bluuebunny/crossref_metadata_2025 huggingface dataset:
Long‐range π‐type hydrogen bond in dimers CH2HF, CH2OH2O, and CH2ONH3
Authors: Li Rui Yan , Li Zhi Ru , Wu Di , Hao Xi Yun , Li Ru Jiao , Sun Chia Chung
Published: February 2005

Using four basis bets, (6‐311G(d,p), 6‐31+G(d,p), 6‐31++G(2d,2p), and 6‐311++G(3df,3pd), the optimized structures with all real frequencies were obtained at the MP2 level for the dimers CH2OHF, CH2OH2O, CH2ONH3, and CH2OCH4. The structures of CH2OHF, CH2OH2O, and CH2ONH3 are cycle‐shaped, which result from the larger bend of σ‐type hydrogen bonds. The bend of σ‐type H‐bond O…HY (YF, O, N) is illustrated and interpreted by an attractive interaction of a chemically intuitive π‐type hydrogen bond. The π‐type hydrogen bond is the interaction between one of the H atoms of CH2O and lone pair(s) on the F atom in HF, the O atom in H2O, or the N atom in NH3. In contrast with the above three dimers, for CH2OCH4, because there is not a π‐type hydrogen bond to bend its linear hydrogen bond, the structure of CH2OCH4 is noncyclic shaped. The interaction energy of hydrogen bonds and the π‐type H‐bond are calculated and discussed at the CCSD (T)/6‐311++G(3df,3pd) level. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Nonlinear optical constants of polymers from molecular hyperpolarizabilities of donor–acceptor molecules
Authors: Verwoerd W. S.
Published: February 2005

A mathematical analysis previously developed to solve the quadratic tensor equations that relate molecular hyperpolarizability and bulk medium nonlinear optical constants is applied to donor–acceptor polyene molecules. The focus is on mutual polarization of spatially organized collections of molecules, e.g., chromophore side chains in an optical polymer. The performance of the electrostatic model is first confirmed by comparison with MOPAC calculations of composite molecules containing a pair of chromophores, and then applied to linear polymer chains as well as lattices in two and three dimensions. An optimal chromophore packing density is determined to maximize the macroscopic susceptibilities of polymer materials of the type studied. This is lower than the density allowed by the structure of the polymer, because of the mutual depolarization of chromophores at high packing densities. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Characterisation of intact recombinant human erythropoietins applied in doping by means of planar gel electrophoretic techniques and matrix‐assisted laser desorption/ionisation linear time‐of‐flight mass spectrometry
Authors: Stübiger Gerald , Marchetti Martina , Nagano Marietta , Reichel Christian , Gmeiner Günter , Allmaier Günter
Published: February 2005

Our experiments show that it is possible to detect different types of recombinant human erythropoietins (rhEPOs), EPO‐α, EPO‐βand novel erythropoesis stimulating protein (NESP), based on exact molecular weight (MW) determination by matrix‐assisted laser desorption/ionisation mass spectrometry (MALDI‐MS) applying a high‐resolution time‐of‐flight (TOF) mass analyser in the linear mode. Detection limits for the highly purified, intact glycoproteins were achievable in the low fmol range (25–50 fmol) using a sample preparation method applying a hydrophobic sample support (DropStop®) as MALDI target surface. These results are very promising for the development of highly sensitive detection methods for a direct identification of rhEPO after enrichment from human body fluids. During our investigation we were able to differentiate EPO‐α, EPO‐βand NESP based on distinct molecular substructures at the protein level by specific enzymatic reactions. MW determination of the intact molecules by high resolving one‐dimensional sodium dodecyl sulfate /polyacrylamide gel electrophoresis (1D SDS‐PAGE) and isoform separation by planar isoelectric focusing (IEF) was compared with MALDI‐MS data. Migration differences between the rhEPOs were observed from gel electrophoresis, whereby MWs of 38 kDa in the case of EPO‐α/βand 49 kDa for NESP could be estimated. In contrast, an exact MW determination by MALDI‐MS based on internal calibration revealed average MWs of 29.8 ± 0.3 kDa for EPO‐α/βand 36.8 ± 0.4 kDa for NESP. IEF separation of the intact rhEPOs revealed the presence of four to eight distinct isoforms in EPO‐αand EPO‐β, while four isoforms, which appeared in the more acidic area of the gels, were detected by immunostaining in NESP. A direct detection of the different N‐ or O‐glycoform pattern from rhEPOs using MALDI‐MS was possible by de‐sialylation of the glycan structures and after de‐N‐glycosylation of the intact molecules. Thereby, the main glycoforms of EPO‐α, EPO‐βand NESP could be characterised based on their N‐glycan composition. A microheterogeneity of the molecules based on the degree of sialylation of the O‐glycan was observable directly from the de‐N‐glycosylated protein. Copyright © 2005 John Wiley & Sons, Ltd.
Rapid determination of acetone in human blood by derivatization with pentafluorobenzyl hydroxylamine followed by headspace liquid‐phase microextraction and gas chromatography/mass spectrometry
Authors: Deng Chunhui , Li Ning , Wang Xiaochuan , Zhang Xiangmin , Zeng Jia
Published: February 2005

