PCB Groups Research Articles

High quality diet attenuated the positive association between polychlorinated biphenyls and premature mortality among middle-aged and older adults

ObjectivePolychlorinated biphenyls (PCBs) have been reported to be a risk factor for premature death, while a high diet quality is thought to lower mortality risk. We aimed to examine whether PCBs were associated with higher all-cause and cause-specific mortality risk and whether such associations could be modified by the diet quality among US middle-aged and older adults. MethodsIncluded were 1259 participants aged 40 years or older from the 1999–2004 National Health and Nutrition Examination surveys. Exposure to PCBs was assessed in non-fasting serum samples, and mortality status was ascertained through December 31, 2019 using the public-use, linked mortality files. Diet quality was assessed using the Healthy Eating Index-2015 based on 24-h dietary recalls. Cox proportional hazard regression was applied to assess the associations of different PCB congener groups with mortality and the modifying effect by the diet quality. ResultsDuring a median follow-up of 17.75 years, 419 deaths occurred, including 131 from cardiovascular disease (CVD) and 102 from cancer. Serum concentrations of dioxin-like PCBs and non-dioxin-like PCBs were significantly associated with all-cause mortality, with hazard ratios (HRs) of 1.84 (95% confidence interval [CI], 1.10, 2.99) and 1.82 (1.09, 3.03) for extreme-tertile comparisons. A significant interaction was noted between dioxin-like PCBs and diet quality (P for interaction: 0.012), with a substantially more pronounced association among participants with a low diet quality (HR, 3.47; 95% CI: 1.29, 9.32), compared to those with a high diet quality (HR, 0.98; 95% CI: 0.40, 2.43). A similar weaker association was observed for total PCBs in participants with a high diet quality (P for interaction: 0.032). However, effect modifications by diet quality were not noted for the associations between different PCB groups and CVD mortality. ConclusionsWhile our findings need to be validated in other populations and mechanistic studies, they may suggest that a high quality diet could potentially attenuate the harmful effects of chronic PCB exposure.

The associations of prenatal exposure to dioxins and polychlorinated biphenyls with neurodevelopment at 6 Months of age: Multi-pollutant approaches

BackgroundPrenatal exposure to persistent organic pollutants, including polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (DL-PCBs), and nondioxin-like PCBs (NDL-PCBs), has been hypothesized to have a detrimental impact on neurodevelopment. However, the association of prenatal exposure to a dioxin and PCB mixture with neurodevelopment remains largely inconclusive partly because these chemical levels are correlated. ObjectivesWe aimed to elucidate the association of in utero exposure to a mixture of dioxins and PCBs with neurodevelopment measured at 6 months of age by applying multipollutant methods. MethodsA total of 514 pregnant women were recruited between July 2002 and October 2005 in the Sapporo cohort, Hokkaido Study on Environment and Children's Health. The concentrations of individual dioxin and PCB isomers were assessed in maternal peripheral blood during pregnancy. The mental and psychomotor development of the study participants' infants was evaluated using the Bayley Scales of Infant Development-2nd Edition (n = 259). To determine both the joint and individual associations of prenatal exposure to a dioxin and PCB mixture with infant neurodevelopment, Bayesian kernel machine regression (BKMR) and quantile-based g-computation were employed. ResultsSuggestive inverse associations were observed between in utero exposure to a dioxin and PCB mixture and infant psychomotor development in both the BKMR and quantile g-computation models. In contrast, we found no association of a dioxin and PCB mixture with mental development. When group-specific posterior inclusion probabilities were estimated, BKMR suggested prenatal exposure to mono-ortho PCBs as the more important contributing factors to early psychomotor development compared with the other dioxin or PCB groups. No evidence of nonlinear exposure-outcome relationships or interactions among the chemical mixtures was detected. ConclusionsApplying the two complementary statistical methods for chemical mixture analysis, we demonstrated limited evidence of inverse associations of prenatal exposure to dioxins and PCBs with infant psychomotor development.

