In vitro estrogenicity of polybrominated diphenyl ethers, hydroxylated PDBEs, and polybrominated bisphenol A compounds

Polybrominated diphenyl ethers (PBDEs) are used in large quantities as additive flame retardants in plastics and textile materials. PBDEs are persistent compounds and have been detected in wildlife and in human adipose tissue and plasma samples. In this study, we investigated the (anti)estrogenic potencies of several PBDE congeners, three hydroxylated PBDEs (HO-PBDEs), and differently brominated bisphenol A compounds in three different cell line assays based on estrogen receptor (ER)-dependent luciferase reporter gene expression. In human T47D breast cancer cells stably transfected with an estrogen-responsive luciferase reporter gene construct (pEREtata-Luc), 11 PBDEs showed estrogenic potencies, with concentrations leading to 50% induction (EC(50)) varying from 2.5 to 7.3 microM. The luciferase induction of the most potent HO-PBDE [2-bromo-4-(2,4,6-tribromophenoxy)phenol] exceeded that of estradiol (E(2)), though at concentrations 50,000 times higher. As expected, brominated bisphenol A compounds with the lowest degree of bromination showed highest estrogenic potencies (EC(50) values of 0.5 microM for 3-monobromobisphenol A). In an ER alpha-specific, stably transfected human embryonic kidney cell line (293-ER alpha-Luc), the HO-PBDE 4-(2,4,6-tribromophenoxy)phenol was a highly potent estrogen with an EC(50) < 0.1 microM and a maximum 35- to 40-fold induction, which was similar to E(2). In an analogous ER beta-specific 293-ER betas-Luc cell line, the agonistic potency of the 4-(2,4,6-tribromophenoxy)phenol was much lower (maximum 50% induction compared to E(2)), but EC(50) values were comparable. These results indicate that several pure PBDE congeners, but especially HO-PBDEs and brominated bisphenol A-analogs, are agonists of both ER alpha and ER beta receptors, thus stimulating ER-mediated luciferase induction in vitro. These data also suggest that in vivo metabolism of PBDEs may produce more potent pseudoestrogens.

Plasma levels of persistent organohalogens and hormone levels in adult male humans

In this study the authors assessed the possible relationship between high dietary exposure to persistent organohalogens (OHS) through fatty fish from the Baltic Sea and hormone levels in adult men. Blood samples were drawn from 110 men who consumed varying amounts of fish (i.e., 0-32 meals per month) for analysis of plasma levels of 18 polychlorinated biphenyl (PCB) congeners, 5 hydroxy-PCBs, 1,1,1-trichloro-2,2-bis(4-chlorophenyl)-ethane (p,p'-DDT), 1,1-dichloro-2,2-bis(4-chlorophenyl)-ethene (p,p'-DDE), hexachlorobenzene, and 2,2',4,4'-tetrabromodiphenyl ether. In addition, plasma levels of follicle-stimulating hormone, luteinizing hormone, prolactin, plasma thyrotropin, free and total T3, free and total T4, and free testosterone were analyzed. The authors adjusted for age, and the only significant associations that remained were negative correlations between 2,2',4,4'-tetrabromodiphenyl ether and plasma thyrotropin (p < .001), and between pentachlorophenol and follicle-stimulating hormone (p = .04). The authors expected that there would be some significant correlations that resulted from pure chance. High consumption of organohalogen-polluted fish did not appear to affect plasma concentrations of pituitary, thyroid, or testosterone hormone levels in male adults.

Irreversible binding and adrenocorticolytic activity of the DDT metabolite 3-methylsulfonyl-DDE examined in tissue-slice culture

