Tissue distribution of (35)S-labelled perfluorooctane sulfonate (PFOS) in C57Bl/6 mice following late gestational exposure.

Exposure of rodents in utero to perfluorooctane sulfonate (PFOS) impairs perinatal development and survival. Following intravenous or gavage exposure of C57Bl/6 mouse dams on gestational day (GD) 16 to (35)S-PFOS (12.5mg/kg), we determined the distribution in dams, fetuses (GD18 and GD20) and pups (postnatal day 1, PND1) employing whole-body autoradiography and liquid scintillation counting. In dams, levels were highest in liver and lungs. After placental transfer, (35)S-PFOS was present on GD18 at 2-3 times higher levels in lungs, liver and kidneys than in maternal blood. In PND1 pups, levels in lungs were significantly higher than in GD18 fetuses. A heterogeneous distribution of (35)S-PFOS was observed in brains of fetuses and pups, with levels higher than in maternal brain. This first demonstration of substantial localization of PFOS to both perinatal and adult lungs is consistent with evidence describing the lung as a target for the toxicity of PFOS at these ages.

Clinical factors of importance for outcome after lumbar disc herniation surgery: long-term follow-up.

Factors as age, sex, smoking, duration of leg pain, working status, type/level of disc herniation and psychosocial factors have been demonstrated to be of importance for short-term results after lumbar discectomy. There are few studies with long-term follow-up. In this prospective study of lumbar disc herniation patients undergoing surgery, the result was evaluated at 2 and 5-10 (mean 7.3) years after surgery. Predictive factors for satisfaction with treatment and objective outcome were investigated. Out of the included 171 patients undergoing lumbar discectomy, 154 (90%) patients completed the 2-year follow-up and 140 (81%) completed the long-term follow-up. Baseline data and questionnaires about leg- and back pain intensity (VAS), duration of leg pain, disability (Oswestry Disability Index), depression (Zung Depression Scale), sick leave and employment status were obtained preoperatively, at 2-year- and long-term follow-up. Primary outcome included patient satisfaction with treatment (at both time points) and assessment of an independent observer at the 2-year follow-up. Secondary outcomes at 2-year follow-up were improvement of leg and back pain, working capacity and the need for analgesics or sleeping pills. In about 70% of the patients excellent or good overall result was reported at both follow-ups, with subjective outcome measurements. The objective evaluation after 2 years was in agreement with this result. Time on sick leave was found to be a clinically important predictor of the primary outcomes, with a potential of changing the probability of a satisfactory outcome (both objective and subjective) from around 50% (sick leave >3 months) to 80% (sick leave <2 months). Time on sick leave was also an important predictor for several of the secondary outcomes; e.g. working capacity and the need for analgesics.

Three-dimensional radiological classification of lumbar disc herniation in relation to surgical outcome.

Centrally located lumbar disc herniations have been reported to be of predictive value for poor post-operative clinical outcome. One hundred and fifty patients undergoing lumbar disc herniation surgery were prospectively included. Herniation-related parameters, including the grading of contours, were assessed from pre-operative computed tomography (CT) and magnetic resonance imaging (MRI) images using a new three-dimensional grading system. The radiological findings were compared with outcome parameters two years post-operatively (patient-assessed pain, function/health scores and evaluation by an independent observer). An intra- and inter-observer validation of the classification was performed in a subgroup of patients. High intra-observer and good inter-observer reliability for both CT and MRI was seen. In the study population, no relation between the distribution or size of the herniations and outcome at 2-year follow-up were found. The distribution and size of the lumbar disc herniations with the three-dimensional classification were not found to be of importance for the clinical outcome.

Peridural scar and its relation to clinical outcome: a randomised study on surgically treated lumbar disc herniation patients.

A prospective randomised 2-year follow-up study on patients undergoing lumbar disc herniation surgery. The objective was to investigate the relationship between peridural scarring and clinical outcome, the scar development 6 and 24 months postoperatively by using MRI, and if ADCON-L (a bioresorbable carbohydrate polymer gel) has an effect on scar size and/or improve patients' outcome after lumbar disc herniation surgery. The association between peridural scarring and recurrent pain after lumbar disc herniation surgery is debated. Numerous materials have been used in attempts to prevent or reduce postoperative peridural scarring; however, there are conflicting data regarding the clinical effects. The study included 119 patients whose mean age was 39 years (18-66); 51 (47%) were women. Sixty patients (56%) were perioperatively randomised to receive ADCON-L, and 48 (44%) served as controls. All patients underwent MRI at 6 and 24 months postoperatively, and an independent radiologist graded the size, location and development of the scar, by using a previously described scoring system. Pre- and 2-year postoperatively patients graded their leg pain on a visual analogue scale (VAS). At the 2-year follow-up patients rated their satisfaction with treatment (subjective outcome) and were evaluated by an independent neurologist (objective outcome), using MacNab score. There was no relationship between size or localisation of the scar and any of the clinical outcomes (VAS, subjective and objective outcome). The scar size decreased between 6 and 24 months in 49%, was unchanged in 42% and increased in 9% of the patients. Patients treated with ADCON-L did not demonstrate any adverse effects, nor did they demonstrate less scarring or better clinical outcome than control patients. No significant association between the presence of extensive peridural scar or localisation of scar formation and clinical outcome could be detected in the present study. Further, no positive or negative effects of ADCON-L used in disc herniation surgery could be seen.

Is increased segmental motion early after lumbar discectomy related to poor clinical outcome 5 years later?

The purpose of the study was to compare segmental motion in the early postoperative phase after lumbar discectomy to the outcome 5 years postoperatively. The study population had radiologically verified symptomatic L4-L5 or L5-S1 lumbar disc herniation and was referred with an indication for lumbar discectomy. Radiostereometry was performed in the supine and standing positions. The L4-L5 and L5-S1 segments were analysed separately. L4-L5 segments adjacent to the operated L5-S1 segment constituted a reference segment for the operated L4-L5 and vice versa. Twenty-one patients were available for the follow-up at 5 years. Outcome was classified as functionally good or poor. Repeated or planned repeat surgery at the same level during follow-up was considered as poor outcome. The L4-L5 segments in the poor group showed different direction of sagittal rotation (anterior versus posterior) of L4 on L5 compared with the good group (p<0.01). On the L5-S1 segment, patients with poor outcome displayed an increased anterior translation of about 1 mm (p<0.01) compared with the reference segments. Our study suggests that increased inducible vertebral displacement in the early postoperative phase after discectomy is associated with a poor clinical outcome.

The effect of standard lumbar discectomy on segmental motion: 5-year follow-up using radiostereometry.

We measured the effects of lumbar discectomy on segmental motion over a period of 5 years. Twenty-four patients with lumbar disc herniation were treated by standard lumbar discectomy at the L4-L5 or L5-S1 level. Peroperatively, tantalum markers were inserted into L4, L5, and the sacrum. Radiostereometric analysis was performed at discharge from hospital and 5 years postoperatively. The treated level was compared with the corresponding untreated level. Thus, patients who had discectomy at the L4-L5 level served as controls for patients with L5-S1 lesions and vice versa. The relative rotation and translation in relation to the three cardinal axes were calculated. Inducible displacements over the two discs were calculated between the supine and standing positions. At the L4-L5 level, there were no differences in inducible displacements between the operated and control levels at discharge or 5 years postoperatively. At the L5-S1 level we found decreasing inducible movement in the sagittal plane over time for discectomy patients. The reason for decreasing mobility over time after discectomy at the L5-S1 but not at the L4-L5 level is unknown. Mechanical factors caused by the more vertical orientation of the L5-S1 disc in combination with degenerative changes could be one explanation.

Distribution of bisphenol A and tetrabromobisphenol A in quail eggs, embryos and laying birds and studies on reproduction variables in adults following in ovo exposure.