In the current work, a simple, rapid, accurate and inexpensive method was developed for the determination of acetone in human blood. The proposed method is based on derivatization withO‐(2,3,4,5,6‐pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA), followed by headspace liquid‐phase microextraction (HS‐LPME) and gas chromatography/mass spectrometry (GC/MS). In the present method, acetone in blood samples was derivatized with PFBHA and acetone oxime formed in several seconds. The formed oxime was enriched by HS‐LPME using the organic solvent film (OSF) formed in a microsyringe barrel as extraction interface. Finally, the enriched oxime was analyzed by GC/MS in electron ionization (EI) mode. HS‐LPME parameters including solvent, syringe plunger withdrawal rate, sampling volume, and extraction cycle were optimized and the method reproducibility, linearity, recovery and detection limit were studied. The proposed method was applied to determination of acetone in diabetes blood and normal blood. It has been shown that derivatization with HS‐LPME and GC/MS is an alternative method for determination of the diabetes biomarker, acetone, in blood samples. Copyright © 2005 John Wiley & Sons, Ltd.
Rapid identification of siderophores by combined thin‐layer chromatography/matrix‐assisted laser desorption/ionization mass spectrometry
Authors: Hayen Heiko , Volmer Dietrich A.
Published: February 2005

The investigation of a combined thin‐layer chromatography/matrix‐assisted laser desorption/ionization mass spectrometry (TLC/MALDI‐MS) method for the analysis of siderophores from microbial samples is described. The investigated siderophores were enterobactin, ferrioxamine B, ferrichrome, ferrirhodin, rhodotorulic acid and coprogen. Solid‐phase extraction was employed to recover the siderophores from the microbial samples. After visualization of the spots via spraying with ferric chloride or chrome azurol sulfonate assay solution, the MALDI matrix was applied to the gel surface. Several TLC/MALDI experimental parameters were optimized, such as type and concentration of MALDI matrix, as well as the type and composition of solvent to facilitate analyte transport from the inside of the TLC gel to the surface. The impact of these parameters on sensitivity, precision and ion formation of the various siderophores was studied. The detection limits for the investigated siderophores were in the range 1–4 pmol. These values were about 4–24 times higher than the detection limits obtained directly from stainless steel MALDI targets. The differences were most likely due to incomplete transport of the ‘trapped’ analyte molecules from the deeper layers of the TLC gel to the surface and into the matrix layer. In addition, chromatographic band broadening spread the analyte further in TLC as compared with the steel plates, resulting in less analyte per surface area. The identification of the siderophores was aided by concurrently applying a Ga(III) nitrate solution to the TLC plate during the visualization step. The resulting formation of Ga(III) complexes lead to distinctive 69Ga/71Ga isotope patterns in the mass spectra. The versatility of the TLC/MALDI‐MS assay was demonstrated by using it to analyze siderophores in a Pseudomonas aeruginosa sample. An iron‐binding compound was identified in the sample, namely pyochelin (2‐(2‐o‐hydroxyphenyl‐2‐thiazolin‐4‐yl)‐3‐methylthiazolidine‐4‐carboxylic acid). Copyright © 2005 John Wiley & Sons, Ltd.
Determination of sites citrullinated by peptidylarginine deiminase using 18O stable isotope labeling and mass spectrometry
Authors: Kubota Kazuishi , Yoneyama‐Takazawa Tomoko , Ichikawa Kimihisa
Published: February 2005

Peptidylarginine deiminase (PADI) is an enzyme which catalyzes conversion of arginine residues into citrulline residues in proteins. Citrullination is known to be related to autoimmune diseases including rheumatoid arthritis. Previous work in this laboratory succeeded in identifying citrullinated sites of human fibrinogen by mass spectrometry, but discrimination between citrullination and deamidation of asparagines and glutamine required time‐consuming and labor‐intensive inspection of tandem mass spectra. In this work a stable isotope is utilized to improve on a previous method for the determination of citrullinated sites by mass spectrometry. Since an oxygen atom is incorporated into the citrulline residue from H2O in citrullination by PADI, peptides citrullinated in 50% HO would show a characteristic isotope distribution different from natural abundance, and thus determination of citrullinated sites is expected to be much easier. To verify the utility of this new method, the sites of citrullination of human fibrinogen by human PADI4 were investigated using 50% HO. Compared with the previous method, this new method identified citrullinated sites more easily and effectively, while both the determined citrullinated sites and protein sequence coverage were unaltered. Copyright © 2005 John Wiley & Sons, Ltd.
The use of turbulent flow chromatography and the isocratic focusing effect to achieve on‐line cleanup and concentration of neat biological samples for low‐level metabolite analysis
Authors: Herman J. L.
Published: February 2005

