Exposure to dioxin-like pollutants via different food commodities in Swedish children and young adults

The dietary intake of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs) in terms of toxic equivalents (TEQs) was investigated in Swedish children and young adults. Exposure was estimated from concentration data of six groups of individual food commodities (meat, fish, dairy products, egg, edible fats and other foodstuff) combined with food intake data from a 7-day record book obtained from 670 individuals aged 1–24 years. The results showed that Swedish boys and girls, up to the age of ten, had a median TEQ intake that exceeded the tolerable daily intake (TDI) of 2 pg TEQ/kg body weight. Children exceeding the TDI varied from almost all individuals among the youngest children to about 20% among young men and women. Dairy and fish products were the main sources of exposure for the average child, accounting for 59% of the total TEQ intake. The individuals most highly exposed were, on the other hand, characterized by a high consumption of fish. Since children constitute a vulnerable group, results obtained from the present study show that it is essential to perform age specific dietary intake assessments of pollutants and more carefully consider sensitive and/or highly exposed groups in the population in the risk management processes.     

Further comparative studies on chemical properties of carcinoembryonic antigen in tumor tissues and closely related antigens in adult feces and meconium

The chemical structure of carcinoembryonic antigen (CEA) and two closely related antigens, normal fecal antigen-2 (NFA-2) in normal adult feces and nonspecific cross-reacting antigen-2 (NCA-2) in the meconium, were further analyzed comparatively. The NH2-terminal amino acid sequence of NCA-2 was newly determined to position 18 and found to be identical to that so far determined for CEA- and NFA-2. After proteolytic digestion with chymotrypsin or protease V8, the digests of these antigens showed two groups of fragments upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. One consisted of the sharply banded fragments which were identical in all antigens and stained only with Coomassie brilliant blue (CBB) (five bands in the range 2500-10,000 daltons for chymotrypsin and 11 bands in the range 8000-35,000 daltons for protease V8, respectively), and the other consisted of the dispersed fragments which had variable mol. wts in the range 10,000-100,000 and were stainable with both CBB and periodic acid-Schiff reagent. Elution profiles of CEA, NFA-2, and NCA-2 from lectin columns, especially from concanavalin A-Sepharose columns, suggested some differences in oligosaccharide chains between them. These results indicate that the fundamental chemical structure of these antigens seems to be very similar to one another and is divided into two parts; an homologous portion(s) which is common to all three antigens and contains no sialylated sugar components, and a heterogeneous portion(s) which is variable among these antigens and contains sialylated sugar components.     

尼氟灭酸对氯化钴诱导血管内皮细胞凋亡的保护作用

目的：探讨尼氟灭酸（NFA）对氯化钴（CoCl2）诱导血管内皮细胞凋亡的保护作用,阐明其可能的机制。方法将血管内皮细胞随机分为对照组、100μmol／L CoCl2损伤组和20、40μmol／L NFA保护组,四甲基偶氮唑蓝比色（ MTT）法检测各组细胞增殖活性,酶联免疫吸附试验（ ELISA ）检测细胞内相关凋亡蛋白Bcl-2、Bax及Caspse-3的表达情况。结果 MTT检测,与对照组比较,100μmol／L CoCl2组在24 h细胞增殖活性明显降低（P＜0．01）;与CoCl2损伤组相比,20、40μmol／L NFA保护组在24 h细胞增殖活性升高（P＜0．05,P＜0．01）,40μmol／L NFA保护组更加明显。 ELISA法检测显示,与对照组比较,100μmol／L CoCl2组在24 h细胞Caspse-3、Bax的表达增多,Bcl-2表达减少（ P＜0．05,P＜0．01）。与损伤组相比,NFA处理缺氧后血管内皮细胞Caspse-3、Bax的表达减少,Bcl-2表达增多（P＜0．05,P＜0．01）。结论 CoCl2能诱导血管内皮细胞缺氧损伤,引起细胞的凋亡;NFA可以保护CoCl 2诱导的血管内皮细胞的缺氧损伤,这可能与上调Bcl-2、下调Bax和Caspse-3抑制其凋亡有关。     

Incorporation of labelled galactose into glycoconjugates by bulk isolated rat brain astroglial and neuronal cells in vitro

Neuronal and astroglial cells isolated from 5-day-old rat brains were found to incorporate [³H]galactose into glycosphingolipids and glycoproteins. Glycosphingolipid labelling was higher in astroglial cells but glycoprotein labelling was similar in both cell types. Galactose incorporation into glucocerebrosides was higher compared to galactocerebrosides. Labelled galactose can also be incorporated into gangliosides and other minor glycosphingolipids by both neuronal and astroglial cells.     

尼氟酸抑制慢性内脏痛大鼠海马CA1区突触长时程增强

目的:探讨尼氟酸(HCN2特异性阻断剂)对慢性内脏痛大鼠海马CA1(cornu ammonis 1)区突触长时程增强(LTP)的影响。方法:选用新生SD大鼠(雌雄不分)出生后8～14 d内,每天固定时间给予1次60 mmHg压力的结直肠扩张刺激建立慢性内脏痛模型,大鼠成年后通过测量腹外斜肌对结直肠扩张引起的放电反应来评估肠道痛觉的敏感性。采用离体脑片场电位的记录方法,观察慢性内脏痛大鼠海马CA1区场电位LTP的变化,并观察不同浓度(25～75 mg/L)的尼氟酸对慢性内脏痛大鼠海马CA1区场电位LTP的影响。结果:慢性内脏痛大鼠海马基础场电位的幅值及斜率与正常大鼠比较无显著性差异,但高频刺激后模型大鼠诱导出的LTP幅值及斜率的变化率与正常大鼠比较均显著增加(P<0.05);尼氟酸对正常大鼠离体海马场电位LTP的峰值和斜率没有任何影响,但是不同剂量(25～75 mg/L)的尼氟酸可剂量依赖性显著降低慢性内脏痛大鼠离体海马场电位LTP的峰值及斜率。结论:HCN2通道可能参与慢性内脏痛大鼠海马场电位LTP的易化过程。     

Quantification of retinal nerve fiber thickness. A comparison of laser scanning ophthalmoscopy, polarimetry and optical coherence tomography in healthy and glaucomatous eyes

Purpose. To evaluate the thickness of the retinal nerve fiber layer (RNFL) in healthy eyes and in eyes of patients with primary open angle glaucoma using the Heidelberg retina tomograph (HRT), the nerve fibre analyser (NFA) and the optical coherence tomograph (OCT). Methods. In this prospective cohort study, 40 normal eyes and 86 eyes of age-matched glaucoma patients were compared by confocal scanning laser tomography using the HRT, scanning laser polarimetry (NFA) and optical coherence tomography (OCT). The RNFL thickness was measured in the superior, inferior, nasal and temporal regions as well as the total circumference. Results. All three methods revealed a statistically significant difference between normal and glaucomatous eyes with respect to the mean RNFL thickness in the inferior and superior regions (p<0.001). The mean RNFL thickness in the superior region was 329 μm (HRT), 87 μm (NFA) and 94 μm (OCT) in healthy volunteers compared to 275 μm (HRT), 72 μm (NFA) and 82 μm (OCT) in the patient group. In the inferior region, it was 323 μm (HRT), 87 μm (NFA) and 93 μm (OCT) in healthy subjects versus 240 μm (HRT), 74 μm (NFA) and 83 μm (OCT) in glaucoma patients. Cut-off points to differentiate between normal and glaucomatous eyes could not be defined. There was no difference in the RNFL thickness of right and left eyes. Conclusions. In RNFL thickness measurements using HRT, NFA and OCT, glaucoma patients showed a significantly thinner RNFL in the superior and inferior areas compared to healthy volunteers. These results confirm the known histological and fundus photographic findings of RNFL thinning near the optic disc in glaucoma patients. Although RNFL thickness cannot be used to diagnose glaucoma in individual patients due to the high interindividual differences, the quantitative assessment of RNFL thickness may complement the diagnostic armamentarium as a sensitive parameter for diagnosing and monitoring glaucomas.     

Persistent organochlorine and organobromine compounds in mother's milk from Sweden 1996-2006: Compound-specific temporal trends

High body burdens of persistent halogenated organic pollutants (POPs) among pregnant and nursing women are of concern because of exposure of the growing foetus and breast-feeding infant. We examined the temporal trends of polychlorinated biphenyls (PCBs), dibenzo-p-dioxin (PCDDs) and dibenzofurans (PCDFs), polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD) in milk samples from Swedish women. POPs were analysed in individual mother's milk samples from randomly recruited primiparas (N=335) who lived in Uppsala County and delivered between 1996 and 2006. Results were adjusted for life-style factors that are associated with POP body burdens. PCB levels declined 3.9-8.6% per year. The levels of PCDDs decreased faster (6-9% per year) than the levels of PCDFs (3-6% per year). Temporal trends of PBDEs did not follow any consistent pattern. Concentrations of BDE-47 and BDE-99 decreased, while the concentrations of BDE-153 increased. No change in BDE-100 concentrations was observed. In most samples, concentrations of HBCD were below the quantification limit (<0.20 ng/g lipid). Generally, adjustment of the temporal trends of PCBs and PCDD/Fs for personal characteristics of the mothers (age, body mass index (BMI), weight changes during and after pregnancy) resulted in faster declining rates, with age having the greatest influence. The age of the participating mothers increased during the study period, and since the POP levels increased with increasing age, this counteracted the decreasing temporal trends in the unadjusted model. It is consequently important to include personal characteristics in the analysis of temporal trends of POPs. Compound-specific temporal trends are probably caused by differences in sources of exposure, as well as by differences in persistence between compounds.     

Reproducibility of measuring retinal nerve fiber density. Comparison of optical coherence tomography with the nerve fiber analyzer and the Heidelberg retinal tomography device

Background. Glaucoma is associated with a progressive loss of retinal ganglion cell axons and the evaluation of the thickness of the retinal nerve fibre layer (RNFL) is important for early diagnosis and follow-up. Results of RNFL thickness measurements may vary according to the devices used. Therefore, the present study has analysed and compared the reproducibility of data obtained with three different instruments. Methods. RNFL thickness was determined using a circular identification line around the optic nerve head by optical coherence tomography (OCT), a Heidelberg Retina Tomograph (HRT) and a Nerve Fiber Analyser (NFA). Each eye was tested six times. The values for RNFL thickness were calculated for the superior, inferior, nasal and temporal areas. A one-way analysis of variance with random effects was chosen to estimate the variance components. The intraclass correlation coefficient (ICC) as a measure of reliabi-lity and the coefficient of variation (CV%) as a measure of precision were determined to estimate the reproducibility of RNFL thickness measurements. Results. With all three instruments, the reproducibility of measurements between the superior, inferior, temporal and nasal areas did not differ significantly suggesting that reproducibility does not depend on the thickness of the RNFL. Data obtained by NFA showed the highest ICC values (0.9) and lowest CV% values (7.0), followed by those obtained by HRT (reliability ICC 0.8; precision CV% 12). A markedly lower degree of reproducibility was found for the OCT compared to NFA and HRT (reliability ICC 0.5; precision CV% 15). Conclusion. The comparison of RNFL thickness measurements with OCT, NFA, and HRT showed that the NFA yielded the most reliable results followed by HRT.