The persistent adrenocorticolytic DDT metabolite 3-methylsulfonyl-DDE (MeSO(2)-DDE) was originally identified in Baltic grey seals, a population suffering from adrenocortical hyperplasia. In mice, MeSO(2)-DDE induces mitochondrial degeneration and cellular necrosis in the adrenal zona fasciculata. In this study, we used precision-cut tissue slice culture to examine local CYP11B1-catalyzed irreversible binding of MeSO(2)-DDE in the murine adrenal cortex. We also examined effects on steroid hormone secretion, histology, and ultrastructure. As determined by microautoradiography, selective binding occurred in zona fasciculata of slices exposed to MeSO(2)-[(14)C]-DDE. Quantification of binding by phosphorautoradiography revealed a 3-fold reduction of binding in slices co-exposed to the CYP11B1 inhibitor metyrapone. As measured by HPLC, corticosterone and 11-deoxycorticosterone secretion to the medium increased linearly for at least 24 hr. Addition of the ACTH analog tetracosactide caused an 8-fold increase in corticosterone secretion. Addition of metyrapone reduced corticosterone secretion 4-fold. Exposure of slices to MeSO(2)-DDE (50 microM) reduced the rate of corticosterone secretion by 90% after 24 hr of incubation. As determined by electron microscopy, vacuolated mitochondria were present in zona fasciculata of slices exposed to MeSO(2)-DDE (50 microM) for 24 hr. Our findings show that all effects of MeSO(2)-DDE previously reported in vivo could be reproduced in adrenal slice culture ex vivo. This test system allows analysis of zone-specific irreversible binding and effects on steroid hormone secretion and target cell ultrastructure. We propose adrenal slice culture as a simple ex vivo test system with which to examine the adrenocorticolytic activity of xenobiotics in human and wild animal tissue.

PCB methyl sulphones in rat liver after exposure to PCB (Clophen A50): analysis and radiosynthesis of selected methylsulphonyl-PCBs

1. The hepatic metabolism of polychlorinated biphenyls (PCBs) and formation of PCB methyl sulphone metabolites (MeSO2-PCBs) was determined in the male Sprague Dawley rat 1, 2, 4 or 8 weeks after dosage with Clophen A50 (a commercial PCB mixture). 2. The total concentration of the PCB congeners examined (sigmaPCB) decreased during the experimental period, from 40 microg g(-1) lipid (l.w.) after 1 week to 4 microg g(-1) l.w. after 8 weeks. A 50% decrease of PCB in the liver were estimated to be 28, 13 and 11 days for 2,2',4,4',5,5'-hexachlorobiphenyl (CB153), 2,2',3,3',4,4',5-heptaCB (CB170) and 2,2'3,4',5,5',6-heptaCB (CB187), respectively. 3. The total MeSO2-PCB (sigmaMeSO2-PCB) concentration increased from 800 to 1,020 ng g(-1) l.w. during the first 2 weeks of treatment and thereafter a decrease to 120 ng g(-1) l.w. after 8 weeks. The relative concentration of both 3'-MeSO2-2,2',4,4',5-pentaCB (3'-MeSO2-CB101) and 3'-MeSO2-2,2',3,4,5'-pentaCB (3'-MeSO2-CB87) in rat liver showed significant increases during the 8 weeks. In contrast, the relative concentrations of 4-MeSO2-2,4',5,5-tetraCB (4-MeSO2-CB64), 3-MeSO2-2,3',4',5-tetraCB (3-MeSO2-CB70) and 4-MeSO2-2,2',3,4,5',6'-hexaCB (4'-MeSO2-CB132) decreased significantly. 4. A route for the synthesis of radiolabelled MeSO2-PCBs was developed employing the 'Pummerer reaction' to convert methylthio-PCBs (MeS-PCBs) to the corresponding mercapto-PCBs (SH-PCB). The SH-PCBs were methylated with radiolabelled methyl iodide and the resulting sulphides oxidized to yield the corresponding MeSO2-PCBs. Using this approach, 3-[14C]-MeSO2-2,2',4',5,5',6-hexaCB (3-[14C]-MeSO2-CB149), 4-[14C]-MeSO2-2,2',4',5,5',6-hexaCB (4-[14C]-MeSO,-CB149), 3'-[14C]-MeSO2-CB101, 4'-[14C]-MeSO2-2,2',4,5,5'-pentaCB (4'-[14C]-MeSO2-CB101) and 4'-[3H]-MeSO2-CB101 were synthesized in quantitative radiochemical yields.

Flame retardants in indoor air at an electronics recycling plant and at other work environments

Air samples from a plant engaged in recycling electronics goods, a factory assembling printed circuit boards, a computer repair facility, offices equipped with computers, and outdoor air have been analyzed with respect to their content of brominated hydrocarbon and phosphate ester flame retardants. Polybrominated diphenyl ethers, polybrominated biphenyls, 1,2-bis(2,4,6-tribromophenoxy)-ethane, tetrabromobisphenol A, and organophosphate esters were all detected in the indoor air samples, with the highest concentrations being detected in air from the recycling plant. In air from the dismantling hall at the recycling plant the average concentrations of decabromodiphenyl ether, tetrabromobisphenol A, and triphenyl phosphate were 38, 55, and 58 pmol/m3, respectively. Significantly higher levels of all of these additives were present in air in the vicinity of the shredder at the dismantling plant. This is the first time that 1,2-bis(2,4,6-tribromophenoxy)-ethane and several arylated phosphate esters are reported to be contaminants of air in occupational settings. At all of the other sites investigated, low levels of flame retardants were detected in the indoor air. Flame retardants associated with airborne particles, present at elevated levels, pose a potential health hazard to the exposed workers.

