A second locus for familial high myopia maps to chromosome 12q

Myopia, or nearsightedness, is the most common eye disorder worldwide. "Pathologic" high myopia, or myopia of <=-6.00 diopters, predisposes individuals to retinal detachment, macular degeneration, cataract, or glaucoma. A locus for autosomal dominant pathologic high myopia has been mapped to 18p11.31. We now report significant linkage of high myopia to a second locus at the 12q21-23 region in a large German/Italian family. The family had no clinical evidence of connective-tissue abnormalities or glaucoma. The average age at diagnosis of myopia was 5.9 years. The average spherical-component refractive error for the affected individuals was -9.47 diopters. Markers flanking or intragenic to the genes for the 18p locus, Stickler syndromes type I and II (12q13.1-q13.3 and 6p21.3), Marfan syndrome (15q21.1), and juvenile glaucoma (chromosome 1q21-q31) showed no linkage to the myopia in this family. The maximum LOD score with two-point linkage analysis in this pedigree was 3.85 at a recombination fraction of .0010, for markers D12S1706 and D12S327. Recombination events identified markers D12S1684 and D12S1605 as flanking markers that define a 30.1-cM interval on chromosome 12q21-23, for the second myopia gene. These results confirm genetic heterogeneity of myopia. The identification of this gene may provide insight into the pathophysiology of myopia and eye development.

Canadian Bardet-Biedl syndrome family reduces the critical region of BBS3 (3p) and presents with a variable phenotype

There are at least five distinct Bardet-Biedl syndrome (BBS) loci, four of which have been mapped: 11q (BBS1), 16q (BBS2), 3p (BBS3), and 15q (BBS4). A comparative study of the three Arab-Bedouin kindreds used to map the BBS2, BBS3, and BBS4 loci suggests that the variability in the number and severity of clinical manifestations, particularly the pattern of polydactyly, reflects chromosome-specific subtypes of BBS [Carmi et al., 1995a; Am J Med Genet 59:199-203]. We describe a Newfoundland kindred of northern European descent and confirm the initial finding of a BBS locus on chromosome 3. However, the "BBS3 phenotype," which includes polydactyly of all four limbs and a progression to morbid obesity, was not observed. Rather, four of the five BBS patients in this family had polydactyly restricted to their feet. The obesity in these patients was reversible with caloric restriction and/or exercise. Mental retardation has been considered a major symptom of BBS. However, formal IQ testing shows that these patients are of average intelligence. Haplotype analysis reduces the BBS3 critical region to a 6-cM interval between D3S1595-D3S1753.

Polycyclic aromatic hydrocarbon-DNA adducts in human placenta and modulation by CYP1A1 induction and genotype

This study investigated the relationship in human placenta between polycyclic aromatic hydrocabon (PAH)-DNA adduct levels and two biomarkers of cytochrome P4501A1 (CYP1A1): gene induction evidenced by CYP1A1 mRNA, and a genetic polymorphism, the CYP1A1 MspI RFLP. CYP1A1 codes for an inducible enzyme system that catalyzes the bioactivation of PAHs. Prior research found a high correlation in human lung tissue between CYP1A1 activity and DNA damage from PAHs. The CYP1A1 Mspi RFLP has been linked in some studies to risk of lung cancer. The relationships in human placenta between DNA damage, CYP1A1 activity and genotype have not been well characterized and may be relevant to risks from transplacental PAH exposure. The study cohort consisted of 70 newborns from Krakow, Poland, a city with elevated air pollution, and 90 newborns from nearby Limanowa, an area with lower air pollution but greater indoor coal use. Contrary to results seen previously in lung tissue, CYP1A1 mRNA was not significantly correlated with PAH-DNA adduct levels in the placenta. Smoking (self-reported maternal and infant plasma cotinine) was significantly associated with CYP1A1 mRNA levels (P < 0.01), but not with PAH-DNA adduct levels. Placental PAH-DNA adduct levels were significantly higher in infants with the CYP1A1 MspI restriction site compared with infants without the restriction site (P < 0.01), implicating a genetic factor in inter-individual variation in DNA damage in human placenta. Further studies are needed to determine the relevance of this finding to risk of transplacental carcinogenesis.

Evidence that a locus for familial high myopia maps to chromosome 18p

Myopia, or nearsightedness, is the most common human eye disorder. A genomewide screen was conducted to map the gene(s) associated with high, early-onset, autosomal dominant myopia. Eight families that each included two or more individuals with >=-6.00 diopters (D) myopia, in two or more successive generations, were identified. Myopic individuals had no clinical evidence of connective-tissue abnormalities, and the average age at diagnosis of myopia was 6.8 years. The average spherical component refractive error for the affected individuals was -9.48 D. The families contained 82 individuals; of these, DNA was available for 71 (37 affected). Markers flanking or intragenic to the genes for Stickler syndrome types 1 and 2 (chromosomes 12q13.1-q13.3 and 6p21.3, respectively), Marfan syndrome (chromosome 15q21.1), and juvenile glaucoma (chromosome 1q21-q31) were also analyzed. No evidence of linkage was found for markers for the Stickler syndrome types 1 and 2, the Marfan syndrome, or the juvenile glaucoma loci. After a genomewide search, evidence of significant linkage was found on chromosome 18p. The maximum LOD score was 9.59, with marker D18S481, at a recombination fraction of .0010. Haplotype analysis further refined this myopia locus to a 7.6-cM interval between markers D18S59 and D18S1138 on 18p11.31.

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.

Retinoblastoma and Hirschsprung disease in a patient with interstitial deletion of chromosome 13

Retinoblastoma is a rare pediatric malignancy (1/20,000) while Hirschsprung disease is a relatively common pediatric disorder (1/5,000). We describe a boy with bilateral retinoblastoma, Hirschsprung disease, multiple minor anomalies, and an interstitial deletion 13q (q13 --> q22). This child and a similar previously reported girl with retinoblastoma and Hirschsprung disease may represent a previously unrecognized contiguous gene syndrome.

Rigid gas permeable contact lens changes in the aphakic infant

PURPOSE

The purpose of this study was to describe and evaluate the frequent parameter changes required in aphakic infants fit with rigid gas permeable (RGP) contact lenses.

METHODS

Twenty-five eyes from 18 patients with congenital cataracts were fit postoperatively with RGP lenses and followed for an average of 19 months. The original lens specifications were determined by keratometer readings, corneal diameter, and axial length or retinoscopy obtained under sedation just prior to or after cataract extraction surgery. The frequency of changes in contact lens power, base curve, and diameter was recorded and analyzed.