The use of turbulent flow chromatography in conjunction with column switching isocratic focusing was used to perform on‐line sample cleanup and concentration of neat rat plasma for the identification of low‐level metabolites. The concentration was achieved by focusing multiple injections, which were cleaned by a turbulent flow column, onto an analytical column prior to elution into the mass spectrometer. In addition, the first application of turbulent flow chromatography for on‐line sample cleanup of neat bile samples is reported. The on‐line cleanup and concentration method extracts and concentrates a sample 20‐fold in 1 h, and is completely automated. Copyright © 2005 John Wiley & Sons, Ltd.
Bone turnover in rats treated with 1,25-dihydroxyvitamin D3, 25-hydroxyvitamin D3 or 24,25-dihydroxyvitamin D3
Authors: Mortensen Berit M. , Gautvik Kaare M. , Gordeladze Jan O.
Published: February 2005

Female rats were given 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), 0.25 μg per 100 g body weight (bw), 25-hydroxyvitamin D3 (25(OH)D3), 1.7 μg/100 g bw or 24,25-dihydroxyvitamin D3 (24,25(OH)2D3) 1.7 μg/100 g bw, subcutaneously three times a week for 12 weeks. Traditional variables pertaining to calcium homeostasis and growth, i.e. blood and urine calcium (Ca) and phosphate (P), serum levels of vitamin D3 metabolites parathyroid hormone, (PTH), calcitonin (CT), prolactin (PRL) and growth hormone (GH) were measured every four weeks. This data pool was correlated with bone matrix turnover parameters, i.e. serum levels of alkaline phosphatase (ALP) and urinary hydroxyproline (u-HYP) excretion. After 12 weeks of treatment, 1,25(OH)2D3 significantly enhanced serum total and ionized Ca, urine Ca and urine P, and also diminished urine cAMP due to reduced renal function (creatinine clearance). However, 25(OH)D3 administration had no such impact. 24,25(OH)2D3 opposed the effect of 1,25(OH)2D3 after 12 weeks by significantly augmenting serum P and diminishing serum levels of total Ca and ionized Ca. Cross sectional group analyses showed that criculating levels of ALP were directly related with serum 1,25(OH)2D3 and inversely related to serum 24,25(OH)2D3 and CT. Total u-HYP and per cent non-dialysable HYP (ndHYP) were reciprocally and positively correlated with serum PRL, respectively. However, no such relations were observed with serum GH.

It appears that rats with elevated circulating levels of 1,25(OH)2D3 exhibit increased bone resorption, while augmented 24,25(OH)2D3 is associated with the opposite. Apparently, high bone turnover (i.e. reduced total urinary HYP and enhanced ndHYP) is associated with high serum PRL.
Effects of methylprednisolone on the energy metabolism of quiescent and conA-stimulated thymocytes of the rat
Authors: Buttgereit Frank , Brand Martin D. , Müller Marianne
Published: February 2005

The short-term effects of high concentrations of Methylprednisolone (MP) on the energy metabolism of quiescent and Concanavalin A-stimulated rat thymocytes were investigated in vitro. Concanavalin A (ConA) stimulated the respiration rate of quiescent thymocytes by 35%. Addition of more than 0.15 mg MP/107 cells to ConA-stimulated cells reversed this respiratory stimulation; in addition, higher concentrations of MP caused a similar progressive decrease in the rate of respiration of both quiescent and ConA-stimulated cells. Similarly, the stimulation of respiration by ConA was greatly reduced in MP-treated cells. MP addition lowered cytoplasmic [Ca2+] and, at high concentrations, abolished the ability of ConA to increase [Ca2+]. Thus MP both reverses and prevents the immediate stimulation of thymocytes by ConA.

In quiescent thymocytes, MP strongly inhibited that part of the oxygen consumption used to drive the cycle of Na+ influx across the plasma membrane and Na+ efflux on the Na+K+-ATPase, but did not inhibit oxygen consumption used to drive protein synthesis. In ConA-stimulated thymocytes MP had the same effects and also strongly inhibited oxygen consumption dependent on the cycle of Ca2+ influx across the plasma membrane and Ca2+ efflux on the Ca2+-ATPase, but had little effect on oxygen consumption used to drive RNA and DNA synthesis.

These results show that MP prevents cation cycling in thymocytes (either by preventing cation influx or by inhibiting cation pumps) and prevents mitogenic stimulation of the cells. The high MP concentration required and the speed of onset of the effect (lless than 30s) provide strong evidence that these effects of MP are not mediated by glucocorticoid receptors and subsequent activation of gene expression. They may be caused by direct effects of MP on the properties of the plasma membrane. These effects are considered to be, at least partially, responsible for the beneficial results that currently have been obtained using MP megadoses in various clinical situations.
Depolarization-independent net uptake of calcium into clonal insulin-releasing cells exposed to glucose
Authors: Gylfe Erik , Andersson Tommy , Rorsman Patrik , Abrahamsson Håkan , Arkhammar Per , Hellman Per , Hellman Bo , Oie Herbert K. , Gazdar Adi F.
Published: February 2005