Contribution of planar (0-1 ortho) and nonplanar (2-4 ortho) fractions of Aroclor 1260 to the induction of altered hepatic foci in female Sprague-Dawley rats

The hepatic tumor promoting activity of the planar 0-1 ortho ( approximately 9.7% w/w) and the nonplanar 2-4 ortho ( approximately 90.3% w/w) fraction of the commercial PCB mixture Aroclor 1260 was studied using a medium-term two-stage initiation/promotion bioassay in female Sprague-Dawley rats. Fractionation was carried out on an activated charcoal column. The composition of the effluent from the column was tested by GC-ECD. The absence of planar compounds in the 2-4 ortho fraction was confirmed by GC-MS analysis. The dioxin-like toxic potency of the fractions was determined with the DR-CALUX assay. The animal experiment was started with the initiation procedure (diethylnitrosamine injection, 30 mg/kg body wt ip, 24 h after (2)/(3) hepatectomy), followed 6 weeks later by the promotion treatment, which consisted of a weekly subcutaneous injection during 20 weeks. Exposure groups (n = 10) received the following treatments (dose/kg body wt/week): Aroclor 1260 (10 mg), 0-1 ortho fraction (0.97 mg), 2-4 ortho fraction (1, 3, or 9 mg), a reconstituted 0-4 ortho fraction (9.97 mg), 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153; 1 or 9 mg), 2,3,7,8-TCDD (1 microg; positive control) or corn oil (1 ml; vehicle control). One group did not receive a promotion treatment. All exposure groups exhibited a significantly increased volume fraction of the liver occupied by hepatic foci positive for the placental form of glutathione-S-transferase-p compared to the corn oil control, except for the groups treated with 0-1 ortho fraction and 1 mg PCB 153/kg body wt/week. Approximately 80% of the total tumor promoting capacity of the reconstituted 0-4 ortho fraction could be explained by the 2-4 ortho PCB fraction while the 0-1 ortho fraction had only a negligible contribution. These results suggest that the majority of the tumor promotion potential of PCB mixtures resides in the non-dioxin-like fraction, which is not taken into account in the toxic equivalency factor (TEF) approach for risk assessment of PCBs. This may result in an underestimation of the tumor promotion potential of environmental PCB mixtures.

Influence of the consumption of fatty Baltic Sea fish on plasma levels of halogenated environmental contaminants in Latvian and Swedish men

We examined the influence of widely varied consumption of fatty fish from the Baltic Sea and of age on plasma concentrations of polychlorinated biphenyls (PCBs), polychlorobiphenylols (OH-PCBs), 2, 2-bis(4-chlorophenyl)-1,1,1-trichloroethane (4,4'-DDT), 2, 2-bis(4-chlorophenyl)-1,1-dichloroethane (4,4'-DDE), 2,2',4, 4'-tetrabromodiphenyl ether (BDE-47), hexachlorobenzene (HCB), and pentachlorophenol (PCP) in Latvian and Swedish men. Both age and fish consumption were significantly correlated with the concentrations of [sigman]PCB, [sigman]OH-PCB, 4,4'-DDE, 4,4'-DDT, and HCB. In the case of BDE-47, no significant relationship with age was observed, and fish consumption had the largest relative effect on plasma concentrations of this contaminant. This relationship may be a result of exposure to BDE-47 having been more recent than that of PCBs and DDE, or because the half-life of BDE-47 may be shorter than that of PCB and DDE. Latvian men demonstrated higher plasma levels of DDE and DDT but lower levels of [sigman]PCB and PCP than did Swedish men. The corresponding levels of HCB and BDE-47 were similar in both countries. The Spearman's rank correlation coefficient obtained by comparing the level of the metabolite 4-hydroxy-2,3,3',4',5-pentachlorobiphenyl (4-OH-CB107) to the combined levels of its parent compounds, 2,3,3',4, 4'-pentachlorobiphenyl (CB-105) and 2,3',4,4',5-pentachlorobiphenyl (CB-118), was higher than the median correlation coefficient obtained upon comparing the level of this metabolite to all other possible combinations of two PCB levels. No other increased correlation between metabolite and parent PCB concentration was observed.

