Relationship between ambient air pollution and DNA damage in Polish mothers and newborns

Industrialized regions in Poland are characterized by high ambient pollution, including polycyclic aromatic hydrocarbons (PAHs) from coal burning for industry and home heating. In experimental bioassays, certain PAHs are transplacental carcinogens and developmental toxicants. Biologic markers can facilitate evaluation of effects of environmental PAHs on the developing infant. We measured the amount of PAHs bound to DNA (PAH-DNA adducts) in maternal and umbilical white blood cells. The cohort consisted of 70 mothers and newborns from Krakow, Poland, an industrialized city with elevated air pollution. Modulation of adduct levels by genotypes previously linked to risk of lung cancer, specifically glutathione S-transferase MI (GSTM1) and cytochrome P4501A1 (CYP1A1) Msp restriction fragment length polymorphism (RFLP), was also investigated. There was a dose-related increase in maternal and newborn adduct levels with ambient pollution at the women's place of residence among subjects who were not employed away from home (p < or = 0.05). Maternal smoking (active and passive) significantly increased maternal (p < or = 0.01) but not newborn adduct levels. Neither CYP1A1 Msp nor GSTM1 polymorphisms was associated with maternal adducts. However, adducts were significantly higher in newborns heterozygous or homozygous for the CYP1A1 Msp RFLP compared to newborns without the RFLP (p = 0.04). Results indicate that PAH-induced DNA damage in mothers and newborns is increased by ambient air pollution. In the fetus, this damage appears to be enhanced by the CYP1A1 Mspl polymorphism.

Cigarette smoking, N-acetyltransferases 1 and 2, and breast cancer risk

To examine the effects of smoking and N-acetylation genetics on breast cancer risk, we analyzed data from an ongoing, population-based, case-control study of invasive breast cancer in North Carolina. The study population consisted of 498 cases and 473 controls, with approximately equal numbers of African-American and white women, and women under the age of 50 and age 50 years or older. Among premenopausal women, there was no association between current smoking [odds ratio (OR), 0.9; 95% confidence interval (CI), 0.5-1.5] or past smoking (OR, 1.0; 95% CI, 0.6-1.6) and breast cancer risk. Among postmenopausal women, there was also no association with current smoking (OR, 1.2; 95% CI, 0.7-2.0); however, a small increase in risk was observed for past smoking (OR, 1.5; 95% CI, 1.0-2.4). For postmenopausal women who smoked in the past, ORs and 95% CIs were 3.4 (1.4-8.1) for smoking within the past 3 years, 3.0 (1.3-6.7) for smoking 4-9 years ago, and 0.6 (0.3-1.4) for smoking 10-19 years ago. Neither N-acetyltransferase 1 (NAT1) nor N-acetyltransferase 2 (NAT2) genotype alone was associated with increased breast cancer risk. There was little evidence for modification of smoking effects according to genotype, except among postmenopausal women. Among postmenopausal women, ORs for smoking within the past 3 years were greater for women with the NAT1*10 genotype (OR, 9.0; 95% CI, 1.9-41.8) than NAT1-non*10 (OR, 2.5; 95% CI, 0.9-7.2) and greater for NAT2-rapid genotype (OR, 7.4; 95% CI, 1.6-32.6) than NAT2-slow (OR, 2.8; 95% CI, 0.4-8.0). Future studies of NAT genotypes and breast cancer should investigate the effects of environmental tobacco smoke, diet, and other exposures.

Song learning and vocal tradition in Nuttall's white-crowned sparrows

We investigated song sharing and dispersion of song types in the wild in a colour-marked population of the non-migratory Nuttall's white-crowned sparrow, Zonotrichia leucophrys nuttalli. The songs of fathers, their male progeny (sons), and the neighbours of the sons at recruitment sites were analysed spectrographically and compared qualitatively and quantitatively. To determine whether a son's song more closely matched that of his father or a neighbour at the site settled, we subjected frequency and temporal characteristics of songs within each father-son-neighbour triad to multivariate cluster analysis. The songs of 14 of 16 sons clustered with their neighbours' rather than their fathers' songs, confirming that song matching of neighbours is an integral component of territory settlement by juveniles. Principal components analysis of frequency and temporal measurements of song within a dialectal area show that songs group into neighbourhoods and are non-randomly distributed. Multivariate analysis suggests that sons may entrain on frequency and temporal characteristics of a neighbour's song without matching phrases or complex syllables. Implications for models of instructive versus selective learning are discussed. The timing of closure of the sensitive phase, the length of the silent interval between the sensory phase and plastic song stage, and the time to song crystallization remain open questions in song ontogeny. Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.

Transitional cell metaplasia of the cervix: a newly described entity in cervicovaginal smears

Transitional cell metaplasia (TCM) of the cervix is rarely reported in the pathology literature. To our knowledge, no case reports describing TCM in cervicovaginal smears exist. We report the cytologic features of TCM and compare them with squamous-cell carcinoma in situ (CIS), tubal metaplasia (TM), and atrophy. One hundred twenty-seven cervicovaginal smears from 31 patients with histologically proven cervical TCM were reviewed: seven smears (five patients) showed TCM. Five smears each of CIS, TM, and atrophy were evaluated as to architecture, nuclear features, nuclear to cytoplasmic ratios, and cytoplasmic haloes for comparison to TCM. The features that characterize TCM and allow its distinction from CIS, TM, and atrophy include cohesive groups of streaming spindled nuclei with haloes, grooves, tapered ends, and wrinkled contours.

Human glutathione S-transferase P1 polymorphisms: relationship to lung tissue enzyme activity and population frequency distribution

The association between glutathione S-transferase (GST) activity as measured by 1-chloro-2,4-dinitrobenzene (CDNB) conjugation and genotype at exon 5 and exon 6 of the human GSTP1 gene was investigated in normal lung tissue obtained from 34 surgical patients. These samples were genotyped for previously identified polymorphisms in exon 5 (Ile105Val) and exon 6 (Ala114Val) by PCR-RFLP and direct sequencing. GST enzyme activity was significantly lower among individuals with the 105 Val allele. Homozygous Ile/Ile samples (n = 18) had a mean cytosolic CDNB conjugating activity of 74.9 +/- 3.8 nmol/mg per min; heterozygotes (n = 13) had a mean specific activity of 62.1 +/- 4.2 nmol/mg per min and homozygous Val/Val (n = 3) had a mean specific activity of 52.5 +/- 4.5 nmol/mg per min. The CDNB conjugating activity measured for the Ile/Ile genotype group was significantly different from that observed in the Ile/Val group (P = 0.03), and from Ile/Val and Val/Val genotypes combined (P = 0.009). Mean GST activity values were consistently lower in individuals with genotypes containing the 105 valine allele, regardless of smoking exposure. Genotypes at codon 114 were also assessed but the mean GST activity was not significantly lower in individuals with the 114 valine allele. A new haplotype, present in two samples who were homozygous 105Ile and had a 114Val, was identified and proposed as GSTP1*D. Frequencies of the exon 5 and exon 6 polymorphisms were determined in samples obtained from European-Americans, African-Americans and Taiwanese. The differences observed were highly significant suggesting the possibility of GSTP1 genotype-associated, ethnic differences in cancer susceptibility and chemotherapeutic response.

Identification and characterization of variant alleles of human acetyltransferase NAT1 with defective function using p-aminosalicylate as an in-vivo and in-vitro probe

Although several variant alleles at the human NAT1 gene locus have been reported, their relationship to phenotypic variations in NAT1 function remains unclear. We have used in-vivo and invitro phenotyping tests, along with PCR-based cloning and heterologous expression, to investigate the extent of variation in NAT1 function and to characterize novel allelic variants at the NAT1 gene locus. The NAT1-selective substrate p-aminosalicylic acid (PAS) was used as a probe for NAT1 function. In-vivo PAS acetylation rates were estimated by determining the ratio of PAS to N-acetylated PAS (AcPAS) in urine and plasma following the oral ingestion of Nemasol Sodium. Excluding outliers, a 65-fold variation in the urinary AcPAS:PAS ratio was observed (n = 144), while a 5.6-fold variation in the plasma AcPAS:PAS ratio was seen in a subset (n = 19) of this sample. Urinary and plasma ratios correlated moderately (r = 0.74, p < 0.0005). One individual (case 244) had a marked impairment of PAS N-acetylation, with 10-fold lower urinary and plasma AcPAS:PAS ratios compared with other subjects. Biochemical investigations in whole blood lysates from case 244 suggested a NAT1 kinetic defect, with a 20-fold increased apparent K(m) for PAS and a 90-fold decreased Vmax for AcPAS formation. We subcloned, sequenced and expressed the protein-coding regions of the NAT1 alleles from case 244 and from seven other selected probands. Sequence analysis revealed the presence of two new variant alleles, designated as NAT1 x 14 and NAT1 x 15, in case 244, as well as one variant, NAT1 x 11, which has been observed in previous investigations. NAT1 x 14 contained a missense mutation (G560-->A) that is predicted to change a single amino acid (Arg187-->Gln), as well as two 3' non-coding region mutations (T1088-->A and C1095-->A) that have previously been observed in the NAT1 x 10 allelic variant. NAT1 x 15 had a single nonsense mutation (C559-->T; Arg187-->stop) and, thus, encodes a truncated protein. The activity of recombinant NAT1 14 mirrored the defective enzyme function in whole blood lysates from case 244, while NAT1 15 was completely inactive. Expressed NAT1 11, on the other hand, had identical activity to the wild type NAT1 4 allele, suggesting that the coding region mutations in this variant are functionally silent. The frequencies of NAT1 x 11, NAT1 x 14 and NAT1 x 15 were 0.021, 0.028 and 0.014 (n = 288 alleles), respectively, suggesting that they are relatively rare in our predominantly Caucasian sample.

A one centimorgan deletion unit on chromosome Xq12 is commonly lost in borderline and invasive epithelial ovarian tumors

We have used polymerase chain reaction (PCR) amplification of tandem repeats to study the pattern of allelic loss on chromosome X11.2-q12 in borderline and invasive epithelial ovarian tumors. Using eight microsatellite markers spanning Xq11.2-q12, 41 borderline and 65 invasive ovarian tumors, together with their corresponding normal tissues, were analysed. The highest percentage of loss of heterozygosity (LOH) was observed at the DXS1194 locus in borderline tumors (four of 16 informative cases, 25%) and at the androgen receptor (AR) locus in invasive epithelial ovarian tumors (18 of 47 informative cases, 38%). X chromosome activation studies performed in cases with LOH at the AR locus showed that the allelic loss at the AR locus is not confined to the inactive allele. A one centimorgan region including the AR locus and flanked by the primers DXS1161 and PGK1P1 was identified as the smallest common loss region in both borderline and invasive epithelial ovarian tumors.

An association between the allele coding for a low activity variant of catechol-O-methyltransferase and the risk for breast cancer

Mounting evidence suggests that catechol metabolites of estradiol may contribute to the development of estrogen-induced cancers. O-Methylation, catalyzed by catechol-O-methyltransferase (COMT), inactivates catechol estrogens. COMT is polymorphic in the human population, with 25% of Caucasians being homozygous for a low activity allele of the enzyme (COMT(LL)). We hypothesized that low activity COMT may be a risk factor for human breast cancer and designed a PCR-based RFLP assay to determine COMT genotype in a cohort of 112 matched, nested case-control samples. In the total study population, the odds ratios for the association of breast cancer risk with COMT(HL) and COMT(LL) genotypes were 1.30 [confidence interval (CI), 0.66-2.58] and 1.45 (CI, 0.69-3.07), respectively. Postmenopausal COMT(LL) women had a greater than 2-fold increased risk of developing breast cancer [odds ratio (OR), 2.18; CI, 0.93-5.11]. The association of COMT(LL) with the development of postmenopausal breast cancer was stronger and statistically significant in those women with a body mass index >24.47 kg/m2 (OR, 3.58; CI, 1.07-11.98). When COMT(LL) was combined with either glutathione S-transferase (GST) M1 null or with GSTP1 Ile-105-Val/Val-105-Val (intermediate/low activity, respectively) genotypes, the risk for developing postmenopausal breast cancer was also significantly increased. Our findings suggest that the allele encoding low activity COMT may be an important contributor to the postmenopausal development of breast cancer in certain women.

Acidic urine pH is associated with elevated levels of free urinary benzidine and N-acetylbenzidine and urothelial cell DNA adducts in exposed workers

We evaluated the influence of urine pH on the proportion of urinary benzidine (BZ) and N-acetylbenzidine present in the free, unconjugated state and on exfoliated urothelial cell DNA adduct levels in 32 workers exposed to BZ in India. Postworkshift urine pH was inversely correlated with the proportions of BZ (r = -0.78; P < 0.0001) and N-acetylbenzidine (r = -0.67; P < 0.0001) present as free compounds. Furthermore, the average of each subject's pre- and postworkshift urine pH was negatively associated with the predominant urothelial DNA adduct (P = 0.0037, adjusted for urinary BZ and metabolites), which has been shown to cochromatograph with a N-(3'-phosphodeoxyguanosin-8-yl)-N'-acetylbenzidine adduct standard. Controlling for internal dose, individuals with urine pH < 6 had 10-fold higher DNA adduct levels compared to subjects with urine pH > or = 7. As reported previously, polymorphisms in NAT1, NAT2, and GSTM1 had no impact on DNA adduct levels. This is the first study to demonstrate that urine pH has a strong influence on the presence of free urinary aromatic amine compounds and on urothelial cell DNA adduct levels in exposed humans. Because there is evidence that acidic urine has a similar influence on aromatic amines derived from cigarette smoke, urine pH, which is influenced by diet, may be an important susceptibility factor for bladder cancer caused by tobacco in the general population.

Pilot study of free and conjugated urinary mutagenicity during consumption of pan-fried meats: possible modulation by cruciferous vegetables, glutathione S-transferase-M1, and N-acetyltransferase-2

Epidemiological and experimental evidence indicates that consumption of fried meats in conjunction with certain genotypes of phase I and II metabolism genes poses an elevated risk for colorectal cancer. Parallel to this, the consumption of cruciferous vegetables is associated with a reduced risk of colon cancer. Therefore, we designed a 6-week pilot feeding study to evaluate the effect of these variables on urinary mutagenicity, which is a biomarker associated with fried-meat consumption. Eight subjects were fed fried meats daily for six weeks; four ate cruciferous vegetables, and four ate non-cruciferous vegetables. Urinary mutagenicity was evaluated in the presence of S9 in strain YG1024 of Salmonella, which is a frameshift strain that overproduces acetyltransferase. C18/methanol extracts of 24-h urines collected once each week were tested unhydrolyzed (free mutagenicity) and hydrolyzed (total mutagenicity); the difference between the two was the conjugated mutagenicity. Although not significant, the levels of conjugated urinary mutagenicity doubled among crucifera consumers and decreased to 30% of the initial levels among non-crucifera consumers, suggesting the possibility that crucifera may enhance the level of conjugated urinary mutagenicity resulting from consumption of fried meats. Such an effect would be consistent with the documented ability of cruciferous vegetables to induce phase II enzymes. The NAT2 rapid phenotype was significantly associated with approximately 2-fold increases in conjugated (p = 0.05) and total (p = 0.004) urinary mutagenicity relative to NAT2 slow subjects, consistent with the elevated risk confirmed by the NAT2 rapid phenotype for colorectal cancer among meat consumers. An approximately 2-fold increase in urinary mutagenicity among the GSTM1- subjects relative to the GSTM1+ subjects approached significance for free (p = 0.18) and total (p = 0.13) urinary mutagenicity. This is the first report on (a) the mutagenicity of hydrolyzed urine, which was consistently more mutagenic than unhydrolyzed urine; (b) the potential enhancement of conjugated urinary mutagenicity by crucifera; and (c) the association of the rapid NAT2 and possibly the GSTM1- phenotype with elevated levels of fried meat-associated urinary mutagenicity.

Genetic polymorphisms in human drug metabolic enzymes

Results obtained from both epidemiologic studies and experimental animal model systems have shown a wide range of phenotypic variation in the ability of individuals to metabolize drugs and environmental chemicals. Several studies have noted correlations between specific metabolic phenotypes and the incidence of disease, suggesting that certain allelic forms of drug metabolic enzymes can render the individual either more sensitive or resistant to the toxic or therapeutic effects of exogenous drugs and chemicals. While some of this variation can be attributed to different environmental exposures, it has become clear that genetic factors also play an important role in determining the response of the individual organism to exogenous agents. Recent advances in molecular biological techniques have begun to allow scientists to correlate observed phenotypic differences with the actual differences in genetic sequence at the gene level. This has allowed a correlation between gene structure and function, thus providing a mechanistic basis to explain the interaction between genetic background and individual response to environmental exposures. Results presented at this symposium discussed how genetic polymorphisms for both Phase I and Phase II metabolic enzymes in the human population modulate the response to environmental toxicants.

V region gene analysis of human IgM hybridoma monoclonal anti-Sm antibodies

Anti-Sm antibodies although highly specific for systemic lupus erythematosus can only be found in 10-25% of lupus patients and lupus-prone MRL/lpr mice. Molecular studies of these autoantibodies from mice have suggested that the anti-Sm response is Ag driven, its expression is controlled by stochastic events and may originate from the same B cell precursors as anti-DNA antibodies. However, relatively little information regarding the molecular characteristics of anti-Sm antibodies in man has been reported. We studied the V region genes of three IgM hybridoma monoclonal antibodies (BUD 45.12.8, BUD 114.4.11 and BUD 94.91.8) which were selected for Sm reactivity and derived from B cells of a healthy child. Two of these antibodies BUD 45.12.8 and BUD 114.4.11 also-reacted with ssDNA, while the third (BUD 94.91.8) did not. Each of these anti-Sm/ RNP antibodies was encoded by different and predominantly unmutated Ig heavy chain germline genes (BUD 45.12.8 by VH3-23, DXP4 and JH4b; BUD 94.91.8 by VH3-33, D21-9 and JH6b; BUD 114.4.11 by VH1-2, DK1 or DM1 or unknown D and JH4b) and light chain genes (BUD 45.12.8 by Humkv325 and JK2; BUD 94.91.8 by hsiggll150 (lambda IIIb) and J lambda 2/3; BUD 114.4.11 by Humk18 and JK3). Many of these genes are also used by antibodies with other specificities including DNA. The two anti-Sm antibodies which also bound ssDNA shared an overall V region net positive charge, while the third antibody without ssDNA reactivity carried a negative V region net charge. These findings demonstrate that (1) normal individuals have the genetic potential to generate autoantibodies to Sm/RNP; (2) acquisition of Sm/RNP binding is not dependent on somatic mutations and (3) some human B cell clones exhibit specificity for Sm and ssDNA.

Production of human normal adult and fetal hemoglobins in Escherichia coli

A hemoglobin expression system in Escherichia coli is described. In order to produce authentic human hemoglobin, we need to co-express both methionine aminopeptidase and globin genes under the control of a strong promoter. We have constructed three plasmids, pHE2, pHE4 and pHE7, for the expression of human normal adult hemoglobin and a plasmid, pHE9, for the expression of human fetal hemoglobin, in high yields. The globin genes can be derived from either synthetic genes or human globin cDNAs. The extra amino-terminal methionine residues of the expressed globins can be removed by the co-expressed methionine aminopeptidase. The heme is inserted correctly into the expressed alpha-globin from our expression plasmids. A fraction (approximately 25%) of the heme is not inserted correctly into the expressed beta- or gamma-globin. However, the incorrectly inserted hemes can be converted into the correct conformation by carrying out a simple oxidation-reduction process on the purified hemoglobin molecule. We have investigated the functional properties of the expressed hemoglobins by measuring their oxygen-binding properties and their structural features by obtaining their 1H-NMR spectra. Our results show that authentic human normal adult and fetal hemoglobins can be produced from our expression plasmids in E. coli and in high yields. Our expression system allows us to design and to produce any recombinant hemoglobins needed for our research on the structure-function relationship in hemoglobin.

Identification of a 1300 kilobase deletion unit on chromosome 7q31.3 in invasive epithelial ovarian carcinomas

We have used polymerase chain reaction (PCR) amplification of tandem repeats to study the pattern of allelic loss on chromosome 7q31 in invasive epithelial ovarian carcinomas and borderline ovarian tumors. Using 13 primer sets spanning loci from 7q31 to 7q32, 16 borderline and 54 invasive ovarian tumor tissue, together with their corresponding normal tissue, were analysed. Invasive epithelial ovarian tumors demonstrated loss of heterozygosity (LOH) at one or more loci on 7q in 32 of 54 cases (59%). The invasive epithelial ovarian tumors demonstrated the highest percentage of LOH at the loci D7S643 (20 of 40 informative cases, 50%) and GATA44F09 (18 of 42 informative cases, 43%). In contrary, only one borderline ovarian tumor showed LOH at one locus (GATA44F09, one of 14 informative cases, 7%). Our results display a sharp contrast in the pattern of LOH between invasive and borderline ovarian tumors suggesting that allelic loss at chromosome 7q31.3 may be involved in the development and progression of invasive epithelial ovarian tumors but not borderline ovarian tumors. Further analysis of the deletion map for the invasive epithelial ovarian tumors showed two regions likely to harbor ovarian tumor suppressor genes including a novel 1300 kilobase common loss region flanked by GATA44F09 and D7S643.

Dichloromethane metabolism to formaldehyde and reaction of formaldehyde with nucleic acids in hepatocytes of rodents and humans with and without glutathione S-transferase T1 and M1 genes

Metabolism of dichloromethane (DCM) to formaldehyde (HCHO) via a glutathione S-transferase (GST) pathway is thought to be required for its carcinogenic effects in B6C3F1 mice. In humans, this reaction is catalyzed primarily by the protein product of the gene GSTT1, a member of the Theta class of GST, and perhaps to a small extent by the protein product of the gene GSTM1. Humans are polymorphic with respect to both genes. Since HCHO may bind to both DNA and RNA forming DNA-protein crosslinks (DPX) and RNA-formaldehyde adducts (RFA), respectively, these products were determined in isolated hepatocytes from B6C3F1 mice, F344 rats, Syrian golden hamsters, and humans to compare species with respect to the production of HCHO from DCM and its reaction with nucleic acids. Only mouse hepatocytes formed detectable amounts of DPX, the quantities of which corresponded well with quantities of DPX formed in the livers of mice exposed to DCM in vivo [Casanova, M., Conolly, R.B., and Heck, H. d'A. (1996). Fundam. Appl. Toxicol. 31, 103-116]. Hepatocytes from all rodent species and from humans with functional GSTT1 and GSTM1 genes formed RFA. No RFA were detected in human cells lacking these genes. Yields of RFA in hepatocytes of mice were 4-fold higher than in those of rats, 7-fold higher than in those of humans, and 14-fold higher than in those of hamsters. The RFA:DPX ratio in mouse hepatocytes incubated with DCM was approximately 9.0 +/- 1.4, but it was 1.1 +/- 0.3 when HCHO was added directly to the medium, indicating that HCHO generated internally from DCM is not equivalent to that added externally to cells and that it may occupy separate pools. DPX were not detected in human hepatocytes even at concentrations equivalent to an in vivo exposure of 10,000 ppm; however, the possibility that very small amounts of DPX were produced from DCM cannot be excluded, since HCHO was formed in human cells. Maximal amounts of DPXliver that might be formed in humans were predicted from the amounts in mice and the relative amounts of RFA in hepatocytes of both species. With predicted DPXliver as the dosimeter, the unit risk, the upper 95% confidence limit on the cancer risk, and the margin of exposure were calculated at several concentrations using the linearized multistage and benchmark dose methods. Since the actual delivered dose is smaller than that predicted, the results suggest that DCM poses at most a very low risk of liver cancer to humans.

Transitional cell metaplasia of the uterine cervix and vagina: an underrecognized lesion that may be confused with high-grade dysplasia. A report of 59 cases

Sixty-three examples of transitional cell metaplasia of the cervix or vagina from patients 50 to 84 (average 67.6) years of age are described. Fifty-seven of the 59 patients were postmenopausal and two perimenopausal. Only four patients were documented to have received hormonal therapy. The lesion was an incidental microscopic finding in all patients and was found in 29 hysterectomy specimens, 18 endocervical or endometrial curettage specimens, 11 cervical biopsy or cone biopsy specimens, and five vaginal biopsy specimens. The sites involved by transitional cell metaplasia were the exocervix (n = 14), transformation zone (n = 33), vagina (n = 10), or a combination (n = 4). The cervical and vaginal specimens most commonly showed involvement of the surface epithelium by transitional cell metaplasia. Other transitional cell patterns were isolated stromal nests (n = 9) and invagination of surface epithelium into the underlying stroma (n = 2). The typical appearance of transitional cell metaplasia was a hyperplastic epithelium with lack of maturation, consisting of spindled nuclei with tapered ends and frequent longitudinal nuclear grooves. The nuclei were typically oriented vertically in the deeper layers, and horizontally with a streaming pattern superficially. The cells had low nuclear to cytoplasmic ratios, perinuclear halos, and absent to rare mitotic figures. Mild to moderate atypia was seen in only two cases. Many of the cases could have been confused with squamous dysplasia due to the lack of apparent maturation. However, in most cases, attention to cytologic detail disclosed the typical features of transitional cell metaplasia. This process, usually seen in older women, has not been emphasized and can be overdiagnosed as dysplasia, leading to unnecessary treatment.

Isolated straight sinus and deep cerebral venous thrombosis: successful treatment with local infusion of urokinase. Case report

A 23-year-old woman presented with headache and progressive lethargy. The diagnosis of isolated thrombosis of the straight sinus and of the deep cerebral venous system was established using cranial computerized tomography, magnetic resonance imaging, phase-contrast magnetic resonance venography, and cerebral angiography. Because of the rapid deterioration in the patient's clinical condition, the authors used direct transcatheter infusion of urokinase into the straight sinus. This treatment resulted in a successful outcome.

Contribution of genetic and nutritional factors to DNA damage in heavy smokers

Prior epidemiological evidence suggests that genes controlling the metabolism of carcinogens and antioxidant/nutritional status are associated with lung cancer risk, possibly through their ability to modulate DNA damage by carcinogens. We performed a cross-sectional analysis of 159 heavy smokers from a cohort of subjects enrolled in a smoking cessation program. A total of 159 blood samples were analyzed to determine the relative contributions of genetic polymorphisms [CYP1A1 MspI and exon 7 and glutathione S-transferase M1 (GSTM1)] and plasma micronutrients to polycyclic aromatic hydrocarbon-DNA (PAH-DNA) adduct levels. DNA damage in smokers was affected by genetic polymorphisms and nutritional status. Smokers with the CYP1A1 exon 7 valine polymorphism had significantly higher (2-fold, P < or = 0.03) levels of DNA damage than those without. In parallel models, PAH-DNA adducts were inversely associated with plasma levels of retinol (beta = -0.93, P = 0.01), beta-carotene (beta = -0.18, P = 0.09), and alpha-tocopherol (beta = -0.28, P = 0.21) in 159 subjects. The association between smoking-adjusted plasma beta-carotene levels and DNA damage was only significant in those subjects lacking the GSTM1 detoxification gene (beta = -0.30, P = 0.05, n = 75). There was a statistical interaction between beta-carotene and alpha-tocopherol; when beta-carotene was low, alpha-tocopherol had a significant protective effect (beta = -0.78, P = 0.04) on adducts, but not when beta-carotene was high (beta = -0.16, P = 0.57). Plasma alpha-tocopherol was significantly correlated with beta-carotene (r = 0.36, P = 0.0005) and less strongly with retinol (r = 0.20, P = 0.0005). These results suggest that several micronutrients may act in concert to protect against DNA damage and highlight the importance of assessing overall antioxidant status. In conclusion, a subset of smokers may be at increased risk of DNA damage and possibly lung cancer due to the combined effect of low plasma micronutrients and genetic susceptibility factors. The use of biological markers to assess efficacy of interventions and to study mechanisms of micronutrients is timely given the current debate regarding the use of chemopreventive agents in high risk populations.

Microsomal epoxide hydrolase polymorphism as a risk factor for ovarian cancer

Microsomal epoxide hydrolase (EPHX) is one of many enzymes involved in the metabolism of endogenous and exogenous toxicants. Polymorphic forms of the human EPHX gene have been described that vary in enzymatic activity, and one, Tyr113His, has been associated with hepatocellular carcinoma susceptibility. We demonstrated that EPHX was highly expressed in the human ovary, and investigated whether specific EPHX genotypes are associated with ovarian cancer susceptibility. Seventy-three Caucasian patients with ovarian cancer and 75 Caucasian-female controls without cancer were genotyped for the Tyr113His polymorphism by a polymerase chain reaction-restriction fragment length polymorphism assay. The frequency of the homozygous high-activity genotype was 41% in the control population and 64% in the ovarian cancer patients. The odds ratio for ovarian cancer with this genotype was 2.6 (95% confidence interval 1.3, 5.0; P < 0.01). The increased ovarian cancer risk associated with the high-activity genotype could reflect differences in metabolic activation of endogenous or exogenous carcinogens.

Microsomal epoxide hydrolase polymorphism as a risk factor for ovarian cancer

Microsomal epoxide hydrolase (EPHX) is one of many enzymes involved in the metabolism of endogenous and exogenous toxicants. Polymorphic forms of the human EPHX gene have been described that vary in enzymatic activity, and one, Tyr113His, has been associated with hepatocellular carcinoma susceptibility. We demonstrated that EPHX was highly expressed in the human ovary, and investigated whether specific EPHX genotypes are associated with ovarian cancer susceptibility. Seventy-three Caucasian patients with ovarian cancer and 75 Caucasian-female controls without cancer were genotyped for the Tyr113His polymorphism by a polymerase chain reaction-restriction fragment length polymorphism assay. The frequency of the homozygous high-activity genotype was 41% in the control population and 64% in the ovarian cancer patients. The odds ratio for ovarian cancer with this genotype was 2.6 (95% confidence interval 1.3, 5.0; P < 0.01). The increased ovarian cancer risk associated with the high-activity genotype could reflect differences in metabolic activation of endogenous or exogenous carcinogens.

The glutathione S-transferase M1 (GSTM1) null genotype and benzidine-associated bladder cancer, urine mutagenicity, and exfoliated urothelial cell DNA adducts

Multiple studies in the general population have suggested that subjects with the glutathione S-transferase M1 (GSTM1)-null genotype, who lack functional GSTM1, are at higher risk for bladder cancer. To evaluate the impact of the GSTM1-null genotype on bladder cancer caused by occupational exposure to benzidine and to determine its influence on benzidine metabolism, we carried out three complementary investigations: a case-control study of bladder cancer among workers previously exposed to benzidine in China, a cross-sectional study of urothelial cell DNA adducts and urinary mutagenicity in workers currently exposed to benzidine in India, and a laboratory study of the ability of human GSTM1 to conjugate benzidine and its known metabolites in vitro. There was no overall increase in bladder cancer risk for the GSTM1-null genotype among 38 bladder cancer cases and 43 controls (odds ratio, 1.0; 95% confidence interval, 0.4-2.7), although there was some indication that highly exposed workers with the GSTM1-null genotype were at greater risk of bladder cancer compared to similarly exposed workers without this allele. However, the GSTM1 genotype had no impact on urothelial cell DNA adduct and urinary mutagenicity levels in workers currently exposed to benzidine. Furthermore, human GSTM1 did not conjugate benzidine or its metabolites. These results led us to conclude that the GSTM1-null genotype does not have an impact on bladder cancer caused by benzidine, providing a contrast to its association with elevated bladder cancer risk in the general population.