Insulin release, net fluxes of Ca2+, and glucose metabolism were studied in a clonal cell line (RINmSF) established from a transplantable rat islet tumor. The insulin content amounted to only 0.03% of that of the total protein and decreased even further with subsequent passages. The insulin secretion was as high as 10 to 20% of the total hormone content per hour. Insulin release was stimulated by K+ depolarization but not by exposure to glucose. In contrast to this secretory pattern, glucose but not K+ stimulated the net uptake of Ca2+ at micromolar concentrations of the ion. The glucose effect was not mimicked by 20 mM 3-O-methylglucose. It was as pronounced at 1 mM as at 20 mM of the sugar and corresponded to an uptake of 119 fmol cm−2 s−1. Glucose metabolism was typical for tumor cells with a high glycolytic flux and an oxidationtoutilization ratio as low as 0.05–0.15. Maximal oxidative degradation was attained already at l mM. This concentration was also equivalent to the Km for glucose utilization, indicating a substantial left-hand shift of the normal dose-response curve. It is suggested that glucose induces a depolarizationindependent net uptake of Ca2+ by favouring intracellular buffering of the cation.
Carbaryl-induced elevation of corticosterone level and cholinergic mechanism
Authors: Ray S. K. , Poddar M. K.
Published: February 2005

Administration of a single dose (200 mg/kg, p.o.) of carbaryl to rats produced a significant rise in adrenal and plasma corticosterone levels and an increase of tyrosine α-ketoglutarate transaminase activity in the liver cytosot. Synaptosomal acetylcholinesterase activity of the hypothalamic and the striatal regions of rat brain was decreased by carbaryl treatment under similar conditions. Pretreatment (0.5 h) with atropine sulphate (10 mg/kg, i.p.) failed to counteract the carbaryl-induced elevation of adrenal and plasma corticosterone levels and hence the liver tyrosine α-ketoglutarate transaminase activity. Present results suggest that the carbaryl-induced rise in the corticosterone level in the adrenal gland and plasma is not due to a cholinergic mechanism.
Dye affinity chromatography of ricin subunits
Authors: Sperti Simonetta , Montanaro Lucio , Rambelli Fioretta
Published: February 2005

A rapid and simple method for the isolation of the two chains of ricin is described. The method involves two chromatographic runs, the first on blue-Sepharose and the second on blue dextran-Sepharose. It is moreover shown that the A chain of ricin, but not the B chain, binds to poly(U)-Sepharose.
Multiwell cap assay: A simple objective method for the assessment of leukocyte locomotionin vitro
Authors: Evans Anne M. , David Chambers J. , Hobbs John R.
Published: February 2005

A simple method for evaluating leukocyte locomotion in vitro has been developed and validated for several chemoattractants. The multiwell cap assay (MWCA) comprises chambers constructed from readily available disposable plastics and is quickly assembled, permitting large experimental protocols. Leukocytes which have migrated through a micropore filter are recovered and counted electronically yielding a precise, objective result. Coefficients of variation are approximately 6%.
Discrimination between M2 and M4 antimitochondrial antibodies in primary biliary cirrhosis
Authors: Ghadiminejad Iraj , Baum Harold
Published: February 2005

10 sera were studied from patients with primary biliary cirrhosis (PBC), that were anomalous in their reactivity against mitochondrial antigens as detected by Western blotting. They had low reactivity against the major, M2 reactive antigen (Mr for beef heart mitochondria, 74 Kd) but reacted against an antigen of Mr 52 Kd (species independent) which was apparently inaccessible in submitochondrial particles (SMP) on ELISA and which was not present in chloroform-released ATPase preparations. In all respects this differed from the characteristics of the M2 antigens and it is concluded that these sera are detecting predominantly the M4-reactive antigen.
Functional dedifferentiation of parathyroid cells results both from a defective regulation and action of cytoplasmic Ca2+
Authors: Nygren Peter
Published: February 2005

Monolayer culture of bovine parathyroid cells for 24 hours resulted in a right-shift of the dose-effect relationships for Ca2+-inhibition of parathyroid hormone (PTH) release and the dependence of the cytoplasmic Ca2+ concentration (Ca2+) on extracellular Ca2+ as well as in a less suppressible hormone release. After 4 days of culture, hormone secretion was almost non-suppressible and Cai2+ increased poorly in response to a rise in extracelluiar Ca2+. Ionomycin, a Ca2+ ionophore, raised Cai2+, but there was only a small inhibition of PTH release and the correlation between Cai2+ and secretion was weak. A deteriorated Cai2+ regulation and a decreased inhibitory action of cytoplasmic Ca2+ on PTH release were also found in ceils from human parathyroid adenomas. Functional dedifferentiation of the parathyroid cell thus results from both defective regulation and action of cytoplasmic Ca2+.
The activity of the pyruvate dehydrogenase complex in heart muscle in the previously obese mouse model
Authors: Steinbeck Kate , Caterson Ian D. , Turtle John R.
Published: February 2005

