Environmental organochlorine exposure and postmenopausal breast cancer risk.

Environmental exposure to organochlorine compounds has been associated with a potential role in breast cancer etiology, but results from previous investigations yielded inconsistent results. In this case-control study, we examined the effect of 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), hexachlorobenzene (HCB), mirex, and several measures of polychlorinated biphenyls (PCBs) on postmenopausal breast cancer risk. The study sample included 154 primary, incident, histologically confirmed, postmenopausal breast cancer cases and 192 postmenopausal community controls. Usual diet, reproductive and medical histories, and other lifestyle information was obtained by an extensive in person interview. Serum levels (ng/g) of DDE, HCB, mirex, and 73 PCB congeners were determined by gas chromatography with electron capture. PCB exposure was examined as total measured PCB levels, total number of detected PCB peaks, and three PCB congener groups. In the total sample, there was no evidence of an adverse effect of serum levels of DDE [odds ratio (OR), 1.34; 95% confidence interval (CI) 0.71-2.55], HCB (OR, 0.81; 95% CI, 0.43-1.53), or mirex (OR, 1.37; 95% CI, 0.78-2.39). Further, higher serum levels of total PCBs (OR, 1.14; 95% CI, 0.61-2.15), moderately chlorinated PCBs (OR, 1.37; 95% CI, 0.73-2.59), more highly chlorinated PCBs (OR, 1.19; 95% CI, 0.60-2.36), or greater number of detected peaks (OR, 1.34; 95% CI, 0.72-2.47) were not associated with increased risk. There was some indication of a modest increase in risk for women with detectable levels of less chlorinated PCBs (OR, 1.66; 95% CI, 1.07-2.88). Among parous women who had never lactated, there was some evidence for increased risk, associated with having detectable levels of mirex (OR, 2.42; 95% CI, 0.98-4.32), higher serum concentrations of total PCBs (OR, 2.87; 95% CI, 1.01-7.29), moderately chlorinated PCBs (OR, 3.57; 95% CI, 1.10-8.60), and greater numbers of detected PCB congeners (OR, 3.31; 95% CI, 1.04-11.3). These results suggest that an increase in risk of postmenopausal breast cancer associated with environmental exposure to PCBs and mirex, if at all present, is restricted to parous women who had never breast-fed an infant. Future studies should consider lactation history of participants, as well as use similar epidemiological and laboratory methodologies, to ensure comparability of results across studies.

Polychlorinated biphenyls, cytochrome P4501A1 polymorphism, and postmenopausal breast cancer risk.

In experimental systems, polychlorinated biphenyls (PCBs) induce cytochrome P4501A1 (CYP1A1), which is involved in metabolism of steroid hormones and polycyclic aromatic hydrocarbons in humans. A genetic polymorphism coding for a valine to isoleucine substitution in exon 7 has been associated with lung cancer risk in Japanese populations. In a previous study, we found no association between CYP1A1 genotype and breast cancer risk. However, we were interested in determining whether genotype would relate to risk when PCB body burden was taken into account. In a subset of a case-control study in western New York, 154 postmenopausal women with incident, primary, histologically confirmed postmenopausal breast cancer and 192 community controls were interviewed and underwent phlebotomy. Serum levels of 56 PCB peaks were determined by high resolution gas chromatography with electron capture. PCR-RFLP analyses of the CYP1A1 polymorphism were performed. Unconditional logistic regression was used to compute adjusted odds ratios and 95% confidence intervals. Among women with serum PCB levels above the median of the distribution in the control group, there was increased risk of breast cancer associated with the presence of at least one valine allele, compared with women who were homozygous for the isoleucine alleles (odds ratio, 2.93; 95% confidence interval, 1.17-7.36). Among women with low PCB body burden, no association between CYP1A1 genotype and breast cancer risk was observed. Adjustment for serum lipids and body mass index did not affect the magnitude of the observed associations. PCB body burden may modify the effect of the polymorphism on postmenopausal breast cancer risk through increased CYP1A1 enzyme induction or by activation by specific PCB congeners. These results should be considered preliminary, pending replication by other studies.

Tolerance to ethanol: effect of congeners present in bourbon.