Influence of the consumption of fatty Baltic Sea fish on plasma levels of halogenated environmental contaminants in Latvian and Swedish men

We examined the influence of widely varied consumption of fatty fish from the Baltic Sea and of age on plasma concentrations of polychlorinated biphenyls (PCBs), polychlorobiphenylols (OH-PCBs), 2, 2-bis(4-chlorophenyl)-1,1,1-trichloroethane (4,4'-DDT), 2, 2-bis(4-chlorophenyl)-1,1-dichloroethane (4,4'-DDE), 2,2',4, 4'-tetrabromodiphenyl ether (BDE-47), hexachlorobenzene (HCB), and pentachlorophenol (PCP) in Latvian and Swedish men. Both age and fish consumption were significantly correlated with the concentrations of [sigman]PCB, [sigman]OH-PCB, 4,4'-DDE, 4,4'-DDT, and HCB. In the case of BDE-47, no significant relationship with age was observed, and fish consumption had the largest relative effect on plasma concentrations of this contaminant. This relationship may be a result of exposure to BDE-47 having been more recent than that of PCBs and DDE, or because the half-life of BDE-47 may be shorter than that of PCB and DDE. Latvian men demonstrated higher plasma levels of DDE and DDT but lower levels of [sigman]PCB and PCP than did Swedish men. The corresponding levels of HCB and BDE-47 were similar in both countries. The Spearman's rank correlation coefficient obtained by comparing the level of the metabolite 4-hydroxy-2,3,3',4',5-pentachlorobiphenyl (4-OH-CB107) to the combined levels of its parent compounds, 2,3,3',4, 4'-pentachlorobiphenyl (CB-105) and 2,3',4,4',5-pentachlorobiphenyl (CB-118), was higher than the median correlation coefficient obtained upon comparing the level of this metabolite to all other possible combinations of two PCB levels. No other increased correlation between metabolite and parent PCB concentration was observed.

Influence of pre-examination starvation on liver uptake of the hepatocyte-specific contrast medium FP 736-04 at CT. An experimental study in the rat

PURPOSE

To investigate the effect of starvation on contrast-enhanced CT of the liver using the iodinated hepatocyte-specific lipid emulsion FP 736-04.

MATERIAL AND METHODS

CT examination of the liver was performed in Sprague-Dawley rats before and after an i.v. infusion of 1.0 ml/kg b.w. of FP 736-04. The examination was preceded by a 15-h period of food withdrawal (the starvation group). A control group was subjected to the same CT examination protocol with use of FP 736-04 but without prior starvation.

RESULTS

Liver attenuation values did not differ significantly between the starvation and the control group (p>0.05).

CONCLUSION

A pre-examination period of starvation had no effect on FP 736-04 liver enhancement on CT However, liver attenuation tended to decrease more slowly in the starvation group than in the controls.

Target cells for methylsulphonyl-2,6-dichlorobenzene in the olfactory mucosa in mice

Previously we reported that methylsulphonyl-2,6-dichlorobenzene, 2, 6-(diCl-MeSO(2)-B), was irreversibly bound to the olfactory mucosa of mice and induced necrosis of the Bowman's glands with subsequent neuroepithelial degeneration and detachment. In this study, autoradiography and histopathology were used to determine tissue-localization and toxicity of 2,6-(diCl-MeSO(2)-B) in the olfactory mucosa of control mice and animals pretreated with cytochrome P450 (CYP) and glutathione (GSH) modulators. The Bowman's glands of the olfactory mucosa were the major target sites of non-extractable binding of 2,6-(diCl-(14)C-MeSO(2)-B), whereas the olfactory neuroepithelium and nerve bundles showed only background levels of silver grains. Metyrapone pretreatment slightly decreased binding in the Bowman's glands and markedly decreased toxicity in the olfactory mucosa after 2,6-(diCl-MeSO(2)-B) administration. These results support that a CYP-mediated activation of 2, 6-(diCl-MeSO(2)-B) takes place in the Bowman's glands giving rise to toxic reactive intermediates. In mice pretreated with the GSH-depleting agent phorone, a marked increase of irreversible binding of 2,6-(diCl-(14)C-MeSO(2)-B) in the Bowman's glands was observed. Tape-section autoradiograms also revealed a significant increase of uptake of radioactivity in the olfactory bulb. As determined by histopathology, GSH-depletion increased both the extent and severity of the lesion in the mucosa. These results imply that 2,6-(diCl-MeSO(2)-B)-reactive intermediates are conjugated with GSH. The amount of irreversible binding and toxicity in the olfactory mucosa seems to be associated with the level of 2, 6-(diCl-MeSO(2)-B)-reactive intermediates.

