bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulation of Growth Plate Chondrocytes by 1,25-Dihydroxyvitamin D3 Requires Caveolae and Caveolin-1
Authors: Boyan Barbara D , Wong Kevin L , Wang Liping , Yao Hai , Guldberg Robert E , Drab Marek , Jo Hanjoong , Schwartz Zvi
Published: September 2006

We examined the role of caveolae and caveolin-1 in the mechanism of 1α,25(OH)2D3 action in growth plate chondrocytes. We found that caveolae are required for rapid 1α,25(OH)2D3-dependent PKC signaling, and caveolin-1 must be present based on studies using chondrocytes from Cav-1−/− mice.

Introduction: 1,25-dihydroxyvitamin D3 [1α,25(OH)2D3] regulates endochondral ossification in part through membrane-associated mechanisms, including protein kinase C (PKC) signaling activated by a membrane-associated 1α,25(OH)2D3-binding protein, ERp60. We tested the hypothesis that caveolae are required for 1α,25(OH)2D3 action and play an important role in regulating chondrocyte biology and growth plate physiology.

Materials and Methods: Rat costochondral chondrocytes were examined for caveolae by transmission electron microscopy of cultured cells and of cells in situ. Western blots and confocal microscopy were used to detect caveolae proteins including caveolin-1 (Cav-1) and 1α,25(OH)2D3 receptors. Caveolae cholesterol was depleted with β-cyclodextrin (CD) and effects of 1α,25(OH)2D3 on PKC, DNA synthesis, alkaline phosphatase, and proteoglycan production determined. Chondrocytes from Cav-1−/− and C57BL/6 wildtype mice were also treated with 1α,25(OH)2D3. Epiphyses and costochondral junctions of 8-week-old male Cav-1−/− and wildtype mice (N = 8) were compared by histomorphometry and μCT. Data were analyzed by ANOVA and Bonferroni for posthoc comparisons.

Results: Growth zone chondrocytes had caveolae and Cav-1, −2, and −3. Resting zone chondrocytes, which do not exhibit a rapid 1α,25(OH)2D3-dependent increase in PKC activity, also had these caveolins, but caveolae were larger and fewer in number. ERp60 but not VDR co-localized with Cav-1 in plasma membranes and in lipid rafts. CD-treatment blocked 1α,25(OH)2D3 effects on all parameters tested. The Cav-1−/− cells did not respond to 1α,25(OH)2D3, although 1α,25(OH)2D3 increased PKC, alkaline phosphatase, and [35S]-sulfate incorporation in wildtype C57BL/6 cells. Histology and μCT showed that Cav-1−/− growth plates were longer and had more hypertrophic cells in each column. Growth plate changes were reflected in the metaphysis.

Conclusions: The membrane-mediated effects of 1α,25(OH)2D3 require caveolae and Cav-1, and Cav-1 deficiency results in altered growth plate physiology.
Genomic Regions Identified for BMD in a Large Sample Including Epistatic Interactions and Gender-Specific Effects
Authors: Xiao Peng , Shen Hui , Guo Yan-Fang , Xiong Dong-Hai , Liu Yao-Zhong , Liu Yong-Jun , Zhao Lan-Juan , Long Ji-Rong , Guo Yan , Recker Robert R , Deng Hong-Wen
Published: September 2006

A genome-wide linkage scan was conducted using a large white sample to identify QTLs for BMD. We found QTLs in the total sample and the gender-specific subgroups, as well as significant epistatic interactions underlying BMD variations.

Introduction: Low BMD is an important risk factor for osteoporosis and under strong genetic control.

Materials and Methods: To identify quantitative trait loci (QTLs) for regulation of BMD, we performed a large-scale whole genome linkage scan (WGS) involving 4126 individuals from 451 families. In addition to the conventional linkage analyses in the total combined sample of males and females, we conducted epistatic interaction analyses and gender-specific linkage analyses.

Results: Significant linkage was detected on 5q23 for wrist BMD (LOD = 3.39) and 15q13 for female spine BMD (LOD = 4.49). For spine BMD, we revealed significant epistatic interactions between 3p25 and 2q32 (p = 0.0022) and between 3p25 and 11q23 (p = 0.0007). We replicated several genomic regions that showed linkage with BMD in previous studies by others and ours, such as 3p21, 1p36, and Xq27.

Conclusions: This study highlights the importance of large sample size, incorporation of epistatic interaction, and consideration of gender-specific effects in identifying QTLs for BMD variation. The results of this study provide a foundation for the future fine mapping and gene identification in our population.
α9β1: A Novel Osteoclast Integrin That Regulates Osteoclast Formation and Function
Authors: Rao Hongwei , Lu Ganwei , Kajiya Hiroshi , Garcia-Palacios Veronica , Kurihara Noriyoshi , Anderson Judy , Patrene Ken , Sheppard Dean , Blair Harry C , Windle Jolene J , Choi Sun Jin , Roodman G David
Published: September 2006

We identified a previously unknown integrin, α9β1, on OCLs and their precursors. Antibody to α9 inhibited OCL formation in human marrow cultures, and OCLs from α9 knockout mice had a defect in actin ring reorganization and an impaired bone resorption capacity.

Introduction: Integrins play important roles in osteoclast (OCL) formation and function. Mature OCLs mainly express αvβ3 integrin, a heterodimer adhesion receptor that has been implicated in osteoclastic bone resorption. We identified ADAM8, a disintegrin and metalloproteinase, as a novel stimulator of OCL differentiation and showed that the disintegrin domain of ADAM8 mediated its effects on OCL formation. Because the disintegrin domain of ADAM8 does not bind Arg-Gly-Asp (RGD) sequences, we determined which integrin bound ADAM8 and characterized its role in OCL formation and activity.

Materials and Methods: Chinese hamster ovary cells (CHO) expressing different integrin subunits were tested for their capacity to bind the disintegrin domain of ADAM8. Mouse or human bone marrow cells and purified OCL precursors were tested for α9β1 integrin expression by Western blot, immunocytochemistry, and real-time RT-PCR. A monoclonal antibody to human α9 was used to block α9β1 on OCL precursors stimulated by 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3] or RANKL. Vertebrae of 7-day-old α9−/− mice and wildtype (WT) littermates were compared using bone histomorphometry and 3D μCT analysis.

Results: α9 integrin was expressed by mouse and human bone marrow–derived OCLs and their precursors. Importantly, the anti-α9 antibody inhibited human OCL formation stimulated by 1α,25(OH)2D3 or RANKL dose-dependently. Furthermore, analysis of OCLs formed in marrow cultures from α9−/− mice showed that the OCLs formed were more contracted and formed significantly less bone resorption pits on dentin slices. Histologic analysis of α9−/− vertebrae showed thickened trabecular regions and retained cartilage within vertebral bodies of α9−/− mice. 3D μCT analysis of α9−/− vertebrae also showed a significant increase in trabecular bone volume/total tissue volume and a tendency for decreased trabecular separation compared with WT mice.

Conclusions: These results support a previously unknown role for α9β1 integrin in OCL formation and function.
Reproducibility of Risk Figures in 2nd-Trimester Maternal Serum Screening for Down Syndrome: Comparison of 2 Laboratories
Authors: Benn Peter A , Makowski Gregory S , Egan James FX , Wright Dave
Published: September 2006

Background: Analytical error affects 2nd-trimester maternal serum screening for Down syndrome risk estimation. We analyzed the between-laboratory reproducibility of risk estimates from 2 laboratories.

Methods: Laboratory 1 used Bayer ACS180 immunoassays for α-fetoprotein (AFP) and human chorionic gonadotropin (hCG), Diagnostic Systems Laboratories (DSL) RIA for unconjugated estriol (uE3), and DSL enzyme immunoassay for inhibin-A (INH-A). Laboratory 2 used Beckman immunoassays for AFP, hCG, and uE3, and DSL enzyme immunoassay for INH-A. Analyte medians were separately established for each laboratory. We used the same computational algorithm for all risk calculations, and we used Monte Carlo methods for computer modeling.

Results: For 462 samples tested, risk figures from the 2 laboratories differed >2-fold for 44.7%, >5-fold for 7.1%, and >10-fold for 1.7%. Between-laboratory differences in analytes were greatest for uE3 and INH-A. The screen-positive rates were 9.3% for laboratory 1 and 11.5% for laboratory 2, with a significant difference in the patients identified as screen-positive vs screen-negative (McNemar test, P <0.001). Computer modeling confirmed the large between-laboratory risk differences.

Conclusion: Differences in performance of assays and laboratory procedures can have a large effect on patient-specific risks. Screening laboratories should minimize test imprecision and ensure that each assay performs in a manner similar to that assumed in the risk computational algorithm.
Measurement of Urinary Metanephrines to Screen for Pheochromocytoma in an Unselected Hospital Referral Population
Authors: Brain Keith L , Kay Jonathan , Shine Brian
Published: September 2006

Background: Despite the rarity of pheochromocytoma, diagnosis is important because of the dangers of uncontrolled severe hypertension and the availability of very effective surgical treatment. Urinary or plasma catecholamines or catecholamine derivatives are commonly used to screen for pheochromocytomas before imaging, but data from 24-h urinary metanephrine results, patient age, and sex may better predict tumors in populations with a low pretest probability.

Methods: We retrospectively studied outcomes of an unselected population (1819 patients) referred to a tertiary hospital laboratory for urinary metanephrine testing and investigated the usefulness of some simple derivative measures for detecting pheochromocytoma. We normalized values for urinary 24-h excretion of metanephrine, normetanephrine, and 3-methoxytyramine by dividing by an age- and sex-specific reference range. We then compared pheochromocytoma prediction by the use of products of these normalized measures with the gold standard of biopsy-confirmed tumor.

Results: The product of the excretion of normalized metanephrine (nMAD) and normalized normetanephrine (nNMT) (nMAD·nNMT) was a highly sensitive (100%) and specific (99.1%) measure, yielding a positive predictive value of 82%. ROC curves were not improved by including the normalized 3-methoxytyramine concentrations in the product. The test for nMAD·nNMT gave higher sensitivity and specificity than the tests for either substance alone.

Conclusion: The test for nMAD·nNMT is a useful measure for identifying pheochromocytoma in a population with a low pretest probability.
Rapid, Simple, and Sensitive Immunoagglutination Assay with SiO2 Particles and Quartz Crystal Microbalance for Quantifying Schistosoma japonicum Antibodies
Authors: Wang Hua , Zhang Yun , Yan Bani , Liu Li , Wang Shiping , Shen Guoli , Yu Ruqin
Published: September 2006

Background: The resurgence of the parasitic disease schistosomiasis calls for more efficient diagnostic tests. We developed a rapid, simple, portable, and sensitive immunoagglutination assay that uses SiO2 particles and quartz crystal microbalance (QCM) for quantifying Schistosoma japonicum (Sj) antibodies (SjAb).

Methods: We prepared submicrometer-sized silica particles derivatized with Sj antigens as replacements for traditional latex microspheres to specifically agglutinate in the presence of SjAb targets, and we used the QCM monitor to measure the resulting frequency shifts. We optimized the assay medium by adding poly(ethylene glycol) (PEG) as a response accelerator of immunoagglutination. To minimize or eliminate any nonspecific agglutination or adsorption interferences, we conducted appropriate sealing procedures separately for silica particles and the QCM probe.

Results: The measured frequency changes were linearly related to the SjAb concentrations in infected rabbit serum. The PEG-assisted immunoagglutination system was quantitatively sensitive to SjAb concentrations ranging from ∼0.70 to 32.31 mg/L, with a detection limit of ∼0.46 mg/L. The obtained linear regression equation was: y = 43.61 x + 80.44 (r = 0.9872). Several serum specimens were evaluated with the developed QCM immunoassay and the results were compared with ELISA, validating the feasibility of practical applications.

Conclusions: This novel immunoagglutination-based QCM detection format is rapid, simple to use, and more portable than conventional diagnostic immunoassays, thus offering a promising alternative tool that can be used for point-of-care clinical diagnosis of schistosomiasis, particularly in epidemic situations.
Improvement of Technical and Analytical Performance in DNA Sequencing by External Quality Assessment-Based Molecular Training
Authors: Dorn-Beineke Alexandra , Ahmad-Nejad Parviz , Pfeiffer Ulrike , Ramsden Simon , Pazzagli Mario , Neumaier Michael
Published: September 2006

Background: From 2003 to 2005, the European Union supported the EQUAL-initiative to develop methodological external quality assessment (EQA) schemes for genotyping (EQUALqual), quantitative PCR (EQUALquant), and sequencing (EQUALseq). As a relevant part of the EQUALseq program, a training course was held subsequent to the first EQA Program (EQAP1). The success of this course was reassessed in a 2nd EQUALseq round (EQAP2).

Methods: In September 2005, a 3-day training course took place. We invited 8 laboratories with below-average performance in EQAP1 to improve their methodological and analytical/proficiency skills by lectures and practical work. To compare the results of the pretraining and posttraining EQUALseq rounds, we distributed 2 samples used in the first EQUAL round, but this time we provided different oligonucleotide sets. We evaluated the results by means of a previously described scoring system.

Results: In EQAP2, 6 laboratories returned complete data sets, corresponding to an overall 14% of the 43 laboratories that had finished EQAP1. The scoring results for samples A (P = 0.0025) and B (P = 0.0125) demonstrated a significant improvement in EQAP2. Overall, a substantial improvement of technical and interpretative skills was demonstrated (P = 0.0051). In general, the workshop experience was highly rated by the participants.

Conclusions: Methodologic EQAPs in DNA sequencing are appropriate tools to uncover strengths and weaknesses in both technique and proficiency, emphasizing the need for mandatory EQAPs. Training courses, together with 2nd-round reiterations, should be implemented into methodological EQAPs in molecular diagnostics to improve technical performance and proficiency in genetic testing.
Circulating Proteasomes Are Functional and Have a Subtype Pattern Distinct from 20S Proteasomes in Major Blood Cells
Authors: Zoeger Annette , Blau Michael , Egerer Karl , Feist Eugen , Dahlmann Burkhardt
Published: September 2006

Background: 20S proteasomes, the proteolytic core particles of the major intracellular protein degradative pathway, are potential disease markers because they are detectable in human plasma as circulating proteasomes and their concentrations are increased in patients suffering from various diseases. To investigate the origin of circulating proteasomes, we compared some of their features with those of proteasomes isolated from major blood cells.

Methods: We isolated circulating proteasomes from the plasma of 2 patients with rheumatoid arthritis and 2 with systemic lupus erythematosus and from human plasma from healthy donors. We purified the proteasomes to apparent homogeneity and then used electron microscopy for imaging and chromatography for subtype spectrum analysis. We compared subtype results with those from 20S proteasomes purified from 4 major blood cell populations. We also tested proteasomes for enzymatic activity and immunosubunit content.

Results: Circulating proteasomes from plasma of healthy donors and from patients with autoimmune disease were found to have the same size and shape as erythrocyte proteasomes, be proteolytically active, and contain standard- and immunosubunits. Chromatography revealed 6 circulating proteasome subtype peaks in healthy donor plasma and 7 in patient donor plasma. Proteasomes from erythrocytes had 3 subtype peaks and those of monocytes, T-lymphocytes, and thrombocytes each had 5 different subtype peaks.

Conclusion: Circulating proteasomes were intact and enzymatically active in plasma from healthy donors and from patients with autoimmune disease. Because the subtype patterns of circulating proteasomes clearly differ from those of proteasomes from blood cells, these cells cannot be regarded as a major source of circulating proteasomes.
Lipoprotein(a) in the Cerebrospinal Fluid of Neurological Patients with Blood–Cerebrospinal Fluid Barrier Dysfunction
Authors: Pepe Gabriella , Chimienti Guglielmina , Liuzzi Grazia Maria , Lamanuzzi Biagia Leila , Nardulli Marina , Lolli Francesco , Anglés-Cano Eduardo , Matà Sabrina
Published: September 2006

Background: Lipoprotein(a) [Lp(a)] is a recognized pathogenic particle in human plasma, but its presence in the cerebrospinal fluid and its possible role in the central nervous system have not been documented. We tested the hypothesis that apolipoprotein(a) [apo(a)], free or as a component of the Lp(a) particle, can cross the blood–cerebrospinal fluid barrier and be found in the cerebrospinal fluid of patients affected by neurologic pathologies.

Methods: We studied paired cerebrospinal fluid/serum samples from 77 patients with inflammatory (n = 20) or noninflammatory (n = 34) blood–cerebrospinal fluid barrier dysfunction and without blood–cerebrospinal fluid barrier dysfunction (n = 23). We used ELISA to measure Lp(a) concentrations and Western blot and immunodetection to analyze apo(a) isoforms in native and reducing conditions.

Results: Entire Lp(a) with either small or large apo(a) isoforms was present in the cerebrospinal fluid of patients with blood–cerebrospinal fluid barrier dysfunction, regardless of its pathogenesis. Multiple linear regression analysis showed that both serum Lp(a) concentration (P = 0.003) and cerebrospinal fluid/serum albumin ratio (P <0.001) were predictors of the Lp(a) concentration in cerebrospinal fluid.

Conclusions: Our results demonstrate that Lp(a) can cross a dysfunctional blood–cerebrospinal fluid barrier. The unusual presence of Lp(a) in the cerebrospinal fluid could extend some of its known pathogenic effects to the central nervous system.
Inhibitory Effects of Micronized Fenofibrate on Carotid Atherosclerosis in Patients with Essential Hypertension
Authors: Zhu Shiming , Su Guohai , Meng Qing H
Published: September 2006

Background: The coexistence of hypertension and dyslipidemia synergistically increases the risk of cardiovascular events. We investigated the effect of the lipid-lowering agent micronized fenofibrate on inhibition of carotid atherosclerosis in patients with essential hypertension and mild hyperlipidemia.

Methods: We measured serum lipid profiles and inflammatory markers on chemistry or immune analyzers and common or internal carotid intima-media thickness (IMT) and diameter (D) by ultrasonography.

Results: Patients receiving micronized fenofibrate for 24 months in addition to antihypertensive treatment had decreased concentrations of total cholesterol, LDL-cholesterol, triglyceride, apolipoprotein B100, oxidized LDL, high-sensitivity C-reactive protein, P-selectin, and cytokines. These patients had increased concentrations of HDL-cholesterol, apolipoprotein A-I, and nitric oxide. Common carotid artery IMT (CCAIMT) and internal carotid artery IMT (ICAIMT) remained unchanged during the 24-month intervention. Moreover, the mean CCAIMT/D ratio and ICAIMT/D ratio were significantly decreased in the fenofibrate intervention group. In contrast, CCAIMT/D and ICAIMT/D ratios were increased in the control group. The incidence rates of carotid artery plaque formation and stroke in the fenofibrate intervention group were significantly lower than those in the control group.

Conclusion: The combination of antihypertensive agents with micronized fenofibrate can effectively prevent the progression of carotid atherosclerosis and reduce the incidence of stroke in patients with essential hypertension.
Dppa2 and Dppa4 Are Closely Linked SAP Motif Genes Restricted to Pluripotent Cells and the Germ Line
Authors: Maldonado-Saldivia Joanna , van den Bergen Jocelyn , Krouskos Margarita , Gilchrist Mike , Lee Caroline , Li Ruili , Sinclair Andrew H. , Surani M. Azim , Western Patrick S.
Published: September 2006

Despite the enormous medical potential of ESCs, the molecular mechanisms conferring the ability to differentiate into all cell types of the embryo remain elusive. We used an in silico approach to identify genes expressed exclusively in mouse preimplantation embryos and pluripotent cell lines. Two of these genes were developmental pluripotency-associated gene 2 (Dppa2) and Dppa4, which we show are closely linked genes encoding putative nuclear SAP domain proteins expressed in human and mouse pluripotent stem cells and germ cell tumor-derived embryonal carcinoma cells. In the mouse, these genes are transcribed in germinal vesicle-stage oocytes and throughout the cleavage stages of embryogenesis. They then become restricted to the pluripotent inner cell mass of blastocysts and are subsequently downregulated. After gastrulation, Dppa2 and Dppa4 are expressed only in the developing germ line, showing that these genes mark cells of the pluripotent cycle. In the germ line, both genes are downregulated as the germ cells commit to the oogenic pathway or soon after commitment to the spermatogenic pathway. We have observed similar germ line expression profiles for other pluripotent markers, and these results are consistent with the hypothesis that pluripotent markers must be downregulated during fetal germ line development, a process that may be required to facilitate appropriate germ line differentiation. The study of expression and function of pluripotent markers such as Dppa2 and Dppa4 is likely to unveil new aspects of the regulation of pluripotency and germ line development in mammals.
Specifying Scale‐dependent Dispersivity in Numerical Solutions of the Convection–Dispersion Equation
Authors: Wang Huaguo , Persaud Naraine , Zhou Xiaobo
Published: September 2006

Many studies have incorporated various scale‐dependent dispersivity functions into the convection–dispersion equation (CDE). For a given function, there are different ways of specifying the dispersivity values in the discretized subdomains of a numerical solution. These ways would depend on how the function's time or space variable is built into the numerical scheme and on how the different ways may be interrelated. No study has addressed how these different ways may affect resulting breakthrough curves (BTCs) or their applicability to solute transport problems. In this study, five ways were specified and designated as local time, average time, apparent time, local distance, or apparent distance dependent dispersivity in the numerical scheme. The main objective was to demonstrate relationships among these ways by assuming that dispersion in the scale‐dependent CDE was quasi‐Fickian and implicitly based on an estimation of the first moment of the BTC at the given location. How these ways affected calculated BTCs was numerically tested using generalized linear and power scale–dependent dispersivity functions for a one‐dimensional problem with initial solute distribution represented as a Dirac delta function. For either type of function, differences were obvious in BTCs obtained for solute transport conditions with small apparent Peclet numbers using the alternative ways of specifying scale‐dependent dispersivity in the numerical scheme. The differences decreased with increasing apparent Peclet number. The numerical test results also showed that the derived relationships were not applicable for numerically calculating the spatial solute distribution at a given time. These test results were expected to be generally applicable because any other initial‐value solute transport problem can be solved as a superposition of this test problem.
Winter Cereal–Corn Double Crop Forage Production and Phosphorus Removal
Authors: Brown Bradford D.
Published: September 2006

Maximizing P removal with cropping can increase regulated P‐based manuring rates or reduce soil test P in manure‐enriched soils. The potential for increased P removal with winter forage–corn silage double cropping was evaluated in a 3‐yr study at Parma, ID. Winter barley (Hordeum vulgare L.), and both winter and spring genotypes of wheat (Triticum aestivum L.) and triticale (×Triticosecale Wittmack) were fall planted at three seeding rates (112, 168, or 224 kg ha−1) and followed with silage corn (Zea mays L.). Corn alone and a noncropped treatment were included. Winter forages were harvested near boot stage. Seeding rates of 168 kg ha−1 were necessary for maximizing winter forage production but had little effect on P uptake. Winter forage production and P content were highly year dependent due largely to appreciable winterkill of spring wheat and winter barley in 1999. Winter forage P concentrations, unlike those for corn, decreased with successive harvests. Cumulative P uptake ranged as high as 65.7 kg ha−1 for winter triticale. Winter forages reduced corn yields in 2 of 3 yr and corn P uptake in 1 yr. Compared to corn alone, double cropping increased cumulative forage production from 8.4 to 15.9% and total P removal by 29.8 to 42.2%. Soil test P concentrations after 3 yr decreased more with double cropping than with corn alone. Half of the P decline was unrelated to P uptake and removal. Double cropping can increase total forage production, P removal, and hasten soil test P decline.
Hydrological Control of Phosphorus Mobility in Altered Wetland Soils
Authors: Litaor M. Iggy , Eshel G. , Reichmann O. , Shenker M.
Published: September 2006

Ground water transport of P from the altered wetland soils of the Hula Valley may influence the water quality of Lake Kinneret, which provides up to 30% of the potable water for the state of Israel. We hypothesized that land use change in these altered wetland soils is the cause for the reported increase in particulate P loading to the Jordan River, which empties to Lake Kinneret. To test this hypothesis we evaluated the P mobility from the Hula's wetland soils to waterways under various hydrological conditions using a field‐scale experiment (0.8 km2) with well‐monitored boundary conditions. The spatiotemporal changes in hydraulic head across the study area were measured using automated monitoring stations installed in eight observation wells. The hydraulic conductivity (K) of the near‐surface peat/marl layers (179 m d−1) was significantly larger than theKvalues (0.001 to 0.03 m d−1) measured in the marl layers at 5 to 15 m below surface. The large K values of the near‐surface layers result from the drainage of this wetland in the late 1950s followed by the oxidation of the peat layers and dissection of the lower peat and upper silt‐clayey marl layers. Using a simple water‐budget approach, the large field experiment yielded a discharge of 0.27 Mm3and a loading of 306 kg P transported from the altered peat soils to the waterways, in just 7 wk. Most of the P loading was in the form of particulate P (>0.45 μm) rather than dissolved P.
Effects of Increasing Potassium Chloride and Calcium Chloride Ionic Strength on Pesticide Sorption by Potassium‐ and Calcium‐Smectite
Authors: Li Hui , Teppen Brian J. , Laird David A. , Johnston Cliff T. , Boyd Stephen A.
Published: September 2006

In aqueous suspension, the affinity of many pesticides for smectites is influenced by the clay properties such as surface area, surface charge density and location, exchangeable cations, and hydration status of exchangeable cations in clay interlayers. The amount and the type of salts present in the aqueous phase influence clay quasicrystal structures and hydration status, which we hypothesize as major determinants of pesticide sorption. To test this hypothesis, we measured sorption isotherms of alachlor, atrazine, dichlobenil, and diuron by K+–saturated smectite (K‐SWy‐2) in KCl solution and Ca2+–saturated smectite (Ca‐SWy‐2) in CaCl2 solution at several ionic strengths. The results indicated that pesticide sorption by K‐SWy‐2 significantly increased with increasing aqueous KCl concentration. In contrast, sorption by Ca‐SWy‐2 at different CaCl2 ionic strengths remained nearly constant. The “salting‐out” effect on the reduction of dissolution of pesticides failed to account for the significantly increased sorption by K‐SWy‐2 in aqueous KCl solutions. We conclude that formation of better‐ordered clay quasicrystals and shrinkage of clay interlayer distance owing to increased KCl ionic strength facilitate the intercalation of pesticides leading to greater sorption by the clay, while the salting‐out effect plays a minor role (if any) in the observed sorption enhancement.
Trace Element Mobilization in Soils by Glyphosate
Authors: Barrett K. A. , McBride M.B.
Published: September 2006

Glyphosate, the most widely used herbicide in agriculture, has a strong tendency to sorb on minerals by bonding with surface metals through its metal‐coordinating functional groups. However, this same chemical process can potentially mobilize sorbed trace metals by chelation and sorbed anions such as phosphate by displacement. The tendency for glyphosate to mobilize Cu and other elements was tested in soil leaching experiments by applying glyphosate alone or complexed with Cu to mineral and organic soil columns and measuring the concentrations of these elements in the leachates by inductively coupled plasma (ICP) spectrophotometry. Complexation with glyphosate inhibited Cu sorption on the soil columns, rendering this metal more mobile in both the mineral and organic soil. Glyphosate mobility was also enhanced when applied to the organic soil as the Cu complex, but this effect was not detected with the mineral soil. Glyphosate was adsorbed more completely on the organic soil than the mineral soil, suggesting a metal bridging mechanism to explain sorption of this anionic molecule. The application of a commercial Roundup spray to long‐contaminated soils containing elevated concentrations of heavy metals and phosphate resulted in significant increases in the leaching of Cu, Zn, Al, Ni, P, Si, and As. No significant increases in elemental leaching were detected in mineral and organic soils with normal background concentrations of heavy metals and P. Batch equilibration studies confirmed the glyphosate‐enhanced dissolution of Cu in Cu‐contaminated soils, but reductions of free Cu2+ activity were measured only in uncontaminated soils. The results indicate that several elements, particularly Cu, Al, and P, could be mobilized within the thin surface layer of soils receiving a high effective rate of glyphosate during herbicide application.
Multiscale modeling of transport and residence times in nanostructured membranes
Authors: Albo Simón E. , Broadbelt Linda J. , Snurr Randall Q.
Published: September 2006

Modeling and simulation at different scales were used to study mass transport and residence times of particles in nanostructured membranes with uniform cylindrical pores of 10–150 nm diameter and up to 5 μm long. Analytical equations of the possible mass‐transport mechanisms inside the pores were used to determine that diffusion dominates over convection under the conditions of interest for selective oxidation: 700 K and pressure near atmospheric. Molecular dynamics simulations showed that surface diffusion is present only at temperatures < 700 K. Knudsen diffusion was identified as the dominant mechanism. Simulations based on its principles were performed using an ensemble of particles in a boundary‐driven simulation cell, providing the average number of hits between a particle and the pore wall and the dependency of the residence time on the pore dimensions. The differences between operating a nanostructured membrane reactor in sweep‐gas and pass‐through modes were also investigated. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Extending the Scope of NMR Spectroscopy with Microcoil Probes
Authors: Schroeder Frank C. , Gronquist Matthew
Published: September 2006

Capillary NMR (CapNMR) spectroscopy has emerged as a major breakthrough for increasing the mass‐sensitivity of NMR spectroscopic analysis and enabling the combination of NMR spectroscopy with other analytical techniques. Not only is the acquisition of high‐sensitivity spectra getting easier but the quality of CapNMR spectra obtained in many small‐molecule applications exceeds what can be accomplished with conventional designs. This Minireview discusses current CapNMR technology and its applications for the characterization of mass‐limited, small‐molecule and protein samples, the rapid screening of small‐molecule or protein libraries, as well as hyphenated techniques that combine CapNMR with other analytical methods.
Luminescent lanthanide molecular‐based hybrid materials bridged through novel urethane linkages
Authors: Yan Bing , Zhou Bing , Wang Qian‐Ming
Published: September 2006

Novel organosilicates with covalently linked functional modified aromatic acid have been synthesized from 3‐aminopropyl triethoxysilane (APS) grafted 4‐ethoxy benzoic acid (EB‐Si) and terbium ions via a simple low‐temperature route. The existence of covalent bonds between EB‐Si and silica matrices was shown by the hydrolysis and polycondensation processes of ethoxysilyl groups. Luminescence spectra were used to characterize the photophysical properties of the obtained hybrid material and the above spectroscopic data reveal that the triplet energy of modified para ethoxy benzoic acid in this favorable hybrid system matches the emissive energy level of RE3+. Copyright © 2006 John Wiley & Sons, Ltd.
Heck reactions of aryl halides with alk‐1‐en‐3‐ol derivatives catalysed by a tetraphosphine–palladium complex
Authors: Berthiol Florian , Doucet Henri , Santelli Maurice
Published: September 2006

cis,cis,cis‐1,2,3,4‐Tetrakis(diphenylphosphinomethyl)cyclopentane–[PdCl(C3H5)]2 efficiently catalyses the Heck reaction of alk‐1‐en‐3‐ol with a variety of aryl halides. In the presence of hex‐1‐en‐3‐ol or oct‐1‐en‐3‐ol, the β‐arylated carbonyl compounds were selectively obtained. Turnover numbers up to 84 000 can be obtained for this reaction. Linalool and 2‐methylbut‐3‐en‐2‐ol led regio‐ and stereoselectively to the corresponding (E)‐1‐arylalk‐1‐en‐3‐ol derivatives. A minor electronic effect of the substituents of the aryl bromide was observed. Quite similar reaction rates were generally observed in the presence of activated aryl bromides such as bromoacetophenone and deactivated aryl bromides such as bromoanisole, indicating that, with these alkenols and this catalyst, the oxidative addition of aryl bromides to palladium is not the rate‐limiting step. It should be noted that this reaction also proceeds with sterically very congested aryl bromides such as 9‐bromoanthracene or 2,4,6‐triisopropylbromobenzene or with a vinyl bromide. On the other hand, low yields were obtained with aryl chlorides. Copyright © 2006 John Wiley & Sons, Ltd.
Novel photoswitching dithienylethenes with ferrocene units
Authors: Yin Jun , Yu Guang‐Ao , Tu Haiyang , Liu Sheng Hua
Published: September 2006

Two novel dithienylethenes with ferrocene units were synthesized by Wittig reaction. The structure of 2a has been established by X‐ray diffraction studies. They could reversibly interconvert between two thermally stable forms, an open and a closed one, using light of different wavelengths as triggers. Copyright © 2006 John Wiley & Sons, Ltd.
Decoupling the past from the present attenuates inaction inertia
Authors: van Putten Marijke , Zeelenberg Marcel , van Dijk Eric
Published: September 2006

Inaction inertia is the phenomenon that one is not likely to act upon an attractive opportunity after having bypassed an even more attractive opportunity. We investigated the boundary conditions of this inaction inertia effect. Based on the mental accounting literature and the transaction decoupling literature we predicted and found in three experiments that tight coupling of the forgone to the current opportunity is a necessary condition for inaction inertia to occur. Inaction inertia decreased when information about the missed opportunity was ambiguous (Experiment 1), when the past opportunity required an extra step to obtain (Experiment 2) and when the past and present opportunity decreased in comparability (Experiment 3). The theoretical and practical implications of the results are discussed in view of the literature on inaction inertia and on judgment and decision‐making. Copyright © 2006 John Wiley & Sons, Ltd.
Risks of hyperthermia associated with hot tub or spa use by pregnant women
Authors: Chambers Christina D.
Published: September 2006

There are a limited number of human studies linking hot tub or spa use during early pregnancy to increased risks for neural tube defects (NTDs) or spontaneous abortion. However, these data can be considered in the context of human studies that have demonstrated an association between high maternal fever in early pregnancy and NTDs. In addition, there is a large volume of animal literature suggesting that, regardless of the heat source, an elevated core maternal temperature at or above the threshold of 2°C over baseline, as well as timing and duration of exposure, are the critical factors in conferring risk. Therefore, the potential for hot tub or spa use to increase core maternal body temperature to risky levels and thus increase the risk for NTDs is likely. A woman who knows or who may not yet be aware that she is pregnant should be advised of the recommended limits of exposure. She should also be aware of the possible variability in hot tub or spa temperature readings and be able to accurately monitor maximum water temperature in the hot tub or spa so that her body temperature can be maintained below 38.9°C. Birth Defects Research (Part A) 76:569–573, 2006. © 2006 Wiley‐Liss, Inc.
Searching for the regulators of human gene expression
Authors: Forton Julian T. , Kwiatkowski Dominic P.
Published: September 2006

Many common human traits are believed to be a composite reflection of multiple genetic and non‐genetic factors and the genetic contribution is consequently often difficult to characterise. Recent advances suggest that subtle variation in the regulation of gene expression may contribute to complex human traits. In two reports,1,2 Cheung and colleagues scale up human genetics analysis to an impressive level in a genome‐wide search for the regulators of gene expression. They perform linkage analysis on expression profiles for over 3,500 genes and then employ the HapMap resource3 to take positive findings through to association studies at the genome‐wide level. This work gives new insights into the complexities of gene regulation and the plausibility of genome‐wide study design. BioEssays 28: 968–972, 2006. © 2006 Wiley Periodicals, Inc.
Prolactin in man: a tale of two promoters
Authors: Gerlo Sarah , Davis Julian R.E. , Mager Dixie L. , Kooijman Ron
Published: September 2006

The pituitary hormone prolactin (PRL) is best known for its role in the regulation of lactation. Recent evidence furthermore indicates PRL is required for normal reproduction in rodents. Here, we report on the insertion of two transposon‐like DNA sequences in the human prolactin gene, which together function as an alternative promoter directing extrapituitary PRL expression. Indeed, the transposable elements contain transcription factor binding sites that have been shown to mediate PRL transcription in human uterine decidualised endometrial cells and lymphocytes. We hypothesize that the transposon insertion event has resulted in divergent (pituitary versus extrapituitary) expression of prolactin in primates, and in differential actions of pituitary versus extrapituitary prolactin in lactation versus pregnancy respectively. Importantly, the TE insertion might provide a context for some of the conflicting results obtained in studies of PRL function in mice and man. BioEssays 28: 1051–1055, 2006. © 2006 Wiley Periodicals, Inc.
The rise, fall and renaissance of microsatellites in eukaryotic genomes
Authors: Buschiazzo Emmanuel , Gemmell Neil J.
Published: September 2006

Microsatellites are among the most versatile of genetic markers, being used in an impressive number of biological applications. However, the evolutionary dynamics of these markers remain a source of contention. Almost 20 years after the discovery of these ubiquitous simple sequences, new genomic data are clarifying our understanding of the structure, distribution and variability of microsatellites in genomes, especially for the eukaryotes. While these new data provide a great deal of descriptive information about the nature and abundance of microsatellite sequences within eukaryotic genomes, there have been few attempts to synthesise this information to develop a global concept of evolution. This review provides an up‐to‐date account of the mutational processes, biases and constraints believed to be involved in the evolution of microsatellites, particularly with respect to the creation and degeneration of microsatellites, which we assert may be broadly viewed as a life cycle. In addition, we identify areas of contention that require further research and propose some possible directions for future investigation. BioEssays 28: 1040–1050, 2006. © 2006 Wiley Periodicals, Inc.
Detrimental deletions: mitochondria, aging and Parkinson's disease
Authors: Biskup Saskia , Moore Darren J.
Published: September 2006

As individuals enter their 80s, they are inevitably confronted with the problem of neuronal loss in the brain. The incidence of the common movement disorder ‘mild parkinsonian signs’ (MPS) is approximately 50% over the age of 85 years. It has long been known that the loss of dopaminergic neurons in the substantia nigra pars compacta is a neuropathological hallmark of Parkinson's disease (PD). Recently, two papers1,2 present clear evidence for a high burden of mitochondrial DNA deletions within substantia nigra neurons in aged individuals and individuals with PD, pointing towards a common pathway inevitably leading to neuronal dysfunction and death. BioEssays 28: 963–967, 2006. © 2006 Wiley Periodicals, Inc.
Duplication, divergence and formation of novel protein topologies
Authors: Vogel Christine , Morea Veronica
Published: September 2006

The rearrangement or permutation of protein substructures is an important mode of divergence. Recent work1 explored one possible underlying mechanism called permutation‐by‐duplication, which produces special forms of motif rearrangements called circular permutations. Permutation‐by‐duplication, involving gene duplication, fusion and truncation, can produce fully functional intermediate proteins1 and thus represents a feasible mechanism of protein evolution. In spite of this, circular permutations are relatively rare and we discuss possible reasons for their existence. BioEssays 28: 973–978, 2006. © 2006 Wiley Periodicals, Inc.
Checkpoints and restriction points in bacteria and eukaryotic cells
Authors: Cooper Stephen
Published: September 2006

Bacterial checkpoints, analogous to those proposed to exist in eukaryotic cells, offer insights into the definition of a checkpoint. Examination of bacterial “checkpoint” or arrest phenomena illustrate problems with a too‐casual application of the checkpoint idea to eukaryotic phenomena. The question raised here is whether there are cellular processes that “check” whether a cellular process is completed. It is possible that many eukaryotic “checkpoints” may not have “checking” functions. Some of the ubiquitous checkpoint phenomena widely described may be merely the result of the inherent incompleteness of earlier events preventing the initiation of subsequent events. BioEssays 28: 1035–1039, 2006. © 2006 Wiley Periodicals, Inc.
Rho GTPase activity zones and transient contractile arrays
Authors: Bement William M. , Miller Ann L. , von Dassow George
Published: September 2006

The Rho GTPases—Rho, Rac and Cdc42—act as molecular switches, cycling between an active GTP‐bound state and an inactive GDP‐bound state, to regulate the actin cytoskeleton. It has recently become apparent that the Rho GTPases can be activated in subcellular zones that appear semi‐stable, yet are dynamically maintained. These Rho GTPase activity zones are associated with a variety of fundamental biological processes including symmetric and asymmetric cytokinesis and cellular wound repair. Here we review the basic features of Rho GTPase activity zones, suggest that these zones represent a fundamental signaling mechanism, and discuss the implications of zone properties from the perspective of both their function and how they are likely to be controlled. BioEssays 28: 983–993, 2006. © 2006 Wiley Periodicals, Inc.
Gas‐Phase Protonation and Deprotonation of Acrylonitrile Derivatives NCCHCHX (X=CH3, NH2, PH2, SiH3)
Authors: Luna Alberto , Mó Otilia , Yáñez Manuel , Gal Jean‐François , Maria P.‐C. , Guillemin Jean‐Claude
Published: September 2006

A combined experimental and theoretical study on the gas‐phase basicity and acidity of a series of cyanovinyl derivatives is presented. The gas‐phase basicities and acidities of (NCCHCHX, X=CH3, NH2) were obtained by means of Fourier transform ion cyclotron resonance (FT‐ICR) mass spectrometry techniques. The corresponding calculated values were obtained at the G3B3 level of theory. The effects of exchanging CH3 for SiH3, and NH2 for PH2, were analyzed at the same level of theory. For the neutral molecules, the Z isomer is always the dominant species under standard gas‐phase conditions at 298 K. The loss of the proton from the substituent X was found systematically to be much more favorable than deprotonation of the HCCH linking group. The corresponding isomeric E ion is much more stable than the Z ion, so that only the former should be found in the gas phase. The most significant structural changes upon deprotonation occur for the methyl and amino derivatives because, in both cases, deprotonation of X leads to a significant charge delocalization in the corresponding anion. Protonation takes place systematically at the cyano group, whereby the isomeric E ion is again more stable than the Z ion. Push–pull effects explain the preference of aminoacrylonitrile to be protonated at the cyano group, which also explains the high basicity of this derivative relative to other members of the analyzed series that present rather similar gas‐phase basicities, GB≈780 kJ mol−1, indicating that the different nature of the substituents has only a weak effect on the intrinsic basicity of the cyano group. The cyanovinyl derivatives have a significantly stronger gas‐phase acidity than that of the corresponding vinyl compounds CH2CHX. This acidity‐strengthening effect of the cyano group is attributed to the greater stabilization of the anion with respect to the corresponding neutral compound.
Ca2+– and Ba2+–Ligand Coordinated Unilamellar, Multilamellar, and Oligovesicular Vesicles
Authors: Song Aixin , Jia Xiangfeng , Teng Minmin , Hao Jingcheng
Published: September 2006

Ca2+‐ and Ba2+‐coordinated vesicle phases were prepared in mixed aqueous solutions of tetradecyldimethylamine oxide (C14DMAO) and calcium oleate (Ca(OA)2) or barium oleate (Ba(OA)2). At the right mixing ratios, metal–ligand coordination between Ca(OA)2 or Ba(OA)2 and C14DMAO results in the formation of molecular bilayers due to the reduction in area per head group. Ca2+ and Ba2+ tightly associate to the head groups of surfactants and in this system the bilayer membranes are not shielded by excess salts. The structures of the birefringent samples of the Ca(OA)2/C14DMAO/H2O and Ba(OA)2/C14DMAO/H2O systems were determined by freeze‐fracture transmission electron microscopy (FF‐TEM), small‐angle X‐ray scattering (SAXS), and rheological measurements to consist of unilamellar, multilamellar, and oligovesicular vesicles. The coordination between C14DMAO and Ba(OA)2 or Ca(OA)2 plays an important role in the formation of the vesicles, which was easily confirmed by studying the phase behavior of the KOA/C14DMAO/H2O system in which only the L1 phase forms, due to the absence of coordination between KOA and C14DMAO. A mechanism is proposed that accounts for the formation of these new metal–ligand coordinated vesicles.