Fish were exposed to water and to ethanol or bourbon solutions of the same ethanol concentration (0.1, 0.2, 0.4, 0.6, or 0.8 g/100 ml) during 6 h and then tested in 3.1 g/100 ml ethanol for loss of righting reflex or overturn point. The content of ethanol in the brain at overturn was determined for each fish. Although the ethanol brain levels at overturn of bourbon-exposed fish were higher than those of the ethanol group, no significant differences were observed between the two groups. Moreover, there was a tendency for the bourbon fish to take longer times to overturn than the ethanol fish. These findings indicate that the congeners present in bourbon did not affect significantly the development of tolerance to ethanol in goldfish.

Drug interactions in goldfish tolerant to ethanol and pentobarbital.

The interactions between short- and long-term exposure to ethanol and pentobarbital were characterized in goldfish tolerant to one of these drugs. The effects of ethanol and pentobarbital were measured by the overturn test as the time of onset of the loss of the righting reflex and the corresponding drug concentration in brain of fish immersed in 674 mumol/ml ethanol or 1.21 mumol/ml sodium pentobarbital (challenge solutions). The chronic treatment consisted of 6- or 24-h preexposure to 130 mumol/ml ethanol or 0.06 mumol/ml sodium pentobarbital in Tris buffer solution. Fish preexposed to ethanol for 6 or 24 h or to pentobarbital for 24 h were rendered more tolerant to pentobarbital or ethanol, respectively. Preexposure to pentobarbital for 6 h, however, produced in goldfish the same degree of tolerance to ethanol and to pentobarbital.

Ethanol and indomethacin interactions in motor impairment, hypnosis, and body temperature.

The actions of indomethacin on the effects produced by ethanol were determined in rats and mice by measuring motor coordination (Rotorod test), sleep times, and body temperatures. Mice receiving indomethacin in combination with ethanol slept shorter times than those receiving ethanol alone. The blood and brain ethanol concentrations at time of awakening were significantly higher in the mice receiving the combination of drugs. Ethanol actions on motor impairment in rats and mice and on hypothermia in mice were not altered by pharmacologically relevant doses of indomethacin. The data show that indomethacin antagonizes only some of the observed effects of ethanol. It is suggested that a common mechanism, such as prostaglandin synthesis, is not involved in the interactions of both drugs.

Renal pressor effect of ethanol in the isolated perfused rat kidney.

These experiments were performed to detect changes in renal function produced by acute infusions of small amounts of ethanol into the isolated kidney of the rat. Ethanol was infused for 10 min beginning at 40 min to reach a final concentration of approximately 80 mg/100 ml in the recirculating perfusate. Control kidneys were perfused for 90 min without the addition of ethanol. Control and ethanol infused kidneys were compared with respect to the following measurements: glomerular filtration rate, urine volume, urine protein concentration, pressure and fractional excretion of sodium, chloride, potassium, calcium and magnesium. Ethanol concentration in the perfusate was measured by gas chromatography. The only parameter affected by these concentrations of ethanol was pressure. During the ten min ethanol infusion, the pressure in the system rose significantly (P less than 0.01) from 110 +/- 0.3 to 120 +/- 2.8 mmHg. After the ethanol infusion, the pressure decreased towards pre-ethanol levels at a faster rate than the decrease in ethanol concentration in the perfusate.

A sensitive method for determining levels of [-]-2,5,-dimethoxy-4-methylamphetamine in the brain tissue.

INTRODUCTION: Indolamine and phenethylamine hallucinogens are drugs of abuse and, as well, mimic some aspects of idiopathic psychosis. To assist in investigating the mechanisms of action of (-)2,5-dimethoxy4-methylamphetamine ([-]-DOM), a member of the phenethylamine class of serotonergic hallucinogens, a sensitive and precise method for determining its levels in the brain tissue is required. METHODS: We now describe a method for determining nanogram quantities of [-]-DOM in the rat brain tissue using D-amphetamine as an intemal standard. The method employs solvent extraction with toluene and derivatization with trifluoroacetic acid anhydride (TFAA) followed by analysis using gas chromatography-mass spectrometry (GS-MS) in the selective ion monitoring (SIM) mode. RESULTS: With SIM detection, our overall recoveries were greater than 90%. The method was reliable in terms of within-day and between-day precision, accuracy, and linearity. The procedure was applied to animal subjects to determine the in vivo [-]-DOM brain levels following intraperitoneal (ip) administration. Our findings indicate that peak levels of [-]-DOM do not coincide with the 75-min pretreatment time established by drug-induced stimulus control. DISCUSSION: This study demonstrates a sensitive and precise analytical method for the determination of [-]-DOM levels in the rat brain following systemic administration of behaviorally relevant doses.