Inv dup(22), del(22)(q11) and r(22) in the father of a child with DiGeorge syndrome

We here report a unique inherited case of DiGeorge syndrome. The asymptomatic father had a mosaic karyotype with a 21q11 deletion in three different cell lines. In two of the cell lines there was an additional supernumerary inv dup(22) or an r(22), respectively. In the third cell line the del(22) was the sole anomaly. FISH analysis showed that both the inv dup(22) and the r(22) included the DGS region. We hypothesize that an inter-chromosomal recombination between inverted repeats, together with a recombination between sister chromatids during meiosis I, gave rise to a deletion of 22q11 as well as an inv dup(22) containing the DGS region. The inv dup(22) was later rearranged into a ring chromosome during mitosis which was subsequently lost during cell division, thereby resulting in three different cell lines. This is the first case reported with an inv dup(22) and a del(22)(q11) in the same cell line. Our findings support a related mechanism in the formation of these two rearrangements mediated by low-copy repeats.

Structure of human transthyretin complexed with bromophenols: a new mode of binding

The binding of two organohalogen substances, pentabromophenol (PBP) and 2,4,6-tribromophenol (TBP), to human transthyretin (TTR), a thyroid hormone transport protein, has been studied by in vitro competitive binding assays and by X-ray crystallography. Both compounds bind to TTR with high affinity, in competition with the natural ligand thyroxine (T(4)). The crystal structures of the TTR-PBP and TTR-TBP complexes show some unusual binding patterns for the ligands. They bind exclusively in the 'reversed' mode, with their hydroxyl group pointing towards the mouth of the binding channel and in planes approximately perpendicular to that adopted by the T(4) phenolic ring in a TTR-T(4) complex, a feature not observed before. The hydroxyl group in the ligands, which was previously thought to be a key ingredient for a strong binding to TTR, does not seem to play an important role in the binding of these compounds to TTR. In the TTR-PBP complex, it is primarily the halogens which interact with the TTR molecule and therefore must account for the strong affinity of binding. The interactions with the halogens are smaller in number in TTR-TBP and there is a decrease in affinity, even though the interaction with the hydroxyl group is stronger than that in the TTR-PBP complex.

Metabolism, excretion and distribution of the flame retardant tetrabromobisphenol-A in conventional and bile-duct cannulated rats

1. 14C-TBBP-A (2,2-bis(4-hydroxy-3,5-dibromophenyl)propane) was administered orally to the conventional and bile-duct cannulated male Sprague-Dawley rat (2.0 mg/kg body weight). Urine, bile and faeces were collected daily for 72 h, and selected tissues were removed for distribution studies. 2. Faeces was the major route of elimination of TBBP-A in the conventional rat (91.7% of dose), and urine was a minor elimination route (0.3%). Enterohepatic circulation was suggested by biliary excretion of 71.3% and faecal excretion of 26.7% of the administered radioactivity in the bile-duct cannulated rat. 3. 14C-labelled residues in tissues were 2% in the conventional rat, and < 1% in the bile-duct cannulated rat. The large and small intestines contained the majority of the tissue 14C activity for both groups of rat. Levels of TBBP-A in liver were < 0.1% and in fat were below the level of quantification. 4. Three metabolites were characterized in 0-24 h bile samples. Glucuronic acid and sulphate ester conjugates were characterized by mass spectrometry. More than 95% of the extractable faecal 14C was identified as parent TBBP-A. 5. Negligible amounts of TBBP-A-derived 14C were associated with carrier proteins in the urine and bile.

Detection and characterisation of renal lesions by multiphasic helical CT

PURPOSE

The fast helical CT technique allows examination of the kidneys during different phases of contrast medium enhancement. However, every additional phase increases the radiation dosage to the patients. We investigated the detection rate and characterisation of renal lesions during different phases and evaluated them separately, and considered the possibility of excluding phases without loss of important information.