Antibody Response of BNT162b2 and CoronaVac Platforms in Recovered Individuals Previously Infected by COVID-19 against SARS-CoV-2 Wild Type and Delta Variant.

Vaccinating recovered patients previously infected by COVID-19 with mRNA vaccines to boost their immune response against wild-type viruses (WT), we aimed to investigate whether vaccine platform and time of vaccination affect immunogenicity against the SARS-CoV-2 WT and Delta variant (DV). Convalescent patients infected by COVID-19 were recruited and received one booster dose of the BNT162b2 (PC-B) or CoronaVac (PC-C) vaccines, while SARS-CoV-2 naïve subjects received two doses of the BNT162b2 (CN-B) or CoronaVac (CN-C) vaccines. The neutralizing antibody in sera against the WT and DV was determined with live virus neutralization assay (vMN). The vMN geometric mean titre (GMT) against WT in recovered individuals previously infected by COVID-19 reduced significantly from 60.0 (95% confidence interval (CI), 46.5–77.4) to 33.9 (95% CI, 26.3–43.7) at 6 months post recovery. In the PC-B group, the BNT162b2 vaccine enhanced antibody response against WT and DV, with 22.3-fold and 20.4-fold increases, respectively. The PC-C group also showed 1.8-fold and 2.2-fold increases for WT and DV, respectively, after receiving the CoronaVac vaccine. There was a 10.6-fold increase in GMT in the CN-B group and a 1.3-fold increase in the CN-C group against DV after full vaccination. In both the PC-B and PC-C groups, there was no difference between GMT against WT and DV after vaccination. Subjects in the CN-B and CN-C groups showed inferior GMT against DV compared with GMT against WT after vaccination. In this study, one booster shot effectively enhanced the pre-existing neutralizing activity against WT and DV in recovered subjects.

The Association Between Pulmonary Contusion Severity and Respiratory Failure.

Pulmonary contusions (PCs) have historically been viewed as a serious complicating factor in thoracic injury. Recently, there has been conflicting evidence regarding the influence of PCs on outcomes; however, many studies do not stratify contusions by severity and may miss clinical associations. We sought to identify if contusion severity is associated with worse outcomes. A previously published chest wall injury database at an urban Level I trauma center was retrospectively reviewed. All severely injured subjects (defined as Injury Severity Score [ISS] ≥ 15) with moderate to severe thoracic injury (defined as a chest wall Abbreviated Injury Scale [AIS] ≥ 3) who required mechanical ventilation for > 24 h were stratified by contusion severity. Moderate to severe contusions were defined as AIS contusion ≥ 3 and Blunt Pulmonary Contusion 18 (BPC18) score ≥ 3. Over 5 y, 3,836 patients presented with chest wall injuries, of which 1,176 (30.6%) had concomitant contusions. When screened for inclusion criteria, 339 subjects with contusions and 211 subjects without contusions (no-PC) were identified. Of these, 234 had moderate to severe contusions defined by AIS contusion ≥ 3 (PC-A) and 230 had moderate to severe contusions by BPC18 ≥ 3 (PC-B). Compared to no-PC, both PC-A and PC-B groups had significantly lower mortality (17.9% and 17.4%, respectively, vs 28.9%); however, PC-A and PC-B groups had longer durations of mechanical ventilation (6 and 7 d, respectively, vs 5 d), longer ICU length of stay (10 and 10 vs 8 d), and longer overall hospital length of stay (15 and 15 vs 13 d). In severely injured polytrauma patients, PCs are seen with more severe chest injuries. Furthermore, moderate to severe contusions are associated with longer durations of mechanical ventilation, ICU length of stay, and hospital length of stay. Despite practice pattern changes, contusions appear to contribute significantly to the clinical course of the blunt chest wall injured patients.