Obese gold thioglucose injected mice were reduced to lean control weight by food restriction. When pair fed with lean controls these animals then gained weight (were metabolically more efficient). Serum glucose was also elevated in this group (14.5±0.4 (14) vs 12.1±0.3 mmol/L, p<0.001). If previously obese animals were weight maintained with lean controls (by mild food restriction), serum glucose remained at control levels. The activity of the pyruvate dehydrogenase complex in heart muscle was decreased in both obese and pair fed previously obese, whilst it was similar to that of lean controls in the weight maintained previously obese and in obese mice actually dieted. In all obese and previously obese animals serum insulin was elevated. In hearts from control animals subjected to mild food restriction the pyruvate dehydrogenase complex was activated (11.53±1.80 (5) vs 3.34±0.62 (9) U/g dry weight), despite a reduced serum insulin level (42±2 vs 74±10 μU/ml, p<0.01). These diverse changes in the proportion of the pyruvate dehydrogenase complex in the active form and insulin levels argue for a persistent alteration in the sensitivity of the pyruvate dehydrogenase complex to insulin in obesity, as well as indicating that glucose metabolism in obese animals is altered by both body weight and diet amount.
Effect of ligation of common bile duct on somatostatin levels and binding in cytosol of rabbit duodenal mucosa
Authors: Guijarro L. G. , Prieto J. C. , Arilla E.
Published: February 2005

Rabbits with ligation of the common bile duct, of one and three weeks duration, showed a significant increase of somatostatin content in duodenal mucosa and plasma as compared with control animals. The increase of mucosal somatostatin was associated with a decrease in the binding capacity of both high- and low-affinity binding sites without changes in the affinity values in cytosol of duodenal mucosa. These findings suggest that the number of somatostatin binding sites is inversely related to local levels of the peptide and support the hypothesis of somatostatin regulating its own binding sites.
Plasma chitotriosidase and CCL18: Early biochemical surrogate markers in type B Niemann‐Pick disease
Authors: Brinkman J. , Wijburg F. A. , Hollak C. E. , Groener J. E. , Verhoek M. , Scheij S. , Aten J. , Boot R. G. , Aerts J. M.
Published: February 2005

Type B Niemann‐Pick disease (NPD) is a nonneuronopathic lysosomal storage disorder which is characterized by accumulation of sphingomyelin‐laden macrophages. The availability of plasma markers for storage cells may be of great value in facilitating therapeutic decisions. Given the similarity of the storage cells in NPD and Gaucher disease, we studied Gaucher plasma markers (chitotriosidase and CCL18) in two siblings homozygous for the R228C mutation in acid sphingomyelinase (ASM) and a type B course of NPD. The older sibling, first examined at the age of 9 months, showed marked hepatosplenomegaly and pulmonary involvement. The younger sibling has mild asymptomatic hepatosplenomgaly at the age of 5 months. Analysis of plasma specimens revealed markedly increased levels of chitotriosidase and CCL18 in the older sibling. In the younger child also, plasma chitotriosidase and CCL18 were clearly elevated above normal values almost immediately after birth and rapidly increased further. Histochemistry confirmed production of CCL18 by foam cells. In conclusion, plasma chitotriosidase and CCL18 may also serve as markers for the formation of pathological lipid‐laden macrophages in type B NPD, in analogy to Gaucher disease. The availability of sensitive plasma surrogate markers may be of great value for monitoring the efficacy of enzyme supplementation therapy that is currently being developed.
Two Japanese brothers with hereditary γ‐glutamyl transpeptidase deficiency
Authors: Iida M. , Yasuhara T. , Mochizuki H. , Takakura H. , Yanagisawa T. , Kubo H.
Published: February 2005

We report on two Japanese brothers with hereditary deficiency in γ‐glutamyl transpeptidase. The propositus was 48 years old when he first visited our medical center and had a 51‐year‐old brother. The brothers were both tall and slender and had long limbs; the younger was diagnosed as having Marfan syndrome. Both patients both showed a tendency to retarded mental development. γ‐Glutamyltranspeptidase activity was below the detection limit of 1 IU/L in both patients. Glutathionaemia and glutathionuria were evident in both brothers. The analyses of sulphydryl compounds in the plasma (and serum for certain test items) and urine indicated high concentrations of glutathione, γ‐glutamylcysteine, cysteine and cysteinylglycine. Urine amino acid analysis on an automatic analyser showed a slightly increased excretion of cystine and a large peak in the citrulline position due, at least in part, to thio‐compounds.
Successful treatment of severe cardiomyopathy with NTBC in a child with tyrosinaemia type I
Authors: André N. , Roquelaure B. , Jubin V. , Ovaert C.
Published: February 2005

We report the case of a child who developed severe obstructive hypertrophic cardiomyopathy revealing hereditary tyrosinaemia type I, who was successfully treated with NTBC. The mechanisms underlying the association are discussed.
Measurement of urinary CDH and CTH by tandem mass spectrometry in patients hemizygous and heterozygous for Fabry disease
Authors: Mills K. , Morris P. , Lee P. , Vellodi A. , Waldek S. , Young E. , Winchester B.
Published: February 2005