MATERIAL AND METHODS

Sixty patients who underwent contrast-enhanced multiphasic renal helical CT examination were included. Every CT phase was evaluated separately. The number of lesions and the characteristics of the lesions were noted and all lesions were viewed together.

RESULTS

A total of 153 cysts and 17 solid lesions were detected. The largest and an equal number of cysts (142/143) was detected in the nephrographic and excretory phases. However, the nephrographic phase detected more cortical cysts and the excretory phase detected more sinus cysts. All solid lesions were detected in all phases. Renal parenchymal tumours were best characterised in the cortical phase and angiomyolipomas in the native phase.

CONCLUSION

The cortical phase was best for characterisation of renal parenchymal tumours. The nephrographic and excretory phases were best in detecting and characterising renal cysts. The nephrographic phase was the phase giving the least diagnostic information.

Potent competitive interactions of some brominated flame retardants and related compounds with human transthyretin in vitro

Brominated flame retardants such as polybrominated diphenyl ethers (PBDEs), pentabromophenol (PBP), and tetrabromobisphenol A (TBBPA) are produced in large quantities for use in electronic equipment, plastics, and building materials. Because these compounds have some structural resemblance to the thyroid hormone thyroxine (T(4)), it was suggested that they may interfere with thyroid hormone metabolism and transport, e.g., by competition with T(4) on transthyretin (TTR). In the present study, we investigated the possible interaction of several brominated flame retardants with T(4) binding to TTR in an in vitro competitive binding assay, using human TTR and 125 I-T(4) as the displaceable radioligand. Compounds were tested in at least eight different concentrations ranging from 1.95 to 500 nM. In addition, we investigated the structural requirements of these and related ligands for competitive binding to TTR. We were able to show very potent competition binding for TBBPA and PBP (10.6- and 7.1-fold stronger than the natural ligand T(4), respectively). PBDEs were able to compete with T(4)-TTR binding only after metabolic conversion by induced rat liver microsomes, suggesting an important role for hydroxylation. Brominated bisphenols with a high degree of bromination appeared to be more efficient competitors, whereas chlorinated bisphenols were less potent compared to their brominated analogues. These results indicate that brominated flame retardants, especially the brominated phenols and tetrabromobisphenol A, are very potent competitors for T(4) binding to human transthyretin in vitro and may have effects on thyroid hormone homeostasis in vivo comparable to the thyroid-disrupting effects of PCBs.

Potent inhibition of estrogen sulfotransferase by hydroxylated PCB metabolites: a novel pathway explaining the estrogenic activity of PCBs

Polychlorinated biphenyls (PCBs) are persistent environmental pollutants which exert a variety of toxic effects in animals, including disturbances of sexual development and reproductive function. The estrogenic effects of PCBs may be mediated in part by hydroxylated PCB metabolites (PCB-OHs), but the mechanisms by which they are brought about are not understood. PCBs as well as PCB-Hs show low affinities for both alpha and beta estrogen receptor isoforms. In the present study we demonstrate that various environmentally relevant PCB-OHs are extremely potent inhibitors of human estrogen sulfotransferase, strongly suggesting that they indirectly induce estrogenic activity by increasing estradiol bioavailability in target tissues.

Biochemical and genetic interactions between Drosophila caspases and the proapoptotic genes rpr, hid, and grim

In Drosophila melanogaster, the induction of apoptosis requires three closely linked genes, reaper (rpr), head involution defective (hid), and grim. The products of these genes induce apoptosis by activating a caspase pathway. Two very similar Drosophila caspases, DCP-1 and drICE, have been previously identified. We now show that DCP-1 has a substrate specificity that is remarkably similar to those of human caspase 3 and Caenorhabditis elegans CED-3, suggesting that DCP-1 is a death effector caspase. drICE and DCP-1 have similar yet different enzymatic specificities. Although expression of either in cultured cells induces apoptosis, neither protein was able to induce DNA fragmentation in Drosophila SL2 cells. Ectopic expression of a truncated form of dcp-1 (DeltaN-dcp-1) in the developing Drosophila retina under an eye-specific promoter resulted in a small and rough eye phenotype, whereas expression of the full-length dcp-1 (fl-dcp-1) had little effect. On the other hand, expression of either full-length drICE (fl-drICE) or truncated drICE (DeltaN-drICE) in the retina showed no obvious eye phenotype. Although active DCP-1 protein cleaves full-length DCP-1 and full-length drICE in vitro, GMR-DeltaN-dcp-1 did not enhance the eye phenotype of GMR-fl-dcp-1 or GMR-fl-drICE flies. Significantly, GMR-rpr and GMR-grim, but not GMR-hid, dramatically enhanced the eye phenotype of GMR-fl-dcp-1 flies. These results indicate that Reaper and Grim, but not HID, can activate DCP-1 in vivo.