RESULTS

Due to rapid growth and/or difficulty in achieving accurate measurements, repeated contact lens adjustments were needed to ensure proper power and fit.

CONCLUSIONS

The data contained in this study indicates a relatively stable period--from 6 to 12 months postoperatively--where the likelihood that contact lenses will need to be modified falls below 50%.

Extracorporeal membrane oxygenation causing asymmetric vasculopathy in neonatal infants

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is a form of cardiopulmonary bypass therapy used in term or near-term infants with severe cardiorespiratory disorders not responsive to conventional intensive care interventions. An ECMO-associated retinal vasculopathy has been described with little reference to the specific condition of the patient. We examined the eyes of 91 infants who underwent ECMO treatment. An assessment was made of the following: (1) when retinal changes occurred, (2) whether there was a particular systemic disorder or ECMO approach associated with these retinal findings, and (3) whether there may be ocular sequelae from this development.

METHODS

Ninety-one neonates were treated with ECMO for meconium aspiration syndrome (MAS), primary persistent pulmonary hypertension of the newborn, sepsis, congenital diaphragmatic hernia (CDH), respiratory distress syndrome (RDS), and blood aspiration. Venoarterial bypass was performed in 73 patients. The remaining 18 patients underwent venovenous bypass. Ophthalmologic examinations were performed during bypass in 6 infants and within 3 weeks of ECMO in the remainder.

RESULTS

Asymmetric retinopathy (left eye > right eye) was discovered in six infants with CDH and in one infant with RDS within a 2-week period after bypass, demonstrating venous tortuosity with or without intraretinal hemorrhages. One infant treated for MAS had a left eye intraretinal hemorrhage only. All patients with the noted retinal changes underwent venoarterial cannulation. Six of 9 patients with CDH had retinal findings noted compared with 1 of 10 patients with RDS and 1 of 35 patients with MAS.

CONCLUSION

Because we were able to examine infants while they were receiving ECMO or shortly after termination of bypass, asymmetric vasculopathy was found in a greater percentage of our patients compared with a similar large case series. ECMO-associated retinal vasculopathy appeared to disproportionately occur in those patients with CDH who underwent venoarterial bypass. Further study of retinal vascular changes in patients with CDH should be performed to assess long-term effects.

Variability in PAH-DNA adduct measurements in peripheral mononuclear cells: implications for quantitative cancer risk assessment

Biomarkers such as DNA adducts have significant potential to improve quantitative risk assessment by characterizing individual differences in metabolism of genotoxins and DNA repair and accounting for some of the factors that could affect interindividual variation in cancer risk. Inherent uncertainty in laboratory measurements and within-person variability of DNA adduct levels over time are putatively unrelated to cancer risk and should be subtracted from observed variation to better estimate interindividual variability of response to carcinogen exposure. A total of 41 volunteers, both smokers and nonsmokers, were asked to provide a peripheral blood sample every 3 weeks for several months in order to specifically assess intraindividual variability of polycyclic aromatic hydrocarbon (PAH)-DNA adduct levels. The intraindividual variance in PAH-DNA adduct levels, together with measurement uncertainty (laboratory variability and unaccounted for differences in exposure), constituted roughly 30% of the overall variance. An estimated 70% of the total variance was contributed by interindividual variability and is probably representative of the true biologic variability of response to carcinogenic exposure in lymphocytes. The estimated interindividual variability in DNA damage after subtracting intraindividual variability and measurement uncertainty was 24-fold. Inter-individual variance was higher (52-fold) in persons who constitutively lack the Glutathione S-Transferase M1 (GSTM1) gene which is important in the detoxification pathway of PAH. Risk assessment models that do not consider the variability of susceptibility to DNA damage following carcinogen exposure may underestimate risks to the general population, especially for those people who are most vulnerable.

Histopathology and vascular endothelial growth factor in untreated and diode laser-treated retinopathy of prematurity

OBJECTIVES

We had the unique opportunity to compare the eyes of a premature infant with stage 3 retinopathy of prematurity (ROP) in both eyes after the condition was treated by diode laser photocoagulation in one eye only. After the infant's death, we investigated the extent of structural damage incurred with the diode laser and examined the effect of treatment on vascular endothelial growth factor (VEGF) expression.

METHODS

The eyes were fixed and embedded in paraffin. Adjacent 6 microns sections were either stained for histopathologic analysis or used for in situ hybridization. VEGF messenger RNA (mRNA) was detected by using radiolabeled antisense riboprobes.

RESULTS

In the treated eye, histopathologic results demonstrated the clinically evident dose-response effect, with sparing of inner retinal elements with mild laser burns and full-thickness retinal cell disruption with severe burns. Scleral and ciliary nerve effects were absent. VEGF mRNA was localized primarily in the ganglion cell layer but was also found in the inner nuclear layer. In the untreated eye, an increase in VEGF mRNA was detected at the peripheral edge of the vascularized retina anterior to the ridge. In the laser-treated eye, VEGF mRNA expression was dramatically upregulated in the ganglion cell layer in areas adjacent to laser burns.

CONCLUSIONS

VEGF mRNA was found to be elevated in the peripheral, avascular retina of the untreated eye, consistent with the hypothesis that retinal hypoxia stimulates VEGF expression. In the treated eye with recurrent ROP, VEGF mRNA was not detected in the photocoagulated areas of retina but was increased between laser scars. This finding confirms the results of prior animal studies and validates the use of these models.

Myopia predicts better outcome in persistent hyperplastic primary vitreous

PURPOSE

Persistent hyperplastic primary vitreous (PHPV) is a congenital disorder that presents with a spectrum of ocular anomalies, including cataracts, microphthalmia, and hyaloid vessel remnants. Severe visual loss due to secondary glaucoma and retinal detachment is common. This report evaluates the visual outcome of a variant of PHPV with myopia not associated with glaucoma.

METHODS

The records of 23 consecutive patients with the diagnosis of PHPV (all unilateral) from October 1992 to August 1995 were reviewed. All but three patients had a cataract extraction procedure and all underwent amblyopia therapy. Eyes with a phakic myopic refractive error (Rx) or aphakic refractive correction < or = 8.5 diopters (D) in the immediate postoperative period were designated as myopic.

RESULTS

Six patients were in the myopic group (Group 1) and 17 in were the nonmyopic group (Group 2). The mean age of diagnosis was 21.1 months in Group 1 versus 2.0 months in Group 2, with a comparable follow-up period of 36 months. The mean preoperative Rx of Group 1 was -7.78 D. The mean aphakic Rx of Group 2 was +18.29 D. Average axial length measurement determined by echography was 22.46 mm in Group 1 and 14.03 mm in Group 2. The mean corneal diameter was 11.3 mm in Group 1 vs 8.9 mm in Group 2. In Group 2, seven eyes developed retinal detachment and four developed glaucoma. These complications did not develop in Group 1 during the follow-up period. Overall functional visual acuity was better in Group 1, with a median visual acuity at final follow up of 20/160, as compared with light perception for Group 2.