Geochemical discrimination of basalts formed in major geodynamic settings

New tectonomagmatic discriminant diagrams are proposed to determine the geodynamic settings of basalt formation from geochemical data. The reference (training) sets, on which the diagrams are based, comprise (1) recent island-arc basalts (IAB, n = 2902); (2) within-plate basalts (WPB, n = 12379); (3) mid-ocean ridge basalts (MORB, n = 1828); and (4) postcollision basic rocks, including dikes and sills (PCB, n = 1823). To determine the geodynamic settings of basalt formation, the belonging of a tested object to one of WPB + PCB, MORB, or IAB + PCB groups is first established, and then PCB is discriminated from WPB or IAB. The average weighted uncertainty of IAB, MORB, and WPB identification is about 10%. The use of new diagrams results in a substantial decrease in classification errors as compared with previously elaborated plots.

TCT-72 PCI Lesion Morphology According to Chronic Statin Use: An ADAPT-DES IVUS Substudy

drug-eluting stent (DES) implantation. Methods: Between July 2008 and May 2012, we performed PCI for 321 ISR lesions using POBA (67 lesions, POBA group), PCB (149 lesions, PCB group), and DES (105 lesions, DES group). The morphological assessment of neointimal tissue at the minimum lumen area site as to restenotic tissue structure (homogeneous, heterogeneous, or layered type) using OCT was performed. We examined the association between tissue structure and mid-term (6-8 months) results including ISR and target lesion revascularization (TLR) rates. Results: The patients were 263 men and 58 women, and the mean age was 68.9 9.6 years. The mean follow-up period was 209 38 days. The association of tissue structure with ISR and TLR rates in each groups is shown in the figure. The ISR rates of lesions with homogeneous and layered structure were significantly lower in the PCB and DES groups than in the POBA group, whereas there were no differences between 3 groups in heterogeneous structure.

Adipose tissue PCB levels and CYP1B1 and COMT genotypes in relation to breast cancer risk in postmenopausal Danish women

Exposure to PCBs may be an etiologic factor for breast cancer. The cytochrome P450 1B1 (CYP1B1) and catechol-O-methyltransferase (COMT) enzymes are involved in estrogen metabolism and PCB metabolism, both of which may relate to breast cancer susceptibility. Polymorphisms in genes regulating these enzymes control efficiency. Our objective was to assess whether CYP1B1 and COMT gene polymorphisms modulate the effect of PCBs in breast cancer risk, among postmenopausal Danish women. Neither CYP1B1 Leu432Val polymorphisms nor adipose tissue PCBs were independently associated with breast cancer risk. When assessing the independent effect of the COMT Val158Met polymorphism, we observed reduced risk for breast cancer amongst hormone replacement therapy using women who were homozygous carriers of the variant allele compared with those carrying the wild-type variant (RR = 0.41; 95% CI: 0.29–0.89). We found no statistically significant interactions between any of the PCB groups and CYP1B1 or COMT polymorphisms on the risk of breast cancer.

Effect of autologous platelet-rich plasma on the repair of full-thickness articular defects in rabbits

To assess the effect of autologous platelet-rich plasma on the repair of full-thickness articular cartilage lesions in immature rabbits. To that end, the samples were studied using macroscopic, microscopic and biomechanical techniques. Twenty-four 11-week-old New Zealand rabbits were divided into two groups based on the treatment (physiological saline serum PCB, autologous platelet-rich plasma PRP). Cartilage lesions were drilled in medial femoral condyle of these rabbits. Other 12 rabbits were under the same conditions, but they did not suffer any lesion and treatment (control group CTR). The three groups were divided into two subgroups, depending on the age at the time of killing (16 and 19weeks old). The CTR group showed the best possible value in the macroscopic and microscopic evaluation. Meanwhile, the PCB and PRP group values were lower than the CTR group values, at two times of the study, but similar to each other at 19weeks. In the biomechanical study, at 16weeks, the CTR and PCB groups behaved similarly, with values above PRP group values, while at 19weeks, CTR group showed higher values than PCB and PRP groups, and there were no differences between these values. The evolution of the tissue treated with autologous PRP showed a positive tendency over time, while the PCB group was negative. Nevertheless, at 19weeks of age, the PRP treatment did not show better results than the PCB, both showing the characteristics of fibrocartilaginous tissue. Likewise, none of the two treatments produced a repair tissue as the healthy cartilage.