Learning and memory impairment in cocaine-dependent and comorbid schizophrenic patients

Impairments in verbal learning and memory functioning have been found to be cardinal features among individuals with schizophrenia as well as among non-schizophrenic cocaine abusers. Cognitive deficits in these areas, moreover, have been associated with poor treatment response and short-term outcome. Little is known, however, about the acute effects of cocaine abuse on schizophrenic patients' learning and memory functioning. Consequently, a potentially reversible and treatable source of cognitive impairment has been virtually ignored. The present study examined the extent of verbal learning and memory impairment in a group of cocaine-dependent schizophrenic patients (n=42) and a group of non-schizophrenic cocaine-dependent patients (n=21) within 72 h of the last cocaine use using the California Verbal Learning Test (CVLT). Schizophrenic patients (n=34) without any substance-use disorders were also tested in an identical time frame and served as a comparison group. Results revealed that all groups demonstrated significant learning and memory impairment relative to CVLT published age and gender corrected norms. Both cocaine-dependent and non-substance abusing schizophrenic groups presented a very similar pattern of impaired learning and recall performance across all CVLT task domains. Comorbid patients, in contrast, presented with marked deficits in their ability to learn and recall verbal information relative to either schizophrenic or cocaine-only groups. Moreover, the cocaine-abusing schizophrenic patients showed significant forgetfulness of the information that they did acquire during delayed recall conditions. The performance deficits exhibited by cocaine-abusing schizophrenic patients differed not only in relative severity of impairment, but also qualitatively in their increased rates of forgetfulness of acquired information. These results are interpreted in terms of the neurobiological substrates of learning and memory and the neurobiological impact of cocaine on schizophrenic patients' cognition during the early phase of inpatient hospitalization. These results suggest that comorbid patients should be targeted for specialized remediation efforts at the beginning phases of inpatient treatment.

Napsin A, a member of the aspartic protease family, is abundantly expressed in normal lung and kidney tissue and is expressed in lung adenocarcinomas

A pair of 35 kDa polypeptides (TAO1/TAO2) are expressed in more than 90% of all primary lung adenocarcinomas but not in other major malignancies. Mass spectrometry of tryptic peptides showed that TAO1/TAO2 is identical to napsin A, a recently described member of the aspartic proteinase family. The site of processing of pronapsin A to the mature form was located. Napsin expression was detected in human lung adenocarcinoma tumors, compatible with the marker nature of TAO1/TAO2 in the diagnosis of primary lung adenocarcinoma. This is important since identification of markers which can distinguish primary lung adenocarcinomas from distant metastases is desirable. Northern blot analysis showed expression of napsin also in normal lung and kidney tissue, and in situ hybridization showed expression in type II alveolar cells of the lung. This protease is concluded to have a specific functional role in the normal alveolar epithelium and is a candidate protease for the proteolytic processing of surfactant precursors.

Analysis of polybrominated diphenyl ethers in Swedish human milk. A time-related trend study, 1972-1997

A previously described method for analysis of organochlorine compounds in human milk was adopted for analysis of brominated diphenyl ethers (BDEs) substituted with three to six bromine atoms. Analytes were extracted from human milk with the lipophilic gel Lipidex 5000. Further purifications were performed on partly deactivated aluminum oxide and silica gel columns, followed by gel permeation chromatography. The concentrations of BDEs were determined by gas chromatography/mass spectrometry (GC/MS). The average recoveries of 2,2',4-triBDE (BDE-17), 2,4,4'-triBDE (BDE-28), 2,2',4,4'-tetraBDE (BDE-47), 2,3',4,4'-tetraBDE (BDE-66), 2,2,3,4,4'-pentaBDE (BDE-85), 2,2',4,4',5-pentaBDE (BDE-99), 2,2',4,4',6-pentaBDE (BDE-100), 2,2',4,4',5,5'-hexaBDE (BDE-153), and 2,2',4,4',5,6'-hexaBDE (BDE-154) added to the samples before extraction ranged from 86% to 102%. Pooled samples of breast milk, collected at eight time periods between 1972 and 1997, were analyzed for PBDEs. BDE-47 was the most abundant PBDE congener in all samples. In total, eight PBDE congeners were identified in the milk. The sum of the concentrations of BDE congeners in human milk increased from 0.07 to 4.02 ng/g lipids during the 25-yr period studied.

