Home About us Contact
|
Home About us Contact | ||
|
|
||
Median Concentration (median + concentration)
Selected AbstractsExposure and effects assessment of resident mink (Mustela vison) exposed to polychlorinated dibenzofurans and other dioxin-like compounds in the Tittabawassee River basin, Midland, Michigan, USA,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 10 2008Matthew J. Zwiernik Abstract Historically, sediments and floodplain soils of the Tittabawassee River (TR; MI, USA) have been contaminated with polychlorinated dibenzofurans (PCDFs), polychlorinated dibenzo- p -dioxins (PCDDs), and polychlorinatedbiphenyls (PCBs). Median concentrations of 2,3,7,8-tetrachlorodibenzo- p -dioxin equivalents (TEQs) based on 2006 World Health Organization tetrachloro-dibenzo- p -dioxin toxic equivalency factors (TEFs) in the diet of mink (Mustela vison) ranged from 6.8 × 10,1 ng TEQ/kg wet weight upstream of the primary source of PCDF to 3.1 × 101 ng TEQ/kg wet weight downstream. Estimates of toxicity reference values (TRVs) derived from laboratory studies with individual PCDDs/PCDFs and PCB congeners or mixtures of those congeners, as well as application of TEFs, were compared to site-specific measures of mink exposure. Hazard quotients based on exposures expressed as concentrations of TEQs in the 95th percentile of the mink diet or liver and the no-observable-adverse-effect TRVs were determined to be 1.7 and 8.6, respectively. The resident mink survey, however, including number of mink present, morphological measures, sex ratios, population age structure, and gross and histological tissue examination, indicated no observable adverse effects. This resulted for multiple reasons: First, the exposure estimate was conservative, and second, the predominantly PCDF congener mixture present in the TR appeared to be less potent than predicted from TEQs based on dose,response comparisons. Given this, there appears to be great uncertainty in comparing the measured concentrations of TEQs at this site to TRVs derived from different congeners or congener mixtures. Based on the lack of negative outcomes for any measurement endpoints examined, including jaw lesions, a sentinel indicator of possible adverse effects, and direct measures of effects on individual mink and their population, it was concluded that current concentrations of PCDDs/PCDFs were not causing adverse effects on resident mink of the TR. [source] Cell-free mRNA concentrations of CRH, PLAC1, and selectin-P are increased in the plasma of pregnant women with preeclampsiaPRENATAL DIAGNOSIS, Issue 8 2007Yuditiya Purwosunu Abstract Objective To compare mRNA concentrations of corticotrophin-releasing hormone (CRH), placenta specific-1 (PLAC1), and selectin-P in preeclamptic and normal pregnancies. Methods Peripheral blood samples were obtained from 43 pregnant women with preeclampsia and 41 control subjects. Plasma was harvested from samples and RNA extracted. Plasma RNA was analyzed using reverse transcription polymerase chain reaction (PCR) assay. Median concentrations of CRH, PLAC1, and selectin-P mRNA in plasma were compared, to assess possible differences in distribution. Data were also stratified and compared according to clinical severity of preeclampsia. Finally, CRH, PLAC1, and selectin-P were plotted against quantitative distributions of blood pressure and proteinuria. Results All markers were differently distributed between cases and controls. Median values in subgroups correlated with severity of preeclampsia. All markers correlated with both. Selectin-P was identified as the marker with the highest degree of correlation. No correlation was found between any markers in the control group and proteinuria or blood pressure. Conclusion CRH, PLAC1, and selectin-P are distributed differently in preeclampsia cases compared to controls and correlate with signs of preeclampsia. Copyright © 2007 John Wiley & Sons, Ltd. [source] Nonylphenols in sediments and effluents associated with diverse wastewater outfalls,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2000Robert C. Hale Abstract Nonylphenols (NPs) have been reported to disrupt endocrine function and sexual development in aquatic organisms at low concentrations. Environmental NP burdens are predominantly derived from degradation of nonylphenol polyethoxylate surfactants. We detected NPs in discharge-associated riverine sediments adjacent to 11 of 20 active sewage treatment plants (STPs) at concentrations up to 12,400 ,g/kg. While most previous studies have focused on STPs, nonylphenols were observed in association with a variety of outfall types. The highest sediment burden, 14,100 ,g/kg, was detected near a federal facility's stormwater discharge. Of 75 sediments examined from 67 sites, 45% contained NP concentrations >5 ,g/kg; median concentration in these NP-positive sediments was 369 ,g/kg. Other surfactant-derived alkylphenolic compounds, specifically 4- tert -octylphenol and 4-cumylphenol, were observed in two sediments at 8,220 and 70,000 ,g/kg, respectively. The maximum