N-acetylcysteine (NAC) diminishes the severity of PCB 126-induced fatty liver in male rodents

Potent aryl hydrocarbon receptor agonists like PCB 126 (3,3′,4,4′,5-pentachlorobiphenyl) cause oxidative stress and liver pathology, including fatty liver. Our question was whether dietary supplementation with N-acetylcysteine (NAC), an antioxidant, can prevent these adverse changes. Male Sprague-Dawley rats were fed a standard AIN-93G diet (sufficient in cysteine) or a modified diet supplemented with 1.0% NAC. After one week, rats on each diet were exposed to 0, 1, or 5μmol/kg body weight PCB 126 by i.p. injection (6 rats per group) and euthanized two weeks later. PCB-treatment caused a dose-dependent reduction in growth, feed consumption, relative thymus weight, total glutathione and glutathione disulfide (GSSG), while relative liver weight, glutathione transferase activity and hepatic lipid content were dose-dependently increased with PCB dose. Histologic examination of liver tissue showed PCB 126-induced hepatocellular steatosis with dose dependent increase in lipid deposition and distribution. Dietary NAC resulted in a reduction in hepatocellular lipid in both PCB groups. This effect was confirmed by gravimetric analysis of extracted lipids. Expression of CD36, a scavenger receptor involved in regulating hepatic fatty acid uptake, was reduced with high dose PCB treatment but unaltered in PCB-treated rats on NAC-supplemented diet. These results demonstrate that NAC has a protective effect against hepatic lipid accumulation in rats exposed to PCB 126. The mechanism of this protective effect appears to be independent of NAC as a source of cysteine/precursor of glutathione.

Differential gene expression and a functional analysis of PCB-exposed children: Understanding disease and disorder development

The goal of the present study is to understand the probable molecular mechanism of toxicities and the associated pathways related to observed pathophysiology in high PCB-exposed populations. We have performed a microarray-based differential gene expression analysis of children (mean age 46.1months) of Central European descent from Slovak Republic in a well-defined study cohort. The subset of children having high blood PCB concentrations (>75 percentile) were compared against their low PCB counterparts (<25 percentile), with mean lipid-adjusted PCB values of 3.02±1.3 and 0.06±0.03ng/mg of serum lipid, for the two groups, respectively (18.1±4.4 and 0.3±0.1ng/ml of serum). The microarray was conducted with the total RNA from the peripheral blood mononuclear cells of the children using an Affymetrix platform (GeneChip Human genome U133 Plus 2.0 Array) and was analyzed by Gene Spring (GX 10.0). A highly significant set of 162 differentially expressed genes between high and low PCB groups (p value <0.00001) were identified and subsequently analyzed using the Ingenuity Pathway Analysis tool. The results indicate that Cell-To-Cell Signaling and Interaction, Cellular Movement, Cell Signaling, Molecular Transport, and Vitamin and Mineral Metabolism were the major molecular and cellular functions associated with the differentially altered gene set in high PCB-exposed children. The differential gene expressions appeared to play a pivotal role in the development of probable diseases and disorders, including cardiovascular disease and cancer, in the PCB-exposed population. The analyses also pointed out possible organ-specific effects, e.g., cardiotoxicity, hepatotoxicity and nephrotoxicity, in high PCB-exposed subjects. A few notable genes, such as BCL2, PON1, and ITGB1, were significantly altered in our study, and the related pathway analysis explained their plausible involvement in the respective disease processes, as mentioned. Our results provided insight into understanding the associated molecular mechanisms of complex gene–environment interactions in a PCB-exposed population. Future endeavors of supervised genotyping of pathway-specific molecular epidemiological studies and population biomarker validations are already underway to reveal individual risk factors in these PCB-exposed populations.

