SCE rate (P<0.01) was observed in exposed workers than in controls. Besides, significant correlations were obtained for SCE rate with both environmental and internal exposure parameters (r=0.496, P<0.01 and r=0.511, P<0.01, respectively). Results from MN test and comet assay showed slight and non-significant increases related to the exposure. Our data seem to support previous studies reporting genotoxicity associated with occupational exposure to styrene, excluding the confounding influence of smoking, although caution must be taken in the interpretation of these results since the significance of an increase in SCE rate is still unclear.

Oxidative injury in V79 Chinese hamster cells: protective role of the superoxide dismutase mimetic MnTM-4-PyP.

Oxidative cell injury could be induced by different reactive oxygen species (ROS) operating in multiple pathways. The present work is focused on three different models of oxidative stress: the xanthine/xanthine oxidase system (XXO), an extracellular superoxide anion generator; tert-butylhydroperoxide (TBHP), an analogue of lipid hydroperoxides; and doxorubicin (Dox), an anticancer drug. Superoxide and peroxyl radicals, among other ROS, could be effectively scavenged by MnTM-4-PyP, a polyfunctional catalytic antioxidant. In this report, we have addressed the role of MnTM-4-PyP on the protection against the cytotoxicity induced by the three aforementioned oxidants. The effect of MnTM-4-PyP (0.1-100 microM) was evaluated in V79 fibroblasts using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide reduction and the crystal violet assays, as well as the mitotic index. Also, the generation of intracellular ROS was studied by the fluorescent probe dihydroethidium. MnTM-4-PyP has shown significant protective effects against the cytotoxicity of XXO and TBHP, increasing the cell viability in approximately 40% and reducing the intracellular level of ROS. However, no considerable protection occurred against Dox. The three oxidants caused a mitotic index reduction that was not altered by MnTM-4-PyP. In summary, MnTM-4-PyP appears to be a promising agent for the protection against oxidative injury. However, it has shown differential responses, reinforcing the need to study different experimental models for the adequate evaluation of its potentialities as a catalytic antioxidant.

Association of common variants in mismatch repair genes and breast cancer susceptibility: a multigene study.

BACKGROUND: MMR is responsible for the repair of base-base mismatches and insertion/deletion loops. Besides this, MMR is also associated with an anti-recombination function, suppressing homologous recombination. Losses of heterozygosity and/or microsatellite instability have been detected in a large number of skin samples from breast cancer patients, suggesting a potential role of MMR in breast cancer susceptibility. METHODS: We carried out a hospital-based case-control study in a Caucasian Portuguese population (287 cases and 547 controls) to estimate the susceptibility to non-familial breast cancer associated with some polymorphisms in mismatch repair genes (MSH3, MSH4, MSH6, MLH1, MLH3, PMS1 and MUTYH). RESULTS: Using unconditional logistic regression we found that MLH3 (L844P, G>A) polymorphism GA (Leu/Pro) and AA (Pro/Pro) genotypes were associated with a decreased risk: OR = 0.65 (0.45-0.95) (p = 0.03) and OR = 0.62 (0.41-0.94) (p = 0.03), respectively.Analysis of two-way SNP interaction effects on breast cancer revealed two potential associations to breast cancer susceptibility: MSH3 Ala1045Thr/MSH6 Gly39Glu - AA/TC [OR = 0.43 (0.21-0.83), p = 0.01] associated with a decreased risk; and MSH4 Ala97Thr/MLH3 Leu844Pro - AG/AA [OR = 2.35 (1.23-4.49), p = 0.01], GG/AA [OR = 2.11 (1.12-3,98), p = 0.02], and GG/AG [adjusted OR = 1.88 (1.12-3.15), p = 0.02] all associated with an increased risk for breast cancer. CONCLUSION: It is possible that some of these common variants in MMR genes contribute significantly to breast cancer susceptibility. However, further studies with a large sample size will be needed to support our results.

The role of GSTA2 polymorphisms and haplotypes in breast cancer susceptibility: a case-control study in the Portuguese population.

Glutathione-S-transferases (GSTs) are a super-family of phase II metabolizing enzymes that catalyse the detoxification of a large range of endogenous and exogenous toxic compounds, playing an important role in protecting cells against damage, through glutathione conjugation with electrophilic substances. Polymorphic variation in these enzymes that affect its activity seems to be related to individual susceptibility to various human diseases, including cancer. Of the GST super-family, the alpha class GSTs have commonly been described as one of the most versatile class, since it is responsible for detoxification of compounds such as bilirubin, bile acids and penicillin, thyroid and steroid hormones, allowing its solubilization and storage in the liver. Among the alpha class, GSTA1 and GSTA2 isoforms are the most widely expressed in human tissues. Additionally, these enzymes can catalyse conjugation of the nitrogen mustard group of alkylating anticancer drugs, some heterocyclic amines and alpha,beta-unsaturated aldehydes. Since some risk factors for increased breast cancer risk could be related to high production of reactive oxygen species during the metabolism of estrogens by catechol estrogens, or to the exposure to genotoxic compounds, and some of these toxic compounds are usually metabolized by GSTA2, we carried out a hospital based case-control study in a Caucasian Portuguese population (291 breast cancer patients without familiar history of breast cancer and 547 controls matched for age, sex and ethnicity) in order to evaluate the potential modifying role of three non-synonymous polymorphisms in the GSTA2 gene (P110S Ex 5+56C>T;, rs2234951; S112T Ex5+63G>C, rs2180314 and E210A Ex7+83A>C, rs6577) on the individual susceptibility to breast cancer. Our data show that the studied polymorphisms are in strong linkage disequilibrium, but no association was observed between individual GSTA2 polymorphisms and haplotypes and individual susceptibility to breast cancer.