Alcohol-chlordiazepoxide interaction.

The effects of chlordiazepoxide (CDP) or its N-demethyl metabolite (NDCDP) on ethanol-induced sleep time were investigated. The results indicate that CDP or NDCDP produced a supra-additive effect on the duration of sleep time induced by ethanol. These effects were not due to an alteration in the rate of elimination of blood ethanol levels. Mice which were administered CDP/ethanol had significantly higher blood and brain CDP levels than mice injected with CDP alone. The increase in CDP concentrations could be partly responsible for the supra-additive prolongation of ethanol sleep time. Our results also indicate that NDCDP and/or its metabolites were largely responsible for the supra-additive effect, because mice injected with CDP/ethanol or NDCDP/ethanol (ethanol 4 g/kg: CDP or NDCDP, 10 mg/kg) showed comparable increases in sleep time, and the blood and brain levels of NDCDP were comparable in these two groups.

Influence of cefoperazone on ethanol and acetaldehyde metabolism in vitro.

The effect of cefoperazone on ethanol and acetaldehyde metabolism was studied in rat liver homogenates and with a purified aldehyde dehydrogenase. Rat liver homogenates were incubated with ethanol (30 mM) alone or in combination with cefoperazone (15 or 150 micrograms/g liver). Ethanol and acetaldehyde concentrations were determined at 6, 12, 18 and 24 minutes. Cefoperazone added to the incubation medium inhibited ethanol and acetaldehyde metabolism in a concentration-dependent manner. The addition of cefoperazone to rat liver homogenates incubated with acetaldehyde (300 microM), however, did not inhibit acetaldehyde disappearance for a period of 15 minutes. Purified aldehyde dehydrogenase was incubated with 300 microM acetaldehyde. When cefoperazone was added, acetaldehyde disappearance was significantly slower than without cefoperazone. The data indicate that cefoperazone inhibits ethanol metabolism in rat liver homogenates in a concentration-dependent manner. The effect of the antibiotic on acetaldehyde elimination in liver homogenate, however, depends on the concentration of acetaldehyde in the medium. The acetaldehyde dehydrogenase obtained from yeast is inhibited by cefoperazone.

Standardization of a method for the routine analysis of polychlorinated biphenyl congeners and selected pesticides in human serum and milk.

A methodology is presented for the routine determination of specific polychlorinated biphenyl (PCB) congeners in serum and milk samples. The procedures include standardized extraction, cleanup and quantitation by high-resolution gas chromatography (GC) and comprehensive quality assurance program to minimize systematic and erratic errors. The analyses of 68 PCB congeners and three pesticides, p,p1-dichloro diphenyl dichloro ethylene (DDE), hexachlorobenzene (HCB), and Mirex, at part-per-billion levels include the addition of surrogate congener standards (IUPAC isomers #46 and #142), extraction with hexane after protein precipitation, cleanup with Florisil, and analysis by GC with capillary column and electron capture detection. Quantitation is based on calibration standards and response factors using isomers #30 and #204 as internal standards. The quality control activities consist of analyses of samples in batches of 6 to 10 simultaneously with quality control (QC) samples. The quality assurance program checks that the procedures are under control by the use of control charts and set the criteria for data acceptability. The detection limits for the congeners and pesticides associated with the analyses of 500 serum samples and of 100 milk samples are reported. In addition, typical profiles of congener distribution in both matrices are illustrated.

Extracorporeal regional complexing haemodialysis treatment of acute inorganic mercury intoxication.