Pemetrexed in the treatment of malignant mesothelioma: Results from an expanded access program in Germany

An international expanded access program was initiated to provide access to treatment with pemetrexed prior registration and reimbursement for malignant mesothelioma (MM). Chemonaïve and pretreated patients with inoperable MM of the pleura or peritoneum were eligible. This report describes the results obtained in German centers. Investigators could choose between three treatments: Pemetrexed 500 mg/m(2) alone (P) or in combination with cisplatin 75 mg/m(2) (PC) or carboplatin AUC 5 (PCb). From November 2002 to June 2004, a total of 567 patients (554 with pleural MM; 41% pretreated) were included. Of 548 evaluable patients with pleural MM, 191 received P, 137 PC and 220 PCb. Patients in the P group were more often pretreated (70%) and had worse performance status compared with the other groups. In the P, PC, and PCb groups overall response rate (ORR) was 16%, 24% and 18%, median time to progression (TTP) was 5.5, 8.2, and 6.9 months, and median overall survival (OS) was 8.7, 11.3 and 9.7 months respectively. Efficacy outcomes were better for chemonaïve than for pretreated patients, and P was less hematotoxic than PC or PCb. Treatment of pleural MM with pemetrexed alone or in combination with platinum was safe and active as first and second-line therapy.

Sorption of very hydrophobic organic compounds (VHOCs) on dissolved humic organic matter (DOM). 2. Measurement of sorption and application of a Flory-Huggins concept to interpret the data.

Sorption phenomena of very hydrophobic compounds (VHOCs, log K(OW) > 5) on dissolved humic organic matter (DOM) are overwhelmingly based on partitioning processes. In this respect, DOM is very similar to "rubbery" soil/sediment OM. To exclude system adsorption effects, the DOM sorption coefficients (K(DOM)) of VHOCs were determined using a dynamic approach based on the VHOCs' aqueous solubility enhancement in the presence of DOM. Partition coefficients are strongly correlated to the analytes' Kow across the alkane, PAH, and PCB groups under study. These three "families" are regarded to be good models of hydrophobic partitioning. On the basis of a uniform one-parameter concept characterizing sorption on amorphous polymers, Hildebrand solubility parameters of amorphous polymeric sorbents, including DOM, and of sorbates can be calculated on the basis of partition coefficients. Likewise, partition coefficients can be estimated using Hildebrand solubility parameters. Literature-based partition coefficients on DOM fit very well in this universal one-parameter concept. On using our own sorption data of PAHs, PCBs, and alkanes on DOM, an almost identical solubility parameter for the DOM polymer under study is obtained. The concept is also very useful in understanding both waterborne and airborne bioconcentration processes, which are considered to be partitioning phenomena.

Effects on developmental landmarks and reproductive capability of 3,3',4,4'-tetrachlorobiphenyl and 3,3',4,4',5-pentachlorobiphenyl in offspring of rats exposed during pregnancy.

1. Pregnant Wistar rats were treated orally with a single dose of 100 microg 3,3',4,4'-tetrachlorobiphenyl (PCB 77)/kg b.w. or 10 microg 3,3',4,4',5 pentachlorobiphenyl (PCB 126)/kg b.w. on day 15 of pregnancy. The control rats received peanut oil at the same day. Developmental landmarks were assessed in all offspring rats and reproductive effects of PCB 77 and PCB 126 on male offspring were studied on postnatal day 65 (at puberty) and on postnatal day 140 (at adulthood). 2. The ano-genital distance as well as the ratio ano-genital distance to body length was reduced in male pups of the PCB 126 group and the age at vaginal opening was significantly delayed in the female pups. 3. Testis, brain weights and daily sperm production were permanently increased and seminal vesicle weights were decreased in male offspring of the PCB 77 group. In male rats of PCB 126 group, the brain weights were permanently increased and ventral prostate weights permanently reduced. In both PCB groups, however, serum testosterone concentration was reduced only at adulthood. Additionally, the male rats of the PCB 126 group showed alterations in sexual behavior. In these rats the number of mounts with intromissions was significantly increased. 4. The results of this study show that PCB 126 elicits some TCDD-like reproductive effects after in utero exposure, while the reproductive effects of in utero exposure to PCB 77 on male offspring may be attributed to the neonatal hypothyroidism induced by the substance during early fetal development. Further studies using multiple doses and providing thyroid hormone data will be necessary to support this hypothesis.

Organochlorine pesticide residue and PCBs in harbour porpoise ( Phocoena phocoena) incidentally caught in Scandinavian waters

During Norwegian and Danish harbour porpoise projects 1987–1991, subcutaneous blubber samples of 34 male harbour porpoises ( Phocoena phocoena) were collected. Animals from three geographical locations, ranging from 56°N, 12°E to 71°N, 26°E, were chosen in order to study the organochlorine (OC) contamination in this species inhabiting the northeastern part of the North Atlantic Ocean, the northern North Sea and Kattegat, at the locations of Tufjord, Vestlandet and Gilleleje, respectively. Analytical standards used consisted of the industrial chemicals PCBs (22 individual PCB congeners and 6 industrial mixtures which contained 104 PCB congeners or group of congeners) and HCB, and the organochlorine pesticides DDT, HCH, the cyclodienes endrin, dieldrin and the chlordane metabolites oxychlordane and trans-nonachlor, and heptachlor epoxide. A total of 16 PCB congeners or groups of congeners, all the DDT metabolites except o,p'-DDD, and all the pesticides were detected in all animals. The concentrations of ∑PCB (sum of concentrations of 47 detected PCB congeners) and ∑DDT (sum of concentrations of all DDT detected compounds) ranged from 3·7–65·3 and 3·2–45·0 μg g −1 lipid weight, respectively. The range of mean concentrations of dieldrin, endrin and trans-nonachlor was 1–3 μg g −1, while mean concentrations of HCHs, heptachlor epoxide, and HCB were <1 μg g −1. No significant variation in PCB congener pattern was apparent between geographical areas. The major PCB congeners nos 147/123, 153, 138/163/164, 182/187 and 180 at Gilleleje, Vestlandet and Tufjord represented 53%, 45% and 44% of ∑PCB, respectively. A significant difference was found between the number of PCB congeners in blubber of newborn and older porpoises. This might indicate the presence of a blood/placenta barrier and/or selective mammary transport of PCBs with specific structures. A significant OC accumulation with age was apparent, with the exception of HCB and HCHs. Geographical differences in the levels of OCs were apparent for all compounds except for dieldrin and heptachlor epoxide. Significantly higher levels of chlordane metabolites ( trans-nonachlor and oxychlordane) and endrin were found in the group of animals from the northern location Tufjord, while ∑DDT, p,p'-DDTs, HCHs and PCBs were highest in the group of animals from the southern location Gilleleje. Highest levels of the o,p'-substituted DDTs were found in specimens from the middle location Vestlandet. These findings indicate little or no regular migration of harbour porpoise between these three locations. No correlations were found between OC concentrations and blubber thickness. Although mean values of ∑DDT and ∑PCB were in the lower end of previously reported levels in harbour porpoise from adjacent waters in the eastern part of the North Atlantic Ocean and along the coasts of North America, these levels are relatively high. The organochlorine concentrations in harbour porpoises in the present study were 2–3 times higher than corresponding OC levels detected in harbour seals ( Phoca vitulina) from the same areas.

Determination of traces of polychlorinated biphenyls in pigments

AbstractPCB patterns in a new pigment brand are characterized using GC‐MS in the single ion monitoring (SIM) mode. Specific PCBs are then used as external standards for GC‐ECD quantification. The following PCB isomers or groups of isomers have to be determined (CB = chlorobiphenyl): total diCBs, 3,3′ diCB, 2,4,5‐triCB, 2,2′,4,4′‐tetraCB, 2,2′,5,5′‐tetraCB, total pentaCB, total hexaCB. Capillary gas chromatography is performed on preseparated solutions (LC) of pigment. An electron caputure detector (ECD) is used for PCB detection and quantification. Calibration is based on the peak areas of external standards and the PCB isomers in the samples, all normalized for internal standard peak areas. Total concentrations of diCB, hexaCB, or pentaCB in a sample are calculated by summing the individual PCB isomer concentrations within the correcsponding elution ranges. Determination limits lie in the range of 1 mg/PCB‐isomer/kg pigment.

Effects of PCBs on gonads, sex hormone balance and reproduction processes of Japanese quail Coturnix coturnix japonica after ingestion during sexual maturation

Male and female Japanese quail were fed PCB (Clophen A 60) in concentrations of 0, 50, 100 and 150 ppm for three weeks during the maturation period (second to fourth weeks of life). The effects of PCB on gondal histology, on sex hormone concentrations in plasma and gonads and on plasma calcium levels were investigated. PCB effects on subsequent reproductive processes were measured by evaluating laying capacity, egg, eggshell and semen analysis. In females, no PCB effects were detected on ovary and oviduct weight, nuclear volume and lipid content of the thecal gland cells and on plasma 17 β-oestradiol and calcium content. However, liver weights were increased in all PCB-treated groups. PCB caused delayed laying and a diminished laying capacity. Egg and shell weights were either not affected by PCB treatment or were higher in PCB groups. The breaking strength of the eggs was reduced after PCB ingestion. In males, PCB treatment resulted in a trend towards reduced testis weights, in a significantly decreased amount of the testes' seminiferous epithelium and in a smaller nuclear volume of the Leydig cells. The lipid content of the latter was not affected and plasma calcium levels were unchanged. Liver weights in all treatment groups were increased. Plasma concentrations of testosterone (T) and 5 α-dihydrotestosterone (DHT) were not affected by PCB, nor was the DHT content in the testes. T levels in testes were significantly higher after 50 ppm treatment. PCB showed no effect on the percentage of dead spermatozoa in the ejaculates. In another experiment, which consisted of feeding 0 and 150 ppm Clophen, beginning in the first week of life, plasma sex hormone concentrations were measured during the whole experiment from day 24 to day 42 of life. In females, progesterone levels were not greatly affected by PCB but 17 β-oestradiol appeared to be lower before sexual maturity and was more unstable in the PCB group when egg laying occurred. In males, T concentrations were not significantly altered, nor were DHT plasma levels.

Antibody Response and Reduction in Bursa of Fabricius and Spleen Weights of Progeny of Chickens Fed PCBs

In Experiment 1, polychlorinated biphenyls (Aroclors 1016, 1232, 1242, 1248, and 1254) were fed ad libitum to White Leghorn chickens at dietary levels of 5, 10, and 20 p.p.m. for 8 weeks. Hatchability of eggs from hens fed 10 and 20 p.p.m. of Aroclors 1232, 1242, and 1248 was reduced. The weights of the spleen and bursa of Fabricius of day-old chicks from hens fed 10 p.p.m. of Aroclors 1242 and 1248 or 20 p.p.m. of Aroclors 1232, 1242, 1248, and 1254 were less than those of control chicks. At 3 weeks of age these organ weights were still less than those of the control chicks. Body weights were similar to those of controls at hatching, but the 3 week weight gains of progeny from hens fed 20 p.p.m. Aroclors 1242 and 1248 were less than gains of control progeny. After replacement of the PCB diet with uncontaminated feed, hatchability improved within 2 weeks and by 8 weeks was similar to that of the controls. Bursa weight of the progeny was the only parameter still reduced after the hens were fed uncontaminated feed.In Experiment 2, hens were fed 10 p.p.m. 1248 ad libitum for 8 weeks. The progeny bursa weights were reduced, but the treatment did not interfere with antibody production. PCB treatment had no effect on antibody production after primary or secondary challenges with Brucella abortus. However, after the primary challenge, bursectomized birds of both the control and PCB groups produced significantly fewer antibodies than the nonbursectomized birds. Differential accumulations of the polychlorinated biphenyls occurred in the egg. Chlorinated biphenyls with relative retention times less than that of DDE accumulated to less than one-half of the dietary concentration whereas chlorinated biphenyls with retention times greater than that of DDE accumulated in the egg to a concentration equivalent to the dietary concentration.