Fabry disease is an X‐linked disorder of glycosphingolipid metabolism resulting from a deficiency of the lysosomal enzyme α‐galactosidase A. This deficiency leads to the progressive accumulation, in lysosomes of visceral tissues and in body fluids of hemizygotes, of the glycosphingolipids globotriaosylceramide (CTH, Gb3 or GL‐3) and galabiosylceramide (CDH) and to a lesser extent the blood group AB and B related glycolipids. Elevated levels of the glycosphingolipids are found in the urine of hemizygous males with the classic phenotype, but it is not known whether all symptomatic or asymptomatic heterozygotes have elevated levels. We have therefore measured CTH and CDH quantitatively in a multiplex assay using tandem mass spectrometry in urine from a large cohort (44) of genetically proven or obligate heterozygotes including four with the N215S mutation, from classic hemizygotes (28), from cardiac variant hemizygotes with the N215S mutation (6) and from normal controls. The levels of CTH and CDH were related to both creatinine and sphingomyelin. Urinary CTH was elevated in all 28 classic hemizygotes but only in 4/6 of the cardiac variants. The level was within or just above the normal reference range in the four individuals heterozygous for the N215S mutation but was elevated in 38/40 of the other heterozygotes. Similar results were obtained for CDH, except that only 34/40 heterozygotes had an elevated level. The level of CDH was not elevated in the four heterozygotes and 4/6 of the hemizygotes for the N215S mutation. Combining the levels of CTH and CDH did not improve the discrimination of heterozygotes from controls. The ratio of CDH to CTH was higher in heterozygotes than in hemizygotes. Measurement of urinary CTH gave the best discrimination of heterozygotes from controls.
Effects of internal displacement and resettlement on the mental health of Turkish children and adolescents
Authors: Erol Neşe , Şimşek Zeynep , Öner Özgür , Munir Kerim
Published: February 2005

Aims

To evaluate the effects of internal displacement and resettlement within Turkey on the emotional and behavioral profile of children, age 5–18 after controlling for possible confounding and demographic variables.

Methods

We conducted a national population survey using a self-weighted, equal probability sample. We compared the CBCL, TRF and YSR responses regarding children with (n= 1644) and without (n= 1855) experience of internal displacement. We examined the effects of gender, age, paternal employment, resettlement, urban residence and physical illness.

Results

The children and adolescents with internal displacement had significantly higher internalizing, externalizing and total problem scores on the CBCL and YSR, and higher internalizing scores on the TRF. The effect of displacement was related to higher internalizing problems when factors like physical illness, child age, child gender and urban residence were accounted. The overall effect was small explaining only 0.1–1.5% of the total variance by parent reports, and not evident by teacher reports.

Discussions

To our knowledge the present study is the first to examine Turkish children and adolescents with and without experience of internal displacement. The results are consistent with previous immigration studies: child age, gender, presence of physical illness and urban residence were more important predictors of internalization and externalization problem scores irrespective of informant source.
Fractal nature of chromatin organization in interphase chicken erythrocyte nuclei: DNA structure exhibits biphasic fractal properties
Authors: Lebedev D.V. , Filatov M.V. , Kuklin A.I. , Islamov A.Kh. , Kentzinger E. , Pantina R. , Toperverg B.P. , Isaev-Ivanov V.V.
Published: February 2005

Arrangement of chromatin in intact chicken erythrocyte nuclei was investigated by small angle neutron scattering. The scattering spectra have revealed that on the scales between 15 nm and 1.5 μm the interior of the nucleus exhibited properties of a mass fractal. The fractal dimension of the protein component of cell nucleus held constant at approximately 2.5, while the DNA organization was biphasic, with the fractal dimension slightly higher than 2 on the scales smaller than 300 nm and approaching 3 on the larger scales.
Human receptor Smoothened, a mediator of Hedgehog signalling, expressed in its native conformation in yeast
Authors: De Rivoyre Matthieu , Bonino Frédéric , Ruel Laurent , Bidet Michel , Thérond Pascal , Mus-Veteau Isabelle
Published: February 2005

Though the role of Hedgehog (Hh) signalling in patterning and differentiation during development is well established, the underlying signal transduction mechanisms remain obscure. This is the first report on the overexpression of the human Hh signalling receptor Smoothened (hSmo) in Saccharomyces cerevisiae and Pichia pastoris. We show that hSmo is expressed in both types of yeast in its native conformational state. The first purification presented here will allow the characterisation of hSmo expressed in yeast, and the scale‐up of hSmo production enabling structural studies to develop new therapeutic approaches against tumors and neurodegenerative diseases induced by Hh signalling dysfunction.
Cell‐cycle‐dependent regulation of the human and mouse Tome‐1 promoters
Authors: Yoshida Kenichi
Published: February 2005

Tome‐1, which refers to a trigger of mitotic entry 1, mediates the destruction of the mitosis‐inhibitory kinase, Wee1, via the E3 ligase, SCF. In turn, Tome‐1 itself is targeted for degradation by APC in the G1 phase of the cell cycle. In the present study, we analyzed the human and mouse Tome‐1 promoter regions. Using synchronized cultures of NIH3T3 cells transfected with Tome‐1 promoter/luciferase constructs, we showed that the promoter activity of Tome‐1 is activated at the G2/M phase. Using various Tome‐1 promoter/luciferase constructs, we showed that the CCAAT box located upstream of the transcription initiation site is important for the basal promoter activity. We identified a repressor element (cell‐cycle‐dependent element/cell cycle gene homology region) in the vicinity of the transcription start site, and mutations within this element diminished the cell‐cycle‐dependent transcriptional regulation of Tome‐1.
Fibrillogenesis of apomyoglobin facilitated by aggregation sequence of yeast Sup35 in various regions
Authors: He Yingbo , Tang Huadong , Yi Zhiwei , Zhou Hao , Luo Yongzhang
Published: February 2005