NP concentration detected in an effluent, 6,300 ,g/L, was from a shipyard oil/water separator. Nonylphenols were detected (> 1.0 ,g/L) in 20% of the 59 effluents examined; 10% exceeded 10 ,g/L. Sediments sampled near a STP that had ceased treatment operations 20 years prior contained 54,000 ,g/kg, indicative of long-term NP residence. Results indicate that NPs may be released from diverse sources, concentrate in associated sediments, and persist therein for extended periods. [source] Concentration of aluminium in breast cyst fluids collected from women affected by gross cystic breast diseaseJOURNAL OF APPLIED TOXICOLOGY, Issue 1 2009Ferdinando Mannello Abstract Gross cystic breast disease (GCBD) is the most common benign breast disorder, but the molecular basis of cyst formation remains to be identified. If the use of aluminium-based antiperspirant salts is involved in the etiology of gross breast cyst formation, it might be expected that aluminium would be at elevated levels in human breast cyst fluid (BCF). Aluminium was measured by ICP-MS in 48 samples of BCF, 30 samples of human blood serum and 45 samples of human breast milk at different stages of lactation (colostrum, intermediate, mature). The median level of aluminium in apocrine type I BCF (n = 27, 150 µg l,1) was significantly higher than in transudative type II BCF (n = 21, 32 µg l,1; P <0.0001). By comparison, aluminium measurements gave a median concentration of 6 µg l,1 in human serum and 25 µg l,1 in human breast milk, with no difference between colostrum, intermediate and mature milk. Levels of aluminium were significantly higher in both types of BCF than in human serum (P <0.0001). However when compared with human breast milk, aluminium levels were only significantly higher in apocrine type I BCF (P <0.0001) and not in transudative type II BCF (P = 0.152). It remains to be identified why such high levels of aluminium were found in the apocrine type I BCF and from where the aluminium originated. However, if aluminium-based antiperspirants are found to be the source and to play any causal role in development of breast cysts, then it might become possible to prevent this common breast disorder. Copyright © 2008 John Wiley & Sons, Ltd. [source] Bacterial contamination on touch surfaces in the public transport system and in public areas of a hospital in LondonLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2009J.A. Otter Abstract Aims:, To investigate bacterial contamination on hand-touch surfaces in the public transport system and in public areas of a hospital in central London. Methods and Results:, Dipslides were used to sample 118 hand-touch surfaces in buses, trains, stations, hotels and public areas of a hospital in central London. Total aerobic counts were determined, and Staphylococcus aureus isolates were identified and characterized. Bacteria were cultured from 112 (95%) of sites at a median concentration of 12 CFU cm,2. Methicillin-susceptible Staph. aureus (MSSA) was cultured from nine (8%) of sites; no sites grew methicillin-resistant Staph. aureus (MRSA). Conclusions:, Hand-touch sites in London are frequently contaminated with bacteria and can harbour MSSA, but none of the sites tested were contaminated with MRSA. Significance and Impact of the Study:, Hand-touch sites can become contaminated with staphylococci and may be fomites for the transmission of bacteria between humans. Such sites could provide a reservoir for community-associated MRSA (CA-MRSA) in high prevalence areas but were not present in London, a geographical area with a low incidence of CA-MRSA. [source] Impact of maternal circulating cholesterol and gestational diabetes mellitus on lipid metabolism in human term placentaMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 6 2008Charles Marseille-Tremblay Abstract Maternal hypercholesterolemia (HC) during pregnancy and gestational diabetes mellitus (GDM) are associated with disturbance of fetal development which may also modify key features of placental functions. In this study, we evaluated the impact of maternal hypercholesterolemia on placental cholesterol and lipid metabolism in 59 women classified in two groups according to the median concentration of plasma total cholesterol (6.42 mM). The impact of GDM was also evaluated on the metabolism of placentas obtained from 7 insulin-treated GDM and 7 non-GDM women. We showed that high maternal circulating cholesterol is associated with a significant increase in the LDL-cholesterol, ApoB-100 and triglyceride concentrations in the maternal blood. However the level of cholesterol in the venous cord blood and placenta remains unchanged in response to modification in maternal cholesterol profile. The levels of Fatty acid synthase (FAS) and SREBP-2 expressions in placenta are significantly increased in the HC group while expression of both sterol regulatory element-binding proteins-1 (SREBP-1) and HMG-CoA reductase (HMGR) are not modified. GDM is not associated with modification in the maternal lipid profile but it increases the concentration