A 70-year-old white female presented approximately 24 h after ingesting three 475 mg tablets (1.425 g) of mercuric chloride in a suicide attempt. Acute renal failure necessitated the initiation of haemodialysis approximately 4 d after the ingestion. Treatment with BAL (2,3-dimercaptopropanol) resulted in only small increases in mercury output into dialysate. A new procedure involving the extracorporeal infusion of the chelating agent dimercaptosuccinic acid (DMSA) into the arterial blood line during haemodialysis was initiated. This procedure of Extracorporeal Regional Complexing Haemodialysis (ERCH) had been effective in increasing methylmercury removal in patients poisoned by contaminated grain. The first DMSA-ERCH procedure was performed 6 d after poisoning. There was a dramatic increase in mercury output into the dialysate. During three treatment sessions of 80 min each, 1189 micrograms of mercury were removed from the patient. The dialysed mercury represented the only mercury output since the patient was anuric and not producing faeces. DMSA-ERCH appears to be much more effective than BAL and haemodialysis in the treatment of acute inorganic mercury poisoning. The long interval between poisoning and initiation of treatment probably contributed to the patients ultimate demise, 28 d after poisoning. Efficacy of the DMSA-ERCH procedure for inorganic mercury poisoning is likely to be improved as the interval between exposure and treatment is reduced.

Environmental PCB exposure and risk of endometriosis.

BACKGROUND: Hormonally active environmental agents have recently been associated with the development of endometriosis. METHODS: We undertook a study to assess the relationship between endometriosis, an estrogen-dependent gynaecological disease, and 62 individual polychlorinated biphenyl (PCBs) congeners. We enrolled 84 eligible women aged 18-40 years undergoing laparoscopy for study, which included an interview and blood specimen (n=79; 94%). Thirty-two women had visually confirmed endometriosis at laparoscopy while 52 did not. Blood specimens were run in batches of 14 including four quality control samples for toxicological analysis. Each PCB congener was adjusted for recovery; batch-specific reagent blanks were subtracted. All PCB concentrations were log transformed and expressed in ng/g serum first as a sum and then as tertiles by purported estrogenic or anti-estrogenic activity of PCB congeners. RESULTS: Using unconditional logistic regression analysis, a significantly elevated odds ratio (OR) was observed for women in the third tertile of anti-estrogenic PCBs [OR 3.77; 95% confidence interval (CI) 1.12-12.68]. Risk remained elevated after controlling for gravidity, current cigarette smoking and serum lipids (OR 3.30; 95% CI 0.87-12.46). CONCLUSIONS: These data suggest that anti-estrogenic PCBs may be associated with the development of endometriosis.

Development of functional tolerance to pentobarbital in goldfish.

The acute effects of pentobarbital were measured by the times required for the loss of righting reflex (overturn point) and the pentobarbital brain concentration associated with the overturn. The test consisted of immersing the fish in a 0.3 mg/ml sodium pentobarbital in 0.1 M Tris buffer challenge solution until the overturn point was reached. To examine the development of tolerance the fish were pre-exposed to 0.1 M Tris buffer solutions containing 0.0, 0.010, 0.015 and 0.025 mg/ml of sodium pentobarbital for 6, 24 or 48 hr at which time the overturn times and the pentobarbital brain concentrations at overturn in the challenge solution were determined. The mean pentobarbital content in the brain at overturn of fish pre-exposed to 0.015 or 0.025 mg/ml solution was significantly higher (P less than .01) than in control fish. The loss of tolerance was determined at 3 hr after termination of the pre-exposure of the fish to the various pentobarbital solutions; tolerance was measured only in the group of animals pre-exposed to the 0.025 solution by the significant increase (P less than .01) in the pentobarbital brain levels over control fish. The equilibration curve for fish swimming in 0.025 mg/ml of sodium pentobarbital was determined for 48 hr. A steady state was attained within 6 hr with brain levels that reached approximately 80% the concentration of the external solution.

Indomethacin-ethanol interactions on acute inflammation.