Cytotoxicity and chromosomal aberrations induced by acrylamide in V79 cells: role of glutathione modulators.

Acrylamide (AA) is a suspected human carcinogen found to be generated during the heating of carbohydrate-rich foodstuffs. AA exhibits 'Michael-type' reactivity towards reduced glutathione (GSH), resulting in vivo in the urinary excretion of mercapturic acid conjugates. GSH is a key factor for mammalian cell homeostasis, with diverse functions that include, among others, the conjugation of electrophilic compounds and the detoxification of products generated by oxidative stress. Therefore, studies focusing on the modulation of GSH are of great importance for the understanding of the mechanisms of AA-induced toxicity. This report addresses this issue by analyzing cytotoxicity (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) reduction assay) and clastogenicity (chromosomal aberrations) as endpoints in V79 cells after exposure to AA. The experiments described herein include the evaluation of the effect of buthionine sulfoximine (BSO), an effective inhibitor of GSH synthesis, GSH-monoethyl ester (GSH-EE), a compound that is taken up by cells and intracellularly hydrolysed to GSH, and also GSH exogenously added to culture medium. Pre-treatment with BSO increased the cytotoxicity and the frequency of aberrant cells excluding gaps (ACEG) induced by AA. While pre-treatment with GSH-EE did not modify the cytotoxicity or the frequency of ACEG induced by AA, co-treatment with AA and GSH decreased both parameters, rendering the cells less prone to the toxic effects of AA. In vitro studies in a cell-free system, using monochlorobimane (MCB), a fluorescent probe for GSH, were also performed in order to evaluate the role of AA in GSH depletion. The results show that spontaneous conjugation of AA with GSH in the extracellular medium is involved in the protection given by GSH. In summary, these results reinforce the role of GSH in the modulation of the cytotoxic and clastogenic effects induced by AA, which may be relevant in an in vivo exposure scenario.

Combined clot fragmentation and aspiration in patients with acute pulmonary embolism.

BACKGROUND: Massive angiographic pulmonary embolism (PE) with right ventricular dysfunction (RVD) is associated with a high early mortality rate. The therapeutic alternatives for this condition include thrombolysis, surgical embolectomy, or percutaneous mechanical thrombectomy (PMT). We describe our experience using PMT in patients with massive PE and RVD with unsuccessful thrombolysis, increased bleeding risk, or major contraindications for thrombolytic therapy. METHODS: Clinical, hemodynamic, and angiographic parameters prior to and following PMT were evaluated. Our primary objective was to describe the incidence of in-hospital cardiovascular death, and of major and minor complications. Mid-term outcomes included analysis of occurrence of cardiovascular death, recurrent pulmonary embolism, change of New York Heart Association functional class, and hospital readmission. RESULTS: From July 2004 to May 2007, 69 patients were referred to the cardiac catheterization laboratory with a diagnosis of acute PE, 18 of whom met the criteria for massive PE and are the subject of this study. All patients underwent thrombus fragmentation using a pigtail catheter that was complemented in 13 patients with thrombus aspiration. A percutaneous thrombectomy device (Aspirex; Straub Medical; Wangs, Switzerland) was used in 11 patients. Hemodynamic, angiographic, and blood oxygenation parameters improved after the procedure. A significant increase was observed for systolic systemic BP (74.3+/-7.5 mm Hg vs 89.4+/-11.3 mm Hg, p=0.001) [mean+/-SD], as was a decrease in mean pulmonary artery pressure (37.1+/-8.5 mm Hg vs 32.3+/-10.5 mm Hg , p=0.0001). The in-hospital major complications rate was 11.1%; one patient died from refractory shock, and one patient had intracerebral hemorrhage with minor neurologic sequelae. No cardiovascular deaths or recurrent pulmonary thromboembolism were documented during clinical follow-up (12.3+/-9.4 months). CONCLUSIONS: In patients with massive PE, RVD and major contraindications to thrombolytic therapy, increased bleeding risk, failed thrombolysis, or unavailable surgical thrombectomy, PMT appears to be a useful therapeutic alternative.