Occurrence of perfluorinated substances in an adult German population in southern Bavaria

Objectives Perfluorinated compounds (PFCs) are a large group of chemicals produced for several decades and widely used for many industrial and consumer applications. Because of their global occurrence in different environmental media, their persistence, and their potential to bioaccumulate in organisms they are of toxicological and public concern. Methods In the present study, the internal exposure to perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in 356 human plasma samples collected from an adult population in Germany in 2005 is quantified. Results We were able to detect the target analytes in all plasma samples and observed a significant correlation between the PFOS and PFOA concentrations. In female participants, the levels of PFOS and PFOA ranged between 2.5–30.7 (median: 10.9 μg/l) and 1.5–16.2 μg/l (median: 4.8 μg/l), respectively. In males we observed concentrations from 2.1 to 55.0 μg/l (median: 13.7 μg/l) for PFOS and from 0.5 to 19.1 μg/l (median: 5.7 μg/l) for PFOA. A significant correlation between both PFOS and PFOA concentrations and gender was observed. We also found increased levels of the PFCs with increasing age of the participants, but this association reached statistical significance among females only. Conclusions Our data agree well with results of other recent studies in Europe and suggest that the current exposure of the adult German population is lower than the exposure of the US and Canadian population. The sources of human exposure are currently not well understood. Toxicological implications are restricted to animal studies and occupational investigations not adequate for quantitative risk assessment in humans. Overall, more scientific research is necessary to characterize the body burden of PFCs (especially for relevant subsets of the population) and the main sources and routes, which are responsible for human exposure and possible health implications of these compounds.     

Corrosion Performance of Nano-TiO2-Modified Concrete under a Dry–Wet Sulfate Environment

This study compared the effects of the sulfate dry–wet cycle on the properties of ordinary concrete and nano-TiO₂-modified concrete, including the mass loss rate, ultrasonic wave velocity, compressive strength, and XRD characteristics. In addition, a series of compression simulations carried out using the PFC2D software are also presented for comparison. The results show the following: (1) with an increase in dry–wet cycles, the damage to the concrete gradually increased, and adding nano-TiO₂ into ordinary concrete can improve the material’s sulfate resistance; (2) after 50 sulfate dry–wet cycles, the mass loss rate of ordinary concrete was –3.744%, while that of nano-TiO₂-modified concrete was −1.363%; (3) the compressive strength of ordinary concrete was reduced from 41.53 to 25.12 MPa (a reduction of 39.51%), but the compressive strength of nano-TiO₂-modified concrete was reduced from 49.91 to 32.12 MPa (a reduction of 35.64%); (4) after a sulfate dry–wet cycle, the nano-TiO₂-modified concrete surface produced white crystalline products, considered to be ettringite based on the XRD analysis; (5) when considering the peak stress and strain of the concrete samples, the numerical results agreed well with the test results, indicating the reliability of the method.     

Micro-Mechanism of Uniaxial Compression Damage of Layered Cemented Backfill in Underground Mine

Layering of filling body is common in large-scale filling areas. In this paper, the cement–sand ratio of 1:8 is based on the configuration of 68%, 70%, 72% and 74%; four concentrations; and filling layers of one-, two-, three- and four-layered cemented filling samples. Combined with a uniaxial compression test and two-dimensional particle flow software (PFC2D), the mechanical properties and failure modes were explored. The results show that the concentration can strengthen the uniaxial compressive strength of the filling body while increasing the filling times weakens its power; therefore, the constitutive damage model was constructed. It was found that the initial layered damage existed in the layered filling, and the total damage showed an upward trend of first fast and then slow; the main failure modes of one-layer and two-layer backfills showed prominent shear failure characteristics, and the three-layer and four-layer fillings were closer to tensile failure. From the crack generation to the specimen failure, there is a mutual conversion between different energies.     

Nonsuppression of cortisol in depression and immune function

Eighteen depressive patients and twenty-five healthy control subjects were studied using a comprehensive immunological test system and the dexamethasone suppression test (DST) as well as some additional neuroendocrine parameters. In addition, immune functions of six of the patients were studied serially three times at 1-2 month's intervals. The OKT 4+/8+ ratio (OKT 4+ = helper/inducer phenotype; OKT 8+ = suppressor/cytotoxic phenotype) was slightly higher in those ten depressive patients showing suppression in the DST than in healthy controls, but there were no significant differences between the nonsuppressor and suppressor groups or between the nonsuppressor and suppressor groups or between nonsuppressors and control subjects. Lymphocyte transformation responses induced by phytohaemagglutinin (PHA) were similar in the nonsuppressors and suppressors, but lower in both groups than in control subjects. The number of Ig-secreting cells measured in the absence and presence of pokeweed mitogen (PWM) were similar in the nonsuppressor and suppressor groups. Four of the depressive patients tested repeatedly exhibited an abnormal response in the DST at the beginning of the study. During the follow-up period two of them recovered completely from depression as well as the patients with a normal suppression in the DST. The proportions of T and B lymphocytes and regulatory T lymphocyte subsets as well as the functions of T and B lymphocytes of the nonsuppressors and suppressors in the DST were within normal ranges before and after recovery from depression and comparable to healthy controls in repeated testing. The results indicate that in spite of the importance of cortisol in immunoregulation, the increased cortisol secretion and typical resistance to dexamethasone suppression in endogenously depressive patients is not profoundly and consistently reflected in immune functions. Neither does normalization of cortisol responses induce any major changes in immune status during a patient's recovery from depression. Previous work indicates that suppressed immunity may play an important role in the increased morbidity and mortality associated with bereavement. In the light of present findings we suggest that endogenous depression differs also in this respect from grief reactions.     

恶性疟原虫PFC0460w基因片段的克隆与生物信息学分析

用逆转录PCR方法从恶性疟原虫3D7株红内期RNA扩增PFCO460w基因片段,克隆于pGEM-T easy载体,转化大肠埃希菌DH5α,筛选阳性克隆,PCR鉴定、测序并作序列分析。结果显示,从恶性疟原虫3D7株中扩增到3种PFCO460w片段序列,分别为618、597和543 bp,其中618 bp的片段序列与PlasmoDB数据库中的已知序列完全一致（GenBank登录号为XM₀01351147）。597 bp和543 bp片段序列已登录GenBank数据库,登录号分别为JF799872和JF799873。618 bp片段编码205个氨基酸,经Robbeta服务器结构预测,其编码的蛋白质可能有5种三维结构。     

Purification and characterization of a mouse T cell replacing factor from primary mixed lymphocyte culture supernatant

The purification and chemical characterization of a T cell replacing factor (TRF), which was induced in the supernatant of primary mixed lymphocyte cultures for 24 hr under serum-free conditions, has been carried out. This TRF was sensitive to proteolytic enzymes, trinitrobenzene sulfonic acid and sodium metaperiodate, while it was stable in buffers of a wide pH range (pH 5–10) and to freezing and thawing treatment. After purification of the TRF by DEAE Sephadex A-50 ion-exchange chromatography, preparative disc electrophoresis and gel filtration on Sephadex G-100, the final product revealed only one band after sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Chemical analyses of the purified TRF showed that it was a protein, abundant in serine, valine, glycine, glutamic acid, almost devoid of basic amino acids and that it contained approximately 10% carbohydrate. Furthermore, the purified TRF described in this paper was found to consist of two identical subunits of molecular weight of 21,000 ± 3000 daltons.     

Effect of adolescent exposure to WIN 55212-2 on the acquisition and reinstatement of MDMA-induced conditioned place preference

The present study employs a conditioned place preference procedure (CPP) to examine the effects of exposure to the cannabinoid agonist WIN 55212-2 (WIN) (0.1 and 0.5 mg/kg) during adolescence on the reinforcing properties of ± 3,4-methylenedioxymetamphetamine hydrochloride (MDMA) (1.25 and 2.5 mg/kg) in mice. On postnatal day (PD) 27, animals received a daily injection of the assigned treatment on 5 consecutive days, and three days later the place conditioning procedure was initiated (PD 35). The results suggest that pre-exposure to cannabinoids strengthens the properties of MDMA and favors reinstatement of the craving for the drug, which endorses the gateway hypothesis.     

Antidepressant-like effect of the methanolic extract from Bupleurum falcatum in the tail suspension test

In traditional Oriental medicine, some herbal combinations that include Bupleurum falcatum (BFM) as a major ingredient are known to effectively treat depressive-like disorders. In the present study, the antidepressant-like effect of methanolic extract of BFM and its neuropharmacological mechanism were investigated in mice. After oral administration of BFM extract, a tail suspension test (TST) and open field test (OFT) were performed to assess the antidepressant activity and psycho-stimulant side-effects, respectively. Pre-treatment with p-chlorophenylalanine (PCPA, a serotonin synthesis inhibitor) and α-methyl-p-tyrosine (AMPT, a catecholamine synthesis inhibitor) was used to assess the influence of BFM extract on the antidepressant activity in the TST. At doses of 150 and 300 mg/kg body weight, p.o., the BFM extract significantly reduced the total duration of immobility in the TST, while individual differences in locomotor activities between experimental groups were not observed in the OFT. Moreover, pre-treatment with PCPA (100 mg/kg i.p., for 4 consecutive days) or AMPT (100 mg/kg i.p.) significantly inhibited the antidepressant-like activity of BFM extract (300 mg/kg p.o.), as well as we confirmed the reversal of the antidepressant effect of fluoxetine (30 mg/kg i.p.) by PCPA and bupropion (20 mg/kg i.p.) by AMPT in the TST. Taken together, these findings suggest that the methanolic BFM extract has dose-dependent possibility of antidepressant-like activity valuable to alternative therapy for depression and that the mechanism of action involves the serotonergic and noradrenergic systems although underlying mechanism still remains to be further elucidated.     

Fetal asphyxia leads to the loss of striatal presynaptic boutons in adult rats

Fetal asphyxic insults in the brain are known to be associated with developmental and neurological problems like neuromotor disorders and cognitive deficits. Little is known, however, about the long-term consequences of fetal asphyxia contributing to the development of different neurological diseases common in the adult or the aging brain. For that reason the present study aimed to investigate the long-term effects of fetal asphyxia on synaptic organization within the adult rat brain. Fetal asphyxia was induced at embryonic day 17 by 75-min clamping of the uterine and ovarian arteries. Presynaptic bouton densities and numbers were analyzed in the striatum and prefrontal cortex at the age of 19 months. A substantial decrease in presynaptic bouton density and number was observed in the striatum of fetal asphyxia rats compared to control rats, while an increase was found in the fifth layer of the prefrontal cortex. These results suggest that fetal asphyxia can have long-lasting effects on synaptic organization that might contribute to a developmental etiology of different neurological disorders and aging.