To examine the effect of aggregation sequence QGGYQQQYNP from yeast Sup35 on fibril formation of sperm whale apomyoglobin (apoMb), we constructed several mutants via substitution. Urea‐induced unfolding of apoMb confirms that the substitution of the aggregation sequence does not significantly affect the stability of the mutants compared to wild type (WT) at pH 4.2. Under this condition, however, despite the difference in rate most apoMb mutants form fibrils more readily than WT with distinct morphology. These results suggest that the aggregation sequence facilitates fibril assembly of apoMb at acidic pH in vitro and this facilitation depends on the regions replaced.
Inducible double‐stranded RNA expression activates reversible transcript turnover and stable translational suppression of a target gene in transgenic tobacco
Authors: Lo Clive , Wang Nai , Lam Eric
Published: February 2005

A binary vector amenable to high‐throughput cloning was constructed for ethanol‐inducible expression of double‐stranded RNA (dsRNA) in plants. Silencing of a transgene encoding β‐glucuronidase (GUS) was then examined at RNA and protein levels in tobacco. Transient gene silencing could be effectively achieved in plants with higher expression levels of alcR (the ethanol sensor) after single application of 1% ethanol (v/v) through root drenching. GUS activities showed more dramatic pattern of loss and recovery in young leaves than in older leaves. Repeated ethanol treatment resulted in extended gene suppression and increased loss of GUS activities. Interestingly, recovery of GUS transcript level is dramatically earlier than that of GUS protein levels as measured by enzyme assays. These observations indicate that dsRNA‐mediated gene silencing may occur through more stable translational inhibition in addition to reversible targeted RNA degradation.
Robustness, evolvability, and neutrality
Authors: Wagner Andreas
Published: February 2005

Biological systems, from macromolecules to whole organisms, are robust if they continue to function, survive, or reproduce when faced with mutations, environmental change, and internal noise. I focus here on biological systems that are robust to mutations and ask whether such systems are more or less evolvable, in the sense that they can acquire novel properties. The more robust a system is, the more mutations in it are neutral, that is, without phenotypic effect. I argue here that such neutral change – and thus robustness – can be a key to future evolutionary innovation, if one accepts that neutrality is not an essential feature of a mutation. That is, a once neutral mutation may cause phenotypic effects in a changed environment or genetic background. I argue that most, if not all, neutral mutations are of this sort, and that the essentialist notion of neutrality should be abandoned. This perspective reconciles two opposing views on the forces dominating organismal evolution, natural selection and random drift: neutral mutations occur and are especially abundant in robust systems, but they do not remain neutral indefinitely, and eventually become visible to natural selection, where some of them lead to evolutionary innovations.
From protein networks to biological systems
Authors: Uetz Peter , Finley Russell L.
Published: February 2005

A system‐level understanding of any biological process requires a map of the relationships among the various molecules involved. Technologies to detect and predict protein interactions have begun to produce very large maps of protein interactions, some including most of an organism's proteins. These maps can be used to study how proteins work together to form molecular machines and regulatory pathways. They also provide a framework for constructing predictive models of how information and energy flow through biological networks. In many respects, protein interaction maps are an entrée into systems biology.
Prolonged‐fresh preservation of intact whole canine femoral condyles for the potential use as osteochondral allografts
Authors: Williams James M. , Virdi Amarjit S. , Pylawka Tamara K. , Edwards Ryland B. , Markel Mark D. , Cole Brian J.
Published: February 2005

Defects in articular cartilage are often repaired with fresh osteochondral grafts. While fresh allografts provide viable chondrocytes, logistic limitations require surgical implantation within seven days of graft harvest. Here, we provide information on cold preservation of whole intact osteochondral materials that retains cartilage cell viability and function, and histologic and biochemical integrity for 28 days. Canine femoral condyles were obtained and stored at 4°C for 14, 21 or 28 days. At the end of the storage period, cartilage was assessed for cell viability, 35S uptake, proteoglycan content and histologic parameters. The most noticeable histologic change was reduced Safranin‐O near the cartilage surface with 14 days of cold preservation, but had recovered with 21 and 28 days. Cartilage thicknesses did not vary significantly. Cell viability was > 95% at 14 days, 75–98% at 21 days and reduced to 65–90% at 28 days. Cell function measures showed that the level of 35SO4 incorporation was suppressed in samples stored at 4°C. However, no significant differences were seen among groups at 14.21 or 28 days of cold preservation. This data has implications for tissue banking protocols for osteochondral allograft material obtained for transplantation suggesting that cold preserved allograft material be implanted within 28 days. © 2004 Published by Elsevier Ltd. on behalf of Orthopaedic Research Society.
Cobalt and nickel in the Peru upwelling region: A major flux of labile cobalt utilized as a micronutrient
Authors: Saito Mak A. , Moffett James W. , DiTullio Giacomo R.
Published: February 2005