Halogenated environmental contaminants in perch (Perca fluviatilis) from Latvian coastal areas

The environmental contamination situation in coastal areas of the former Soviet Union has up to now been more or less unknown. This study on perch (Perca fluviatilis), collected at three locations along the coast of Latvia during 1994 and 1995, provides concentrations of several ubiquitous environmental contaminants (PCBs, HCB, HCHs, 4,4'-DDT, 4,4'-DDE, 4,4'-DDD, trans-Nonachlor, 2,2',4,4'-tetrabromodiphenyl ether). The concentrations of total PCB were similar at all study locations [0.7-1.4 ppm on a lipid weight (l.w.) basis], although a site close to the City of Riga indicated the presence of a local PCB contamination source. The contamination source was identified mainly by a higher relative content of lower chlorinated PCB congeners in the samples. Local pollution sources were also indicated for HCH and DDT. A large variation in the HCH isomer composition between 1994 and 1995 at one location demonstrates short half-lives of HCHs in the environment. The brominated flame retardant compound 2,2',4,4'-tetrabromdiphenyl ether was present in the range of 6.4-10 ng/g l.w. in the perch. The clean-up method applied in this study allowed for quantification of two semi-polar contaminants frequently overlooked in Baltic biota, namely Dieldrin and bis(4-chlorophenyl) sulfone (BCPS). Concentrations of BCPS were remarkably high, i.e. in the same magnitude as the most abundant PCB congeners. The results presented shows that the contamination of, e.g. PCB in an area of the former Soviet Union, the Gulf of Riga, is similar to that observed in other parts of the Baltic area.

Cytotoxicity and aromatase (CYP19) activity modulation by organochlorines in human placental JEG-3 and JAR choriocarcinoma cells

The human placental JEG-3 and JAR choriocarcinoma cell lines have been used as placental models for the study of aromatase (CYP19) activity and endocrine functions. In the present study, 21 organochlorines (OCs) mediated decreases in aromatase activity and protein and DNA content and increases in the percent lactate dehydrogenase (LDH) leakage in JEG-3 cells. These effects were highly variable among the types of OC and their treatment concentrations. Lowest observed effective concentrations reached 0. 001 microM for several OCs. Aromatase activity decreases and OC-mediated cytotoxicity were related. Thus, it was not possible to clearly assess the capacity of the OCs to modulate aromatase activity. Similar to 1,4-naphthoquinone, the most cytotoxic OCs contained a hydroxyl (4'-OH-2,4,6-trichlorobiphenyl and tris(4-chlorophenyl)methanol) or methylsulfonyl- (3- and 4-MeSO(2)-2, 2',5,5'-tetrachlorobiphenyl and -2,3',4',5-tetrachlorobiphenyl, and 3'- and 4'-MeSO(2)-2,2',3,4,5'-pentachlorobiphenyl and -2,2',4,5, 5'-pentachlorobiphenyl) functional group. Modulation of aromatase activity and LDH leakage were less for 3,3',4,4', 5-pentachlorobiphenyl and benzo[a]pyrene and insignificant for five alkyl-substituted trichloro-dibenzofurans and 2,3,7, 8-tetrachloro-dibenzo-p-dioxin (up to 10 microM). Cytotoxicity-related effects were influenced by the cell density and the presence of 10% fetal calf serum in the medium during compound incubation. Similar cytotoxic effects were observed for the JAR cell line. The involvement of an apoptotic mechanism of cytotoxicity in OC-treated JEG-3 cells was suggested by the binding of APO2.7 (an antibody specific to apoptotic cells), DNA fragmentation, and trypan blue staining. JEG-3 and JAR cells appear too sensitive toward OC-mediated cytotoxicity for use as in vitro bioassays to evaluate the potential modulation of aromatase activity. However, these cell lines may prove useful for examining the capacity of xenobiotics to modulate placental toxicity.