CONCLUSIONS

PHPV eyes with myopia were not detected as early as the typical PHPV eyes, primarily because of less media opacification and near-normal corneal diameters. These eyes showed a more favorable visual outcome as they were less likely to develop typical PHPV-related postoperative complications. Myopic PHPV eyes may require a different management approach.

Polycyclic aromatic hydrocarbon-DNA adducts in beluga whales from the Arctic

The Arctic is still relatively pristine in nature, but it is also vulnerable to pollution because contaminants originating from midlatitudes are transported to the Arctic by atmospheric processes, ocean currents, and rivers (Muir et al., 1992). Recognition of this fact of Arctic vulnerability has resulted in a Declaration on the Protection of the Arctic Environment by eight Arctic countries. A manifest aim of this declaration is to develop an Arctic Monitoring and Assessment Program. We report here on the presence of measurable levels of polycyclic aromatic hydrocarbon-DNA adducts, including relatively high levels in Arctic beluga (Delphinapterus leucas). These results lend support to the value of developing biological assessment programs for Arctic wildlife.

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.

The association of strabismus, amblyopia, and refractive errors in spasmus nutans

PURPOSE

Spasmus nutans is a condition that includes asymmetric nystagmus and occurs during the amblyogenic period. Because specific alterations in early visual experience are known to be associated with changes in visual development, relations between spasmus nutans and abnormal visual sequelae were examined.

METHODS

The records of 18 patients with spasmus nutans were reviewed retrospectively. The incidence of strabismus, amblyopia, anisometropia, and astigmatism was compared with published age-matched control subjects.

RESULTS

There was a significantly higher incidence of strabismus (10 of 18) and amblyopia (8 of 18) of the eye with the greater amplitude of nystagmus. No correlation of refractive error with lateralization of nystagmus could be established. Twelve of 18 patients required spectacles for improvement in visual acuity and for treatment of amblyopia. Best-corrected visual acuity averaged 1.20 Snellen lines poorer than age-adjusted normative values; however, loss of visual acuity was, in most cases, symmetric and not related to lateralization of nystagmus.

CONCLUSION

Early detection and treatment of anticipated abnormal visual issues in patients with spasmus nutans will optimize visual outcomes.

A sensitive color ELISA for detecting polycyclic aromatic hydrocarbon-DNA adducts in human tissues

Human exposure to polycyclic aromatic hydrocarbons (PAHs) has been determined by measurement of DNA adducts in human tissues. Competitive enzyme-linked immunosorbent assays (ELISAs) using antisera recognizing benzo[a]pyrenediol-epoxide-modified DNA (BPDE-I-DNA) and color of fluorescence endpoint detection have been used extensively for quantifying PAH-DNA adducts. The fluorescence ELISA (limit of detection 1 adduct/10(8) nucleotides) was previously reported to be more sensitive than the color ELISA (1/10(7)) for measuring PAH adducts (Santella et al. (1988) Carcinogenesis, 9, 1265-1269). However, the fluorescence assay has the disadvantages of greater variation among the replicates and higher background levels than the color assay. Using a newly developed antiserum against BPDE-I-DNA, we have modified the color of ELISA so that it has the same sensitivity as the fluorescence ELISA and requires only 33% of the sample quantity needed for the fluorescence ELISA. The modifications included preincubation of the antiserum with the samples, using microtiter plates with half-size, flat bottom wells, and optimizing the assay conditions. The improved color ELISA was used to analyze DNA samples from human autopsy tissues, including heart, lung, liver, kidney, spleen, pancreas and stomach from smokers and nonsmokers. With the exception of spleen and stomach, all tissues from smokers showed higher PAH-DNA adducts (ranging from 0.3 to 19.0 adducts/10(7) nucleotides) than the tissues from the nonsmokers (0.3 to 3.7 adducts/10(7) nucleotides) in two separate experiments. Among the tissues from smokers, heart showed the highest level of DNA adducts. This study demonstrates that a stable color ELISA with high sensitivity can be useful in assessing human exposure to PAH.

Clinical effectiveness and quality of life with ranitidine vs placebo in gastroesophageal reflux disease patients: a clinical experience network (CEN) study

BACKGROUND

Gastroesophageal reflux disease (GERD), often characterized as heartburn, is a highly common presenting complaint to family physicians. This study is the first large, prospective, nationwide family practice outpatient evaluation of the effectiveness of the histamine (H2)-receptor antagonist ranitidine as medical therapy for this disorder.

METHODS

This randomized, double-blind, placebo-controlled, parallel group, 6-week study was designed to evaluate the effect of ranitidine on clinical outcomes and quality of life in patients with GERD. Eligible patients included those who were at least 18 years old and had at least a 3-month history of heartburn or heartburn therapy and a minimum of 4 days with at least one heart-burn episode in the week preceding the baseline visit. Quality-of-life effects were measured using a general health status instrument and a previously validated heartburn-specific questionnaire.

RESULTS

Ranitidine treatment conferred clinically and statistically significant reductions in mean heartburn pain scores within the first 24 hours (P < or = .001) and mean number of heartburn episodes within the first 48 hours (P < or = .001). These reductions were maintained throughout the 6-week trial, during both daytime and nighttime. Compared with patients receiving placebo, patients treated with ranitidine also used significantly fewer doses of antacids (P < or = .003). Further, both ranitidine-treated patients' and their physicians' global assessments of decreases in heartburn severity, as well as clinical improvement on ranitidine, proved superior to those of controls (P < or = .001). The rate of adverse events associated with ranitidine and placebo was low and similar. Ranitidine-treated patients had more favorable scores on the general health status dimensions of physical functioning, bodily pain, and vitality (P < .05), and more favorable scores on all dimensions of the heartburn-specific questionnaire (P < .05).

CONCLUSIONS

Twice-daily treatment with ranitidine 150 mg is a valuable therapy for GERD in a typical family practice setting. It reduces the frequency and severity of symptoms within the first 24 to 48 hours of treatment and diminishes the use of nonprescription antacids while improving the quality of life as measured by both a general health status instrument and a disease-specific instrument.