The geochemistry of cobalt in the Peru upwelling region is dominated by its importance as a micronutrient. A large and previously undocumented flux of labile cobalt behaved as a micronutrient with correlations with major nutrients (nitrate, phosphate; r2 = 0.90, 0.96) until depleted to ≤50 pM of strongly complexed cobalt. Co:P utilization ratios were an order of magnitude higher than in the North Pacific, comparable to utilization rates of zinc in other oceanic regions. Cobalt speciation measurements showed that available cobalt decreased over 4 orders of magnitude in this region, with shifts in phytoplankton assemblages occurring at transitions between labile and nonlabile cobalt. Only small changes in total dissolved nickel were observed, and nickel was present in a labile chemical form throughout the region. In the Peru upwelling region, cobalt uptake was highest at the surface and decreased with depth, suggesting phytoplankton uptake was a more important removal mechanism than co‐oxidation with microbial manganese oxidation. These findings show the importance of cobalt as a micronutrient and that cobalt scarcity and speciation may be important in influencing phytoplankton species composition in this economically important environment.
Paleostress evolution of the northern Andes (Eastern Cordillera of Colombia): Implications on plate kinematics of the South Caribbean region
Authors: Cortés Martín , Angelier Jacques , Colletta Bernard
Published: February 2005

New tectonic field data and paleostress determinations in the Eastern Cordillera of Colombia enable us to identify stress regimes that prevailed in the northern Andes since Late Cretaceous times until present day. These regimes were characterized by an E‐W to WSW‐ENE active contraction from Late Cretaceous to late Paleocene. This direction subsequently changed to NW‐SE and finally became WNW‐ESE during the Andean tectonic phase. The characteristics and relative chronology of these regimes were deduced from field structures and stratigraphic criteria, using stress inversion of fault slip data sets. To evaluate our model, we used the rotation poles of the South America, Caribbean and Nazca plates relative to North America, and paleogeographic reconstructions of the Caribbean region to derive a kinematic model of the northern Andes. Assuming a general correspondence between the regional convergence directions and the regional compression, we built a theoretical model of the regional stress regimes based on kinematics of the northwestern South America since Late Cretaceous times. This model reveals a major variation at the end of the Paleocene when relative divergence shifted to convergence between the Americas. This is in agreement with our tectonic model based on independent tectonic field data inversion in the Eastern Cordillera. This regional kinematic and tectonic change, which affected the Caribbean at the end of the Paleocene, was responsible for, and consistent with, the major change in stress patterns and structural style in the Eastern Cordillera. It is also coeval with the development of a major regional unconformity in Colombia.
Soil temperature in Canada during the twentieth century: Complex responses to atmospheric climate change
Authors: Zhang Yu , Chen Wenjun , Smith Sharon L. , Riseborough Daniel W. , Cihlar Josef
Published: February 2005

Most climate records and climate change scenarios projected by general circulation models are for atmospheric conditions. However, permafrost distribution as well as ecological and biogeochemical processes at high latitudes is mainly controlled by soil thermal conditions, which may be affected by atmospheric climate change. In this paper, the changes in soil temperature during the twentieth century in Canada were simulated at 0.5° latitude/longitude spatial resolution using a process‐based model. The results show that the mean annual soil temperature differed from the mean annual air temperature by −2° to 7°C, with a national average of 2.5°C. Soil temperature generally responded to the forcing of air temperature but in complex ways. The changes in annual mean soil temperature during the twentieth century differed from that of air temperature by −3° to 3°C from place to place, and the difference was more significant in winter and spring. On average, for the whole of Canada the annual mean soil temperature at 20 cm depth increased by 0.6°C, while the annual mean air temperature increased by 1.0°C. Three mechanisms were investigated to explain this differentiation: air temperature change, which altered the thickness and duration of snow cover, thereby altering the response of soil temperature; seasonal differences in changes of air temperature; and changes in precipitation. The first two mechanisms generally buffer the response of soil temperature to changes in air temperature, while the effect of precipitation is significant and varies with time and space. This complex response of soil temperature to changes in air temperature and precipitation would have significant implications for the impacts of climate change.
Field monoterpene emission of Mediterranean oak (Quercus ilex) in the central Iberian Peninsula measured by enclosure and micrometeorological techniques: Observation of drought stress effect
Authors: Plaza J. , Núñez L. , Pujadas M. , Pérez‐Pastor R. , Bermejo V. , García‐Alonso S. , Elvira S.
Published: February 2005

An experimental characterization of biogenic emission from Quercus ilex ssp. rotundifolia in a forest near Madrid, Spain, was carried out in the early autumn of the years 2000–2003. A dynamic branch enclosure technique was implemented to determine the monoterpene emission rates of this evergreen oak species during the 2000 and 2001 campaigns. Major compounds emitted during both measurement periods were limonene, α‐pinene, β‐pinene, sabinene, and myrcene. In the 2000 field campaign the light‐ and temperature‐dependent model of Guenther et al. [1993] did not fit the data due to drastic reductions of emission rates (and leaf gas exchange related parameters) observed at high air temperