Placental transfer of a hydroxylated polychlorinated biphenyl and effects on fetal and maternal thyroid hormone homeostasis in the rat

Earlier studies at our laboratory indicated that several hydroxylated polychlorinated biphenyls (OH-PCBs) detected in human blood could specifically inhibit thyroxine (T4) transport by competitive binding to the thyroid hormone transport protein transthyretin (TTR) in vitro. In the present study we investigated the effects of prenatal exposure to 5 mg/kg body weight of [14C]-labeled or unlabeled 4-OH-2,3,3',4',5-pentachlorobiphenyl (4-OH-CB107), one of the major metabolites of PCBs detected in human blood, from gestation days (GD) 10 to 16 on thyroid hormone status and metabolism in pregnant rats and their fetuses at GD 17 and GD 20. 4-OH-CB107 is a metabolite of both 2,3,3',4,4'-pentachlorobiphenyl (CB-105) and 2,3',4,4',5-pentachlorobiphenyl (CB-118). We were able to show the accumulation of 4-OH-CB107 in the fetal compartment. The fetal/maternal ratios at GD 20 in liver, cerebellum, and plasma were 11.0, 2.6, and 1.2, respectively. The 14C-4-OH-CB107-derived radioactivity in plasma was bound to TTR in both dams and fetuses. Fetal plasma TT4 and FT4 levels were significantly decreased at GD 17 and GD 20 (89 and 41␛espectively at GD 20). Fetal thyroid stimulating hormone levels were increased by 124 at GD 20. The T4 concentrations in fetal forebrain homogenates at GD20 were reduced by 35°but no effects could be detected on brain T3 concentrations. The deiodination of T4 to T3 was significantly increased in fetal forebrain homogenates at GD 17, and unaltered at GD 20. In addition, no alterations were observed in maternal and fetal hepatic T4-UDP-glucuronosyltransferase activity, type I deiodinase activity, and EROD activity. In conclusion, exposure of pregnant rats to 4-OH-CB107 results in the distribution of the compound in the maternal and fetal compartment, which is probably caused by the binding of the PCB metabolite to TTR. Consequently, TT4 levels in fetal plasma and brain samples were reduced. Despite reductions in fetal brain T4 levels, the active hormone (T3) in fetal brains remained unaffected

存貨之估價及其會計上之處理

INTRODUCTION: Osteoporosis (OP) is one of the most prevalent metabolic bone disorders worldwide and it is associated with a higher incidence of fractures. The aim of this study was to identify OP as a risk factor for the development of nonunion. METHODS: In a prospective database all patients aged >50 years with an acute fracture were screened for osteoporosis from September 13, 2004 till February 9, 2009. Bone mineral density measurements (T-scores, Z-scores and absolute values in g/cm(2)) were performed. The selected patients were matched (1:2 ratio) to control patients based on gender, age (+/-5 years) and type of fracture according to the AO-criteria. Other parameters including diabetes mellitus, corticosteroid use, rheumatoid arthritis, smoking, alcohol use, and body mass index were recorded. Follow-up for the patients in the matched group was at least one year. RESULTS: This study included a total of 1498 patients who were screened for the presence of osteoporosis. In total 40 patients were treated for nonunion. After 1:2 matching this resulted in a total number of 120 patients for analysis. Logistic regression analysis including all covariates in the model demonstrated no correlation between the standardised regression coefficients and the development of nonunion (r(2)=0.10, p=0.6). The patients that developed an atrophic nonunion, according to radiographic results, were analysed separately and compared to matched patients. The presence of osteoporosis, osteopenia and normal bone density and the related independent BMD measurements did not differ significantly between the atrophic nonunion group and the matched controls. CONCLUSION: We conclude that although bone quality may be diminished in the elderly this does not influence the occurrence of nonunion. These results indicate that the use of BMD measurements preoperatively to identify osteoporosis as a possible risk factor of nonunion has no clinical value

Impact of low emission zones and local traffic policies on ambient air pollution concentrations

Item does not contain fulltextBACKGROUND: Evaluations of the effectiveness of air pollution policy interventions are scarce. This study investigated air pollution at street level before and after implementation of local traffic policies including low emission zones (LEZ) directed at heavy duty vehicles (trucks) in five Dutch cities. METHODS: Measurements of PM(10), PM(2.5), 'soot', NO(2), NO(x), and elemental composition of PM(10) and PM(2.5) were conducted simultaneously at eight streets, six urban background locations and four suburban background locations before (2008) and two years after implementation of the policies (2010). The four suburban locations were selected as control locations to account for generic air pollution trends and weather differences. RESULTS: All pollutant concentrations were lower in 2010 than in 2008. For traffic-related pollutants including 'soot' and NO(x) and elemental composition (Cr, Cu, Fe) the decrease did not differ significantly between the intervention locations and the suburban control locations. Only for PM(2.5) reductions were considerably larger at urban streets (30%) and urban background locations (27%) than at the matching suburban control locations (20%). In one urban street where traffic intensity was reduced with 50%, 'soot', NO(x) and NO(2) concentrations were reduced substantially more (41, 36 and 25%) than at the corresponding suburban control location (22, 14 and 7%). CONCLUSION: With the exception of one urban street where traffic flows were drastically reduced, the local traffic policies including LEZ were too modest to produce significant decreases in traffic-related air pollution concentrations

Respiratory Effects of a Reduction in Outdoor Air Pollution Concentrations

BACKGROUND:: Air pollution has been associated with respiratory health effects. There is little direct evidence that reductions in air pollution related to abatement policies lead to actual improvement in respiratory health. We assessed whether a reduction in (traffic policy-related) air pollution concentrations was associated with changes in respiratory health. METHODS:: Air pollution concentrations and respiratory health were measured in 2008 and 2010 at eight busy urban streets and at four suburban background control locations. Respiratory function was assessed twice in 661 residents by spirometry and measurements of airway resistance. Nitric oxide (NO) in exhaled air was measured as a marker for airway inflammation. RESULTS:: Air pollution concentrations were lower in 2010 than in 2008. The declines in pollutants varied among locations, with the largest decline observed in a street with a large reduction in traffic intensity. In regression analyses adjusted for important covariates, reductions in concentrations of soot, NO2, NOx, Cu, and Fe were associated with increases in forced vital capacity (FVC) ( approximately 1% increase per interquartile range [IQR] decline). Airway resistance decreased with a decline in particulate matter (PM10) and PM2.5 (9% per IQR), although these associations were somewhat less consistent. No associations were found with exhaled NO. Results were driven largely by one street where traffic-related air pollution showed the largest reduction. Forced expiratory volume and FVC improved by 3% to 6% in residents of this street compared with suburban background residents. This was accompanied by a suggestive reduction in airway resistance. CONCLUSIONS:: Reductions in air pollution may lead to small improvements in respiratory function

An automated algorithm for the detection of cortical interruptions and its underlying loss of trabecular bone; a reproducibility study

Abstract Background We developed a semi-automated algorithm that detects cortical interruptions in finger joints using high-resolution peripheral quantitative computed tomography (HR-pQCT), and extended it with trabecular void volume measurement. In this study we tested the reproducibility of the algorithm using scan/re-scan data. Methods Second and third metacarpophalangeal joints of 21 subjects (mean age 49 (SD 11) years, 17 early rheumatoid arthritis and 4 undifferentiated arthritis, all diagnose