A molecular epidemiological case-control study of lung cancer

Polycyclic aromatic hydrocarbon-DNA adducts were measured by ELISA in peripheral leukocytes from 119 non-small cell lung cancer patients and 98 controls at the Columbia-Presbyterian Medical Center. Thirty-one cases had adduct measurements in leukocytes, lung tumor, and nontumor specimens collected at surgery, and 34 had paired leukocyte and tumor specimens. Information on smoking, diet, and occupational exposure was collected. After adjustment for age, gender, ethnicity, season, and smoking, adducts in leukocytes were significantly higher in cases (P < 0.01) than controls; the odds ratio was 7.7 (95% confidence interval = 1.7-34; P < 0.01). Adducts in leukocytes were increased significantly in smokers and ex-smokers compared to nonsmokers among cases and controls (separately and combined) after adjusting for age, gender, ethnicity, and season (P < 0.05). The cases and controls differed in several respects: (a) adducts increased with the number of cigarettes smoked among the 51 cases who were current smokers (P = 0.05) but not among the current smokers in the controls; and (b) a seasonal variation in DNA binding, corresponding to that reported for aryl hydrocarbon hydroxylase inducibility, was observed in cases but not in controls. Among the cases, adducts in leukocytes were correlated more strongly with adducts in the lung tumor tissue than with those in nontumor lung tissue. The results in leukocytes are consistent with a constitutional susceptibility to lung cancer, which results in greater DNA damage from carcinogens in cigarette smoke. They suggested that it may ultimately be possible to use biomarkers such as adducts to identify individuals who would benefit most from early intervention.

Polycyclic aromatic hydrocarbon-DNA and protein adducts in coal tar treated patients and controls and their relationship to glutathione S-transferase genotype

Coal tar treated psoriasis patients were used as a model population to evaluate a panel of immunoassays for monitoring exposure to benzo[a]pyrene (BP) and related polycyclic aromatic hydrocarbons (PAH). The assays included measurement of PAH diol epoxide-DNA adducts in white blood cells by competitive enzyme-linked immunosorbent assay (ELISA) with fluorescence endpoint detection, PAH-albumin adducts by competitive ELISA with color endpoint detection and serum levels of antibodies recognizing BP diol epoxide-DNA adducts by noncompetitive color ELISA. PAH-DNA adducts by ELISA were elevated in patients (mean 6.77 +/- 12.05/10(8)) compared to controls (4.90 +/- 8.81/10(8), p = 0.12). There was no difference in PAH-albumin adducts between patients (mean 0.61 +/- 0.31 fmol/micrograms) and controls (0.63 +/- 0.30 fmol/micrograms). Glutathione S-transferase M1 genotype was also determined but no relationship was found between presence of the gene and either DNA or protein adduct levels. About 30% of both patients and controls had measurable titer of antibodies recognizing BPDE-I-DNA adducts. Measurement of white blood cell DNA adducts by ELISA was the most sensitive method for detecting PAH exposure in coal tar-treated psoriasis patients.

Association of intraocular pressure and myopia in children

PURPOSE

While elevated intraocular pressure (IOP) is associated with myopia in adults, its potential influence on the growth of eyes in juveniles without glaucoma is controversial. To address this issue, a possible relation between IOP and refraction in children was sought.

METHODS

A cross-sectional survey of IOP was conducted in children presenting to the Division of Pediatric Ophthalmology at The Children's Hospital of Philadelphia for a complete eye examination. Measurement of IOP was attempted in all children, including those with amblyopia, prematurity, and strabismus. Exclusion criteria were abnormalities of the posterior pole and/or conditions such as cataract that precluded assessment of refractive error. For analysis, myopia was defined as a spherical equivalent of more than 1 diopter (D) of myopia. Logistic regression was used to assess the association between other patient characteristics and presence of myopia.

RESULTS

Intraocular pressure testing was attempted in all age groups, but was more successful in older children. Reliable readings were obtained on 321 subjects. The mean age was 9.8 years, with a mean IOP of 17.3 mmHg in the right eye and 17.2 mmHg in the left and a mean spherical equivalent of +0.2 D in the right eye and +0.1 D in the left. Increasing age, a family history of myopia, and amblyopia were associated myopia. Increasing IOP also was related to myopia. Even when patients with amblyopia, strabismus, and prematurity were exclude, age, family history of myopia, and IOP again were associated with myopia.

CONCLUSIONS

These results indicate that IOP in children may be higher in myopic than nonmyopic eyes. Whether IOP could contribute to the mechanisms causing the abnormal eye growth of childhood myopia requires further study.

Polycyclic aromatic hydrocarbon-DNA adducts in smokers and their relationship to micronutrient levels and the glutathione-S-transferase M1 genotype

Sixty-three male cigarette smokers were entered into a cross-sectional study to determine whether inverse associations existed between polycyclic aromatic hydrocarbon (PAH)-DNA adduct levels and intake/serum levels of vitamin A, vitamin C and vitamin E. Associations between PAH-DNA adducts and intakes of carotene, as well as serum levels of beta-carotene, were also determined. Fasting blood samples were collected for assays of PAH-DNA adducts in circulating mononuclear cells, plasma cotinine and serum levels of vitamin A, beta-carotene, vitamin C and vitamin E. Since genetic deficiency in the detoxifying enzyme glutathione S-transferase M1 (GSTM1) has been associated with increased risk of lung cancer, GSTM1 genotype was also determined. Analysis of PAH-DNA adducts by competitive enzyme-linked immunosorbent assay (ELISA) indicated that 70% of the subjects had detectable adducts, with a mean of 4.38 adducts/10(8) nucleotides (range 1.00-24.1/10(8)). Pearson's method was utilized to determine whether any associations existed between the various host variables and PAH-DNA adducts. Previously, no significant associations were found between PAH-DNA adducts and cigarettes smoked/day, pack-years, daily/life-time tar exposures or plasma cotinine levels (Santella et al., Carcinogenesis, 13, 2041-2045, 1992). PAH-DNA adducts were inversely associated with serum cholesterol-adjusted vitamin E levels (r = -0.25, P < or = 0.05) and with smoking-adjusted vitamin C serum levels (r = -0.22, P < or = 0.09). Stratification by GSTM1 genotype indicated that these associations were limited to subjects with the null genotype. The relationship between adducts and serum cholesterol-adjusted vitamin E was significant in those of the null genotype (r = -0.38, P < or = 0.04), but not in those with the gene present (r = -0.12, P = 0.5). Similarly, for smoking-adjusted vitamin C, the relationship with adducts was stronger in subjects with the null genotype (r = -0.35, P < or = 0.06) than in those with GSTM1 present (r = -0.05, P = 0.77). These results are consistent with findings of prior epidemiological studies identifying significant inverse associations between anti-oxidant micronutrient status or GSTM1 genotype and the incidence of lung cancer. Additional studies should be conducted to confirm a possible role for vitamin E in PAH-DNA adduct formation and to explore further the possible roles of vitamin A, beta-carotene and vitamin C in modulating adduct formation and lung cancer risk.