of inflammatory cytokines (IL-1, and TNF-,) in placenta which correlates with a dramatic induction of FAS expression without affecting the expression of mature SREBPs proteins. In conclusion, our study suggests that in placenta, expressions of key proteins involved in de novo lipid synthesis are affected by changes in maternal metabolism (HC and GDM) that may subsequently affect fetal development. Mol. Reprod. Dev. 75: 1054,1062, 2007. © 2007 Wiley-Liss, Inc. [source] T Helper Cell Cytokine Profiles in Preterm LaborAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 3 2004Lisa M. Hollier Problem:, To compare concentrations of T-helper cell cytokines in women with preterm labor (PTL) to normal pregnancies. Method of study:, Fourteen women with PTL and 13 women with normal pregnancies from 24 to 34 weeks were enrolled in this pilot study. Peripheral blood mononuclear cells (PBMCs) and cervical secretions were collected. PBMCs were cultured and stimulated with mitogens. Culture supernatants and cervical secretions were assayed for type 1 (interferon- ,, IL-12) and type 2 cytokines (IL-4, IL-5, IL-10 and IL-13) using enzyme-linked immunosorbent assays. Results:, There were no intergroup differences in median cytokine concentrations in PBMC cultures, or in ratios of type 1/type 2 cytokines. In cervical secretions, the median concentration of IL-4 was significantly higher in control patients. Conclusions:, PTL patients appeared to have an altered T-helper cytokine balance in cervical secretions. Further study of the role of cytokines produced in the adaptive response appears warranted. [source] Cystatin-C and beta trace protein as markers of renal function in pregnancyBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 5 2005Ayub Akbari Objective To assess the validity of Cystatin-C (Cys-C) and beta trace protein (BTP) as clinical markers of glomerular filtration rate (GFR) in pregnant women. Design Prospective cross sectional study. Setting Obstetric unit of a tertiary care hospital. Population One hundred and thirty-seven normal pregnant women and 13 women postpartum. Methods Twenty-four hour creatinine clearance (CrCl), serum creatinine, Cys-C and BTP concentrations were measured on normal pregnant women in the first trimester (n= 5), second trimester (n= 68) and third trimester (n= 64) and in 13 women postpartum. Data are given as median (2.5th centile, 97.5th centile). Main outcome measures Serum concentrations of Cys-C and BTP compared with creatinine clearance and serum creatinine. Results The median serum creatinine throughout gestation was 53 ,mol/L (39, 71), and median CrCl was 143 mL/minute (91 to 216). Postpartum, creatinine rose to 74 ,mol/L (58, 86) and CrCl decreased to 104 mL/minute (71, 159). For Cys-C, the median concentration was 0.70 mg/L (0.46, 1.32), and 0.54 mg/L (0.36, 0.96) for BTP. Comparing the second and third trimesters, there was no significant difference between CrCl (median 145 vs 141 mL/minute) and BTP concentrations (median 0.51 vs 0.55 mg/L), while median Cys-C was significantly higher in the third trimester (0.61 vs 0.88 mg/L; P < 0.001). Unlike creatinine and BTP, Cys-C levels decreased to 0.72 mg/L (0.57, 0.95) postpartum. The only significant relationship of either of these markers to the standard used for GFR was between Cys-C and CrCl in the third trimester, and the correlation was weak (r= 0.27 for 1/Cys-C vs CrCl). Conclusion These data demonstrate that despite claims to the contrary, Cys-C is a poor marker of GFR during pregnancy. Similarly, BTP shows little promise. [source] Salivary gland function in persons with ectodermal dysplasiasEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 5 2003Hilde Nordgarden Ectodermal dysplasias (EDs) constitute a group of conditions comprising developmental defects in two or more of the following tissues: hair, teeth, nails, and sweat glands. The aim of the present study was to contribute to a better understanding of salivary gland involvement in EDs. An ED group (n = 39, median age 12 yr; 24 males, 15 females) and a healthy age- and sex-matched control group were studied. Citric acid stimulated submandibular and parotid salivary flow rates and salivary concentrations, and output of total protein, acidic proline-rich proteins and histatins were analysed. The associations between quantitative and qualitative salivary parameters were also studied. In the ED group, 13 persons (33%) demonstrated a significantly reduced secretion of submandibular and/or parotid saliva, in addition to a low unstimulated and/or chewing-stimulated whole salivary flow. In the ED group as a whole, a reduced median secretory rate of submandibular saliva was found, whereas the median concentrations of some protein parameters were increased. However, the overall output of proteins was normal or reduced. Submandibular glands seemed to be more affected than parotid glands in EDs. In conclusion, salivary secretory tests are recommended in persons with known or suspected EDs. [source] VIRGINIA USA WATER QUALITY, 1978 TO 1995: REGIONAL INTERPRETATION,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 3 2002Carl E. Zipper ABSTRACT: Nine surface water-quality variables were analyzed for trend at 180 Virginia locations over the 1978 to 1995 period. Median values and seasonal Kendall's tau, a trend indicator statistic, were generated for dissolved oxygen saturation (DO), biochemical oxygen demand (BOD), pH (PH), total residue (TR), nonfilterable residue (NFR), nitrate-nitrite nitrogen (NN), total Kjeldahl nitrogen (TKN), total phosphorus (TP), and fecal coliform (FC) at each location. Each location was assigned to one of four physiographic regions, and mean state and regional medians and taus were calculated. Widespread BOD and NFR improvements were detected and FC improvements occurred in the state's western regions. TR and TKN exhibited predominantly increasing trends at locations throughout the state. BOD, TKN, NFR, and TR medians were higher at coastal locations than in other regions. NN, TKN, and TR exhibited predominantly increasing trends in regions with high median concentrations, while declining trends predominated in regions with relatively high BOD, FC, and NFR medians. Appalachian locations exhibited the greatest regional water-quality improvements for BOD, FC, NFR, and TKN. Factors responsible for regional differences appear to include geology, land use, and landscape features; these factors vary regionally. [source] Markers of airway inflammation in primary ciliary dyskinesia studied using exhaled breath condensatePEDIATRIC PULMONOLOGY, Issue 6 2006MRCPCH, Nadwa Zihlif MD Abstract Macroscopically, the airways in primary ciliary dyskinesia (PCD) are inflamed and infected, and the eventual result is bronchiectasis. The measurement of noninvasive markers of inflammation in PCD may allow determination of mechanisms of tissue damage, and even allow monitoring of therapy. The aim of this study was to measure in exhaled breath condensate (EBC) of children with PCD the concentrations of the neutrophil chemoattractants leukotriene (LT) B4 and interleukin (IL)-8 and the marker of oxidative stress 8-isoprostane (8-IP), and to try determining whether these markers can be used to assess mechanisms of airway inflammation in these patients. Concentrations of LTB4, IL-8, and 8-IP in the EBC of 23 PCD and 11 age-matched healthy children were measured using an enzyme immunoassay (EIA). The children also performed spirometry and underwent sputum induction, the latter for differential cell count. The concentrations of 8-IP in EBC of children with stable PCD were significantly increased compared to normal controls (median, 7.8 pg/ml vs. 3.1 pg/ml; P,=,0.004). There was no difference in the median concentrations of EBC LTB4 between PCD subjects and healthy controls (28 pg/ml vs. 28 pg/ml; P,=,0.5). IL-8 levels were below the detection limit of the assay, and were not analyzed further. There was no correlation between concentrations of either 8-IP or LTB4 in EBC and forced expired volume in 1 sec in PCD children. Sputum induction was successful in 83% of the subjects; the median induced sputum neutrophil count was 69% (interquartile range, 59.3,73.6). No significant correlation was found between sputum neutrophils and either EBC 8-IP or LTB4 concentrations in PCD children. This study showed that oxidative stress, as reflected by increased exhaled 8-IP concentration, is increased in PCD children. The mechanism of airway neutrophilia is unclear, but is unlikely to be related to increased production of LTB4, at least in stable PCD patients. Pediatr Pulmonol. © 2006 Wiley-Liss, Inc. [source] Determination of 3,,4,,5,,5,7-pentamethoxyflavone in the plasma and intestinal mucosa of mice by HPLC with UV detectionBIOMEDICAL CHROMATOGRAPHY, Issue 4 2009Hong Cai Abstract In a preliminary experiment 3,,4,,5,,5,7-pentamethoxyflavone (PMF) inhibited adenoma development in ApcMin mice, a model of the human heritable condition familial adenomatous polyposis. An HPLC method for tricin was modified and validated to permit measurement of PMF in mouse plasma and intestinal mucosa. HPLC analysis was carried out on a Hypersil-BDS C18 column with detection at 324 nm and tricin as internal standard. The assay was linear in the range of 100,2000 ng/mL plasma and 1.0,40 µg/mL mucosa. PMF in plasma was efficiently extracted using solid-phase columns. In the case of mucosa organic solvent protein precipitation displayed satisfactory accuracy and precision. The assay recovery at low, medium and high concentrations was between 85 and 103% for both biomatrices, with a relative standard deviation of <15%. The lower limits of quantitation for plasma and mucosa were 100 ng/mL and 1.0 µg/mL, respectively. This method allowed measurement of PMF steady-state median concentrations in plasma (1.08 nmol/mL, n = 11; 10th and 90th percentiles: 0.633 and 2.385 nmol/mL) and mucosa (108.5 nmol/g, n = 9; 10th and 90th percentiles: 38.9 and 164.4 nmol/g) in mice which had received PMF (0.2%, w/w) with their diet. Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||||||||