The effect of ethanol on the anti-inflammatory actions of indomethacin was studied using carrageenan-induced edema in the paw of the rat as the test for acute inflammation. The agents were administered 1 hour prior to carrageenan injection, and the volume of the paw was measured immediately and at 3 and 5 hours after carrageenan. Ethanol at 1, 2, and 4 g/kg and indomethacin at 5 and 20 mg/kg significantly inhibited paw edema at 3 and 5 hours. The combination of the various doses of ethanol and indomethacin produced the same degree of inhibition as ethanol alone and significantly higher inhibition than indomethacin alone. The concentration of indomethacin in the inflammed paw was significantly higher than in the other paw in animals receiving 20 mg/kg indomethacin alone and 5 or 20 mg/kg indomethacin in combination with 2 g/kg ethanol. Ethanol co-administration significantly increased the concentration of indomethacin in the inflammed paw. Whether the observed interaction is due to increased concentration of indomethacin at the site of action or to direct interaction of ethanol and indomethacin in the inflammation process remains unclear.

Placental and fetal composition during the last trimester of gestation in the rat.

The composition of rat placentae or fetuses at Days 14, 17, and 21 of gestation and of 1-day-old pups was determined by measuring water, lipid, nonlipid, inorganic substances, and free amino acids. Placental weight significantly increased (P less than 0.05) from Day 14 to Day 21. The concentrations of amino acids in the placenta were as follows: 1) glutamic and aspartic acids decreased as gestation proceeded; 2) leucine, phenylalanine, tyrosine, and isoleucine reached a minimum on Day 17, while there were no differences between Days 14 and 21; 3) glycine, methionine, and phosphoserine attained a maximum on Day 14, followed by lower and constant concentrations on Days 17 and 21; and 4) serine, lysine, threonine, ethanolamine, valine, arginine, and ornithine remained constant. Fetal weight increased significantly (P less than 0.05) during the last week of gestation; no changes in body weight were observed from Day 21 of gestation to 24 h after birth. Fetal water concentration decreased significantly (P less than 0.05) and nonlipid concentration increased significantly (P less than 0.05) as gestation progressed; after birth, increased lipid and decreased water contents were observed. The concentration of each amino acid in the fetuses increased significantly (P less than 0.005) as gestation advanced except for alpha-aminobutyric acid which significantly decreased (P less than 0.001). There were no differences in the concentrations of amino acids between Day 21 fetuses and 1-day-old pups. The total amount of free amino acids in the rat fetuses increased significantly (P less than 0.001) after Day 17 of gestation. The measured changes in placental weight and composition were not correlated with the observed changes in the fetus. The amino acids measured at term in the rat placentae were present in the same relative amounts as reported for human placentae.

Ethanol-induced prenatal growth deficiency: changes in fetal body composition.

Ethanol (6 g/kg/day) produced intrauterine growth retardation (both body weight and length) in rat fetuses compared to pair-fed controls. Associated with this retardation was an increase in fetal body water and sodium content and a decrease in lipid-free solid content. Comparable electrolyte changes were not observed in maternal blood. These effects in fetal body content are not commonly observed in fetal malnutrition studies and are suggestive of a direct teratogenic effect of ethanol.

Ethanol and diazepam effects on intrauterine growth of the rat.

Four groups of 6 pregnant Long-Evans rats were intubated on days 6, 7, 9, 12, 15, and 18 of gestation with (a) 4 g/kg ethanol (E), (2) 10 mg/kg diazepam (D) plus isocaloric amounts of sucrose, (3) 10 mg/kg diazepam plus 4 g/kg ethanol (DE), and (4) gum arabic suspension plus sucrose solution in isocaloric amount with E (PF). All groups were pair-fed with group DE and had ad libitum access to water. On day 19 there were no differences in maternal weight gain, litter size, fetal weight, and protein content in fetal brain. Fetal brain and placental weight were significantly decreased in E, D, and DE. The decrease in placental weight in DE was significantly higher than in E or D. The concentrations of glutamic acid, alanine, glycine, serine, threonine, leucine, valine, and tyrosine in fetal brains were significantly decreased after E and D, but not different in DE from PF. Diazepam did not potentiate the effects of ethanol. Undernutrition could be a confounding factor in the observed effects.