Hereditary nonpolyposis colon cancer: analysis of linkage to 2p15-16 places the COCA1 locus telomeric to D2S123 and reveals genetic heterogeneity in seven Canadian families

Hereditary nonpolyposis colon cancer (HNPCC) is an autosomal dominant trait responsible for approximately 6% of colorectal cancers. Linkage of the HNPCC trait to the D2S123 locus on 2p15-16 has previously been reported in two families. This HNPCC locus is now designated "COCA1." We have tested seven Canadian HNPCC families, who have a variety of clinical presentations, for linkage to a panel of microsatellite polymorphisms in the vicinity of D2S123. One family was clearly linked to the COCA1 locus (LOD = 4.21), and a second family is likely to be linked (LOD = 0.92). In three families linkage was excluded. In the remaining two families the data were inconclusive. In the linked family, individuals with cancer of the endometrium or ureter share a common haplotype with 12 family members with colorectal cancer. This supports the suspected association between these extracolonic neoplasms and the HNPCC syndrome. In addition, five of the six individuals with adenomatous polyps (but no colorectal cancer) have the same haplotype as the affected individuals, while the sixth carries a recombination. One individual with colorectal cancer carries a recombination that places the COCA1 locus telomeric to D2S123. This study localizes the COCA1 gene to an 8-cM region that is consistent with the location of the hMSH2 gene. We also confirm that families presently classified as HNPCC are genetically heterogeneous.

Economic impact of cost-containment strategies in third party programmes in the US. Part II

This is the second article in a 2-part series that examines the economic impact of several different strategies used to control costs in third party programmes. This article investigates 5 different methods: (a) formularies; (b) capitation; (c) drug utilisation review; (d) prior approval; and (e) drug product selection. The published literature indicates that use of formularies decreases drug expenditures, but these savings may be offset by expenditures in other areas of healthcare programmes. Capitation, though less well studied than other strategies, may show some effectiveness in reducing costs by increasing generic dispensing and promoting switching from prescription drug to over-the-counter. Drug utilisation review, as a systematic programme of claims data review, has been shown to yield positive economic return in a variety of areas, including both impersonal and face-to-face educational interventions with healthcare practitioners. Prior approval and drug product selection both result in savings when examined in isolation from other aspects of healthcare. Cost-shifting, administrative costs and costs incurred because of possible decreased access to care have yet to be fully accounted for.

DNA adducts as biomarkers for assessing exposure to polycyclic aromatic hydrocarbons in tissues from Xuan Wei women with high exposure to coal combustion emissions and high lung cancer mortality

The high lung cancer rate in Xuan Wei, China, is associated with smoky coal use in unvented homes, but not with wood or smokeless coal use. Smoky coal combustion emits higher polycyclic aromatic hydrocarbon (PAH) concentrations than wood combustion. This study used DNA adducts as biomarkers for human exposure to PAH from combustion emissions. DNA adducts were determined by enzyme-linked immunosorbent assays (ELISA) in placentas and peripheral and cord white blood cells (WBC) from Xuan Wei women burning smoky coal or wood and from Beijing women using natural gas. Color ELISA gave positive results in 58, 47, and 5% of the placentas from Xuan Wei women burning smoky coal without and with chimneys, and from Beijing women, respectively. Fluorescence ELISA indicated that 46, 65, 56, and 25% of placentas were positive from Xuan Wei women who lived in houses without and with chimneys, Xuan Wei women burning wood, and Beijing controls, respectively. Peripheral WBC samples were positive in 7/9, 8/9, and 3/9 for the Xuan Wei women who lived in houses without and with chimneys and Beijing women, respectively. PAH-DNA adducts were detected in a higher percentage of placentas from Xuan Wei women living in houses exposed to smoky coal or wood emissions than from those of the Beijing controls. No dose-response relationship was observed between the air benzo[alpha]pyrene concentrations and DNA adduct levels or percentage of detectable samples. The results suggest that DNA adducts can be used as a qualitative biomarker to assess human exposure to combustion emissions.

Polycyclic aromatic hydrocarbon-DNA adducts in white blood cells and urinary 1-hydroxypyrene in foundry workers

In an ongoing comprehensive evaluation of biological markers, workers in or near an iron foundry with varying exposure to polycyclic aromatic hydrocarbons (PAH) were analyzed for molecular response to this exposure. Exposure to benzo(a)pyrene, determined by personal monitors worn by the workers (2 to 60 ng/m3), was considerably lower than in a previous study at this foundry (< 50 to 200 ng/m3) (F.P. Perera et al., Cancer Res., 48: 2288-2291, 1988). Two biomarkers, 1-hydroxypyrene in urine measured by high-performance liquid chromatography with fluorescence detection (a measure of internal dose) and PAH-DNA adducts in WBC measured by immunoassay (a measure of biologically effective dose) were assessed to demonstrate their relationship to the lowest exposures yet analyzed in foundry workers. In addition, these markers were analyzed for dose response and interindividual variability. Cigarette smoking, but not age or charbroiled food, influenced the level of 1-hydroxypyrene but not PAH-DNA adducts. When workers were classified into three exposure categories (low, medium, and high), mean 1-hydroxypyrene levels were 2.7, 1.8, and 3.6 mumol/mol creatinine, respectively. Comparisons by analysis of variance showed a significant difference between the groups after controlling for smoking (P = 0.02), but a trend test using multivariate linear regression analysis was not significant (r = 0.27; P = 0.07). Substantial interindividual variation was demonstrated by the 19- to 20-fold range in the values within each of the three exposure groups.(ABSTRACT TRUNCATED AT 250 WORDS)

The ophthalmologic manifestations of the cardio-facio-cutaneous syndrome

The cardio-facio-cutaneous (CFC) syndrome is an uncommon multiple congenital anomalies/mental retardation syndrome whose major manifestations are congenital heart defects, relative macrocephaly, stunted growth, ectodermal dysplasia, characteristic facial appearance, and psychomotor developmental delay. All described cases were sporadic and cytogenetically normal. We report three additional patients with this diagnosis. All three patients developed strabismus, requiring extraocular muscle surgery. Two of our patients also had nystagmus. Combining the 18 previously reported cases with our additional 3, 9 of 21 had strabismus, 10 of 21 had ptosis, and 6 of 21 had nystagmus. Ophthalmic craniofacial abnormalities of hypoplastic supraorbital ridges, prominent epicanthal folds, and antimongoloid slant of the palpebral fissures were also common features contributing to the characteristic facies described for this syndrome. The ophthalmologist could aid in the diagnosis and treatment of these patients because of the prominent ophthalmologic symptomatology of the CFC syndrome.

Molecular and genetic damage in humans from environmental pollution in Poland

Extreme environmental pollution such as that found in the highly industrialized Silesian region of Poland has been associated with increased risk of cancer and adverse reproductive outcomes. Among the most prevalent carcinogenic and mutagenic air pollutants in Silesia are the polycyclic aromatic hydrocarbons (PAH) which are largely produced by industrial and residential combustion of coal. Molecular epidemiology aims to prevent disease by using biological markers to identify risks well before clinical onset to allow effective intervention. Here, we use a battery of biological markers to measure molecular and genetic damage in peripheral blood samples from residents of Silesia and from persons living in a rural, less polluted area of Poland. The results show that their exposure to environmental pollution is associated with significant increases in carcinogen-DNA adducts (PAH-DNA and aromatic adducts), in sister chromatid exchange including high-frequency cells, and in chromosomal aberrations as well as a doubling in the frequency of ras oncogene overexpression. We found that aromatic adducts on DNA were significantly correlated with chromosomal mutation, providing us with a molecular link between environmental exposure and a genetic alteration relevant to cancer and reproductive risk.

Cigarette smoking related polycyclic aromatic hydrocarbon-DNA adducts in peripheral mononuclear cells

Studies on cigarette smoking related polycyclic aromatic hydrocarbon-DNA adducts in blood have produced conflicting results. To determine whether a subset of specific white blood cells is a useful marker for monitoring exposure to cigarette smoke, blood was obtained from 63 heavy smokers and 27 non-smokers. Adduct levels were determined by competitive enzyme-linked immunosorbent assay with a polyclonal antiserum recognizing benzo[a]pyrene and structurally related diolepoxide-DNA adducts. Analysis of the lymphocyte plus monocyte fraction from smokers indicated 70% had detectable adducts with a mean of 4.38 +/- 4.29 adducts/10(8) nucleotides, while in non-smokers the corresponding values were 22% and 1.35 +/- 0.78/10(8) (P < 0.001). Plasma cotinine levels differed significantly in smokers (286 +/- 90 micrograms/l) compared to non-smokers (4.4 +/- 3.3 micrograms/l) (P < 0.001). However, cotinine was not correlated with self-reported smoking history in these heavy smokers. Nor were DNA adducts in smokers correlated with cigarettes per day, pack-years and plasma cotinine, indicating large interindividual variation in DNA adduct formation. These data demonstrate lymphocytes plus monocytes from smokers have elevated levels of polycyclic aromatic hydrocarbon diolepoxide-DNA adduct levels compared to non-smokers.

Congenital unilateral fibrosis, blepharoptosis, and enophthalmos syndrome

The authors report four cases of the rarest form of the congenital fibrosis syndrome. This disorder is exhibited in infancy as unilateral blepharoptosis, strabismus, limited ductions, globe displacement (enophthalmos and blepharoptosis), and decreased vision, usually due to amblyopia. Forced ductions are positive and surgical exploration confirms anomalous muscle structure. Computed tomography and magnetic resonance imaging studies in these four patients were diagnostically beneficial, showing extraocular muscle and tendinous insertion involvement, and poorly defined intraconal and extraconal masses that had the appearance of scar or inflammatory tissue. All patients had globe displacement. The opposite eye and intracranial contents were normal in all of our patients. Results of histopathologic examination obtained at surgery in three of these patients show replacement of affected structures by fibrous tissue and included the extraocular muscles, orbital fat, Tenon's capsule, and conjunctiva.

Infantile glaucoma associated with the Diamond-Blackfan syndrome

Diamond-Blackfan syndrome is a rare congenital hematologic disorder characterized by isolated erythroid hypoplasia. Physical abnormalities such as short stature, thumb deformities, and ophthalmic findings including strabismus, hypertelorism, and microphthalmos have been reported to occur with this disease entity. We describe two patients with this blood dyscrasia and infantile glaucoma with trabeculodysgenesis. Both patients underwent multiple surgical procedures to control their glaucoma. The patients were on chronic systemic adrenal corticosteroid therapy for their anemia, which caused some confusion regarding the etiology of their glaucoma. To our knowledge, this is the first report of an association of infantile glaucoma with Diamond-Blackfan syndrome. We hope this report will encourage early recognition and treatment of glaucoma in patients with this disorder.

Biologic markers in risk assessment for environmental carcinogens

The potential of biologic markers to provide more timely and precise risk assessments for environmental carcinogens is viewed against the current state-of-the-art in biological monitoring/molecular epidemiology. Biologic markers such as carcinogen-DNA adducts and oncogene activation are currently considered valid qualitative indicators of potential risk, but for most chemical exposures research is needed to establish their validity as quantitative predictors of cancer risk. Biologic markers have, however, already provided valuable insights into the magnitude of interindividual variation in response to carcinogenic exposures, with major implications for risk assessment.

Respiratory epithelium in a cystic choristoma of the limbus

A female newborn had a cystic, whitish gray mass at the inferotemporal limbus of the left eye. At age 3 weeks, the newborn underwent excision of the tumor, corneal patch grafting, and superior sector optical iridectomy. Histopathologic and electron microscopic examination of the excised tissue revealed a choristoma consisting of cysts lined with respiratory epithelium. To our knowledge, respiratory epithelium in a limbal choristoma has not been previously reported.

Effects of topical glaucoma drugs on fistulized rabbit conjunctiva

Conjunctival fibroblastic proliferation with contracting scar formation has been implicated as a possible cause of glaucoma filtering surgery failure. The effects of glaucoma medications on bulbar conjunctiva were evaluated in both eyes of 20 pigmented rabbits, with 5 rabbits per group each receiving singular topically applied daily doses of either 0.5% timolol, 1% epinephrine, 4% pilocarpine, or artificial tears in a masked fashion for 4 months. Posterior lip sclerectomies were performed in 16 rabbits--4 from each treatment group. The remaining four rabbits served as nonsurgical controls. Four additional rabbits, which had not received eye drops, were included as a nonmedicated control group, with one rabbit serving as a nonsurgical control. Immunostaining was performed to identify the presence of myofibroblasts in fistulized conjunctiva. Treated surgical eyes, regardless of medication, had higher myofibroblastic cell proliferation than treated nonsurgical eyes. Among fistulized eyes, all medications increased cell proliferation, with pilocarpine eliciting the most dramatic increase compared with all other groups.

Development of monoclonal antibodies recognizing 7-(2-hydroxyethyl)guanine and imidazole ring-opened 7-(2-hydroxyethyl)guanine

7-(2-Hydroxyethyl)guanine (7HEG) is of biological interest because it is formed in vivo by reaction of DNA with ethylene oxide (EO). Furthermore, the major DNA adduct of vinyl chloride, 7-(2-oxyethyl)guanine, can be converted to this adduct by reduction. Two monoclonal antibodies (9E2, 4A5) recognizing 7HEG have been developed from BALB/c mice immunized with the adduct coupled to keyhole limpet hemocyanin. In addition, another antibody (8E10) was developed against the imidazole ring-opened form of the adduct (ro-7HEG). ELISAs were used to determine the sensitivity and specificity of these antibodies. With antibody 9E2, 50% inhibition of antibody binding in the competitive ELISA was at 54 pmol of the modified base 7HEG/well and 67 pmol 7HEGR/well, while with antibody 4A5, the values were 3.6 pmol 7HEG/well and 6.7 pmol 7HEGR/well. Antibody 8E10 gave 50% inhibition at 48 pmol ro-7HEGR/well. Neither antibody 9E2 nor 8E10 cross-reacted with unmodified DNA or with the normal nucleosides at the highest concentration tested. However, antibody 4A5 had a low affinity for deoxyguanosine (50% inhibition at 31,000 pmol). Sensitivity of adduct measurement can be increased 3- to 10-fold using an ELISA with fluorescence endpoint detection. These antibodies have been used to determine the level of adducts in DNA modified in vitro with [3H]- or [14C]EO. Because of the cross-reactivity of the most sensitive antibody, 4A5, with deoxyguanosine, a combined HPLC/immunoassay method was developed to quantitate 7HEG in DNA. The limit of sensitivity of this method is dependent upon the amount of DNA available for analysis. Using 30 fmol as the lowest detectable amount (20% inhibition) in the fluorescent ELISA with antibody 4A5 and 100 micrograms of DNA assayed per well, adduct levels of 1/10(7) nucleotide can be determined. This method was applied to DNA adduct detection in EO-treated myeloma cells and whole blood. Antibody 8E10 was also used in immunohistochemical studies to visualize ring-opened adducts in cells treated with EO followed by high pH. These antibodies will be used for the detection and quantitation of adducts in human samples.

Postlabeling and immunoassay analysis of polycyclic aromatic hydrocarbons--adducts of deoxyribonucleic acid in white blood cells of foundry workers

Blood samples were obtained from volunteers who were occupationally exposed to polycyclic aromatic hydrocarbons in a Finnish iron foundry and from referents not known to be occupationally exposed to this class of chemical carcinogens. Aromatic adducts were determined in the deoxyribonucleic acid of white blood cells from the exposed workers with the 32P-postlabeling and immunologic techniques. There was a correlation between the estimated exposure in a particular job and the adduct levels. Jobs of men with high adduct levels (greater than 1 adduct/10(7) nucleotides in the postlabeling assay) included sand preparation, molding, shake-out, and transport. The adduct levels were low in men in pattern making, melting, and fettling. This study suggests that 32P-postlabeling and immunoassay may be useful in monitoring human exposure to known and previously unidentified environmental genotoxic agents.

Empirical and physiological assessment of in vitro growth in the mermithid nematode Romanomermis culicivorax

In vitro growth of Romanomermis culicivorax preparasites was monitored in two culture media under differing conditions of crowding. Crowding was more important than the character of the medium itself in stimulating in vitro growth. The glycogen, protein, and lipid content of nematodes that had developed after 5 weeks under crowded conditions was significantly greater than that of uncrowded nematodes. The lipid content of such crowded nematodes was greater than that of nematodes after 4 days of in vivo development, although glycogen and protein levels were lower than the 4 day in vivo norm. Nematodes that had developed in vitro contained a higher proportion of long-chain and polyunsaturated fatty acids than did nematodes cultured in vivo. The significance of these findings is discussed in relation to the establishment of a continuous in vitro culture system for this nematode.

Herpes simplex keratitis in patients with acquired immune deficiency syndrome

Acquired immune deficiency syndrome (AIDS) is associated with a wide spectrum of systemic and ocular infectious diseases. Little information is known about herpes simplex virus type 1 (HSV-1) keratoconjunctivitis in association with AIDS. The authors present six cases of recurrent HSV keratitis occurring in AIDS patients. Features of the herpetic keratitis in these patients included unilateral dendritic or geographic epithelial keratopathy; predilection for peripheral versus central corneal involvement; one to three recurrences per patient over a mean observation period of 17 months, with a median dendrite-free interval of 7 months; and a moderately prolonged clinical course with a median healing time of 3 weeks using topical antiviral therapy. Only one of six cases had stromal infiltrative involvement. These cases raise the question of whether the immunologic abnormalities associated with AIDS may affect the clinical characteristics and course of HSV keratitis.

Comparison of DNA adducts and sister chromatid exchange in lung cancer cases and controls

In a molecular epidemiological study of lung cancer cases (n = 81) and noncancer controls (n = 67), polycyclic aromatic hydrocarbon (PAH)-DNA adducts were evaluated in peripheral blood leukocytes from all subjects and in a smaller number of lung tissue specimens collected prior to or at surgery. Sister chromatid exchanges (SCE) in lymphocytes were also studied in a subset of cases and controls. Questionnaire, medical record, or tumor registry data provided a family history of cancer, as well as information on cigarette smoking, dietary and occupational exposure to PAHs, and other factors related to SCEs. In both cases and controls PAH-DNA adducts in leukocytes measured by an enzyme-linked immunosorbent assay were not significantly related to age, sex, ethnicity, amount of cigarette smoking, passive smoking, dietary charcoal, or caffeine consumption. Nor did family history of cancer or histological type of cancer significantly affect adduct levels. However, when subjects were stratified by smoking status (current, former, and nonsmoker), lung cancer cases who were current smokers had significantly higher levels of covalent adducts than current smoker controls. A seasonal variation was observed in PAH-DNA binding, with a peak in adduct levels during July-October. This peak corresponds to that seen in a prior study of aryl hydrocarbon hydroxylase inducibility by other investigators. The finding of significant levels of PAH-DNA adducts in former smokers and non-smokers supports an earlier observation that this marker is not smoking specific but reflects a pervasive and variable "background" exposure to PAH. These results are consistent with a genetically determined enhancement of PAH-DNA adduct formation in leukocytes of lung cancer cases which is evident in current smokers. The results in lung tissue are limited by the small number of samples. Adduct levels were not significantly increased in lung tissue of smokers compared with nonsmokers. An inverse linear correlation was seen between adduct values in lung tissue and age of the donors. SCEs were significantly related to pack years of smoking. However, there was no difference in the frequency of SCE between cases and controls; nor were SCE and DNA adducts significantly correlated in this small sample.

Interlaboratory comparison of antisera and immunoassays for benzo[a]pyrene-diol-epoxide-I-modified DNA

An interlaboratory comparison of immunoassays using antisera elicited against benzo[a]pyrene-diol-epoxide-modified DNA (BPDE-I-DNA) was carried out resulting in standardization of antisera, competitors and assay conditions. The assays used included competitive enzyme-linked immunosorbent assays (ELISA) with color and fluorescence endpoint detection and an ultrasensitive enzyme radioimmunoassay (USERIA) with a radioactive endpoint. Three different antisera were compared, two of which were obtained from different rabbits immunized with the same BPDE-I-DNA and a third from an animal immunized with another BPDE-I-DNA sample. Samples of standardized BPDE-I-DNA with high (36 pmol adduct/microgram DNA; 1.2 adducts/10(2) nucleotides) and low (4.5 fmol/microgram DNA; 1.5 adducts/10(6) nucleotides) modification levels were prepared and used in each laboratory. The antisera were all elicited against DNAs modified to a high extent, and it was therefore not surprising that they detected adducts in a slightly modified DNA sample with lower efficiency than those in highly modified DNA samples. The discrepancy of antibody recognition between the highly and slightly modified samples varied between 1.4- and 11.2-fold depending on the antiserum and assay. To ascertain the quantitative capability of the immunoassays, the modification level of DNA isolated from mouse keratinocytes treated with [3H]benzo[a]pyrene was determined by radioactivity and immunoassay. These results indicated that when a biological sample is assayed against a BPDE-I-DNA standard modified in the same range as the biological samples (4.5 fmol/microgram), quantitative recovery of adducts is achieved by immunoassay. These studies resulted in the realization that interlaboratory differences in immunoassay procedure can have significant consequences for data comparison and that where possible it is preferable for laboratories to use the same antisera and modified DNA standards.

Detection of polycyclic aromatic hydrocarbon-DNA adducts in white blood cells of foundry workers

Iron foundry workers, exposed to high levels of polycyclic aromatic hydrocarbons (PAHs), silica, and metal fumes and dusts, are at elevated risk of lung cancer. Benzo(a)pyrene and a number of structurally related PAHs are metabolically activated to diol epoxides (e.g., 7 beta,8 alpha-dihydroxy-9 alpha,10 alpha-epoxy-7,8,9,10-tetrahydrobenzo(a) pyrene) which are mutagenic, carcinogenic in experimental animals, and form covalent adducts with DNA. The levels of these adducts were measured in an enzyme-linked immunosorbent assay using a polyclonal anti-benzo(a)pyrene diol epoxide-I-DNA antibody which cross-reacts with DNA modified by diol epoxides of structurally related PAHs. DNA was analyzed from peripheral blood cells of 35 Finnish foundry workers and 10 controls. Workers were classified as having low (less than 0.05 micrograms/m3), medium (0.05-0.2 micrograms/m3), or high (greater than 0.2 micrograms/m3) exposure to benzo(a)pyrene (as an indicator of PAH). When adjustment was made for cigarette smoking and time since vacation, benzo(a)pyrene exposure was significantly related to adduct levels (P = 0.0001). Each of the three exposure groups had significantly elevated adduct levels compared to controls. Among the exposed workers, the low group differed significantly from the high and medium categories. This study supports the usefulness of monitoring adduct formation in a population occupationally exposed to carcinogens.

Development of techniques to monitor for exposure to vinyl chloride: monoclonal antibodies to ethenoadenosine and ethenocytidine

Monoclonal antibodies which specifically recognize ethenoadenosine and ethenocytidine, two of the adducts resulting from exposure to vinyl chloride, have been developed. The sensitivity and specificity of these antibodies have been determined by enzyme-linked immunosorbent assay (ELISA). The antibody to ethenoadenosine (1G4) reacts with both the ribose (50% inhibition at 600 fmol) and deoxyribose (50% inhibition at 980 fmol) form of the adduct. The antibody to ethenocytidine (6F5) also reacts with both the ribose (50% inhibition at 800 fmol) and deoxyribose (50% inhibition at 1000 fmol) form of the adduct. Neither antibody cross-reacts with non-modified DNA or the normal nucleotides. A more sensitive fluorescence ELISA was developed for antibody 1G4 with 50% inhibition at 212 fmol of ethenoadenosine and for antibody 6F5 with 50% inhibition at 192 fmol ethenocytidine. These antibodies have been used to determine the level of etheno derivatives in DNA modified in vitro with chloroacetaldehyde and in the DNA and RNA of cells treated in culture.

On the Flat-Band Potential of n-Type Cadmium Telluride in Alkaline Selenide, Polyselenide Electrolytes

The flat-band potential Efb of n-CdTe in alkaline K2Se solution was determined by the Mott-Schottky technique as a function of properties of the crystal and electrolyte. The experimental value, c.- 2.0 V v. s.c.e., is more negative than the value calculated by assuming the absence of localized surface charge, -0.35 V v. s.c.e. For a given electrolyte, Epb depended on the crystal orientation, and became more negative in the order (111), (110), (111). These results are consistent with specific adsorption of anionic selenide species on surface cadmium atoms. For a freshly prepared CdTe electrode, Efb depended on the selenide ion concentration in a Nernstian manner, consistent with sub-monolayer adsorption of HSe-. In contrast, when electrodes had been exposed to selenide electrolytes for several days, Efb was less dependent on the selenide ion concentration, in some cases being constant over four orders of magnitude of [Se2-]. Such results were consistent either with saturation of the surface with adsorbed ions, or with pinning. As the electrolyte was oxidized, Ub increased linearly with Eredox, reached a maximum value at -0.81 V v. s.c.e., and then decreased, so that neither the ideal model nor the Fermi level pinning model applied. Models which assumed adsorption only of HSe- were inconsistent with the observed behaviour, but the results were explained quantitatively by a model which assumed the competitive adsorption of HSe- and Se on the semiconductor surface. Such a model was consistent also with the independence of Efb and the total selenide concentration observed in some experiments. .The largest built-in potential observed was 1.23 V. An improved method of preparing CdTe electrodes is described.