In a previous study, we showed that bisphenol A (BPA) had oestrogen-like effects in bird embryos, causing malformations of the oviducts in Japanese quail (Coturnix japonica) and feminisation of the left testis in chicken (Gallus domesticus). In this study, uptake and distribution of BPA and tetrabromobisphenol A (TBBPA) in embryos and laying quail were examined as well as variables related to reproduction in adult quail following administration of the compounds into the yolk of embryonated eggs. The uptake of radiolabelled BPA, TBBPA and the reference compound diethylstilboestrol (DES) was studied in the embryos using beta-spectrometry. Autoradiography was employed to examine distribution in egg and embryo after yolk sac injection of BPA or TBBPA and in laying birds, following intravenous and oral administration. Following embryonic exposure to BPA or TBBPA, sexually mature male birds were examined for reproductive behaviour and testis morphology, and females were examined for egg laying and oviduct morphology. Neither BPA (200 microg/g egg) nor TBBPA (15 microg/g egg) caused any significant oestrogen-like effects on the variables studied, although effects on the female oviducts after BPA exposure were indicated. Embryonic exposure to DES is known to cause profound effects on male sexual behaviour and female oviduct morphology at doses 3-5 orders of magnitude lower than the BPA and TBBPA doses used in the present study. The proportions of BPA and TBBPA taken up by the embryos after yolk sac injection were similar to the proportion of DES taken up. Differences in bioavailability, therefore do not account for any major part of the potency differences between DES and the two bisphenol A compounds. The concentration of radioactivity in the embryo, as revealed by autoradiography, was low compared with that in the yolk at all stages studied (days 6, 10 and 15). Pronounced labelling of the bile and the allantoic fluid was observed, however, indicating that both compounds were readily metabolised and excreted. Radiolabelled BPA and TBBPA administered to laying quail were largely excreted via the bile and 9 days after oral dosing, only small amounts of the labelled compound remained within the body. Maternal transfer of labelled BPA and TBBPA to the egg was low.

Effects of bisphenol A and tetrabromobisphenol A on sex organ development in quail and chicken embryos.

The plastic monomere bisphenol A (BPA) and the flame retardant tetrabromobisphenol A (TBBPA) were examined for estrogen-like developmental effects on the reproductive organs in avian embryos. The synthetic estrogen diethylstilbestrol (DES) was used as a positive control. The test compounds were injected into the yolk of quail and chicken eggs early during incubation and the embryos were examined 2 d before anticipated hatching. At 200 microgram/g egg, BPA induced Müllerian duct (embryonic oviduct) malformation in female quail embryos and feminization of the left testis (ovotestis) in male chicken embryos. The estrogenic potency of BPA compared with DES was species and endpoint specific. Müllerian duct malformation was the most sensitive endpoint in quail embryos, whereas ovotestis formation was the most sensitive response in chicken embryos. Tetrabromobisphenol A caused high embryo mortality at 45 microgram/g egg in both species, but no estrogen-like effects were observed. Bisphenol A caused mortality only in chicken embryos at 67 and 200 microgram/g egg. To our knowledge, this is the first report on estrogen-like or embryolethal effects of BPA and TBBPA in birds.

Ecotoxicological risk assessment of environmental pollutants in the Arctic.

Concentrations of such persistent organic pollutants (POPs) as polychlorinated biphenyls (PCBs) are high in certain Arctic animal species. The polar bear, Arctic fox, and glaucous gull may be exposed to PCB levels above lowest-observed-adverse-effect-level (LOAEL) values for adverse effects on reproduction in mammals and birds. However, the dioxin-like congeners seem to be major contributors to the reproductive effects of PCBs and the relative concentrations of these congeners are low in polar bears. Temporal trends for POPs in Arctic wildlife and the sensitivities of Arctic species to these compounds determine the risk for future adverse health effects.

Sexual behavior in Japanese quail as a test end point for endocrine disruption: effects of in ovo exposure to ethinylestradiol and diethylstilbestrol.

Chemicals having a capacity to disturb the endocrine system have attracted considerable interest during recent years. There is a shortage of well-characterized in vivo tests with which to study such disturbances in different classes of vertebrates. In the present study, test end points related to reproduction in the Japanese quail were used to examine the estrogenic activity of chemicals. The synthetic estrogens ethinylestradiol (EE(2)) and diethylstilbestrol (DES), used as model compounds, were injected into the yolk of embryonated eggs. After the birds had been raised to sexual maturity, we examined sexual behavior, plasma testosterone concentrations, and testis morphology in adult males. The lowest doses resulting in a significantly depressed male sexual behavior were 6 ng/g egg for EE(2) and 19 ng/g egg for DES. Testis weight asymmetry was increased at 6 ng EE(2)/g egg, but DES had no effect at any treatment level. The area of the androgen-dependent cloacal gland was significantly reduced at 57 ng DES/g egg. No effects on plasma testosterone concentration or body weight following exposure to EE(2) or DES were observed at any dose level. Depressed male sexual behavior was the most sensitive of the end points studied, and we suggest that this ecologically relevant end point be included in avian in vivo testing for neuroendocrine disruptors.

The avian egg as a test system for endocrine disrupters: effects of diethylstilbestrol and ethynylestradiol on sex organ development.

Many environmental contaminants are known or suspected to interfere with hormonal function in animals. In vivo test methods to detect and characterize chemicals that disrupt the endocrine system are therefore urgently needed. In this study, we assessed the usefulness of abnormalities of the reproductive organs as test endpoints for estrogenic activity of xenobiotics in Japanese quail embryos. Two synthetic estrogens, diethylstilbestrol (DES) and ethynylestradiol (EE2), were injected into the yolks of embryonated eggs. At a dose as low as 2 ng EE2/g egg, all male embryos became feminized, containing ovary-like tissue in the left testis. The extent of feminization of the testes was determined by measuring the relative area of the ovary-like component. Persistent Müllerian ducts (oviducts) in male embryos, and malformations of the Müllerian ducts in females occurred at 2 ng EE2/g egg and higher doses. DES was approximately one-third to one-tenth as potent as EE2. The morphological changes studied were dose-dependent, indicating that they are useful as test endpoints for estrogenic activity. Feminization of the left testis in males proved to be the most sensitive endpoint. We propose the quail egg as a simple in vivo test system for estrogenic compounds.

Methods for studying xenoestrogenic effects in birds.

The embryonated bird egg provides a simple whole organism test system that allows examination of xenoestrogenic effects at different levels of biological organisation. Test compounds are injected into the yolk, the albumen or the air chamber at defined stages of embryonic development. Bioavailability and embryonic exposure may be determined by autoradiography and image analysis. Females represent the heterogametic sex (ZW) and estrogens determine differentiation into the female phenotype in birds. Xenoestrogenic effects can be examined by markers of gene expression and anatomical or histological characterization of the gonads and tubular sex organs. Chicks may be raised to sexual maturity and examination of sexual behaviour and reproductive physiology performed. The Japanese quail is a suitable test organism due to its small size and early sexual maturation.

EROD induction by environmental contaminants in avian embryo livers.

The CYP1A (EROD)-inducing potencies of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 3,3',4,4',5-pentachlorobiphenyl (PCB126) and benzo(k)fluoranthene (B(k)F) were studied in avian embryo livers. TCDD and PCB126 proved to be much more potent as inducers in the chicken than in the other species examined. This finding is consistent with a considerably higher sensitivity of the chicken compared with a number of other avian species to the embryotoxic effects of these compounds. Furthermore, the relative potencies of the tested Ah receptor agonists as CYP1A inducers differed substantially between species. B(k)F and PCB126 showed similar induction potencies in domestic duck embryos, whereas PCB126 is much more potent than B(k)F in the chicken. Also, the potency of PCB126, relative to that of TCDD, was much lower in quail embryo liver in vitro than in chicken embryo liver. Thus, there are large interspecific differences in birds in the sensitivity to CYP1A inducers and furthermore, the relative potencies of these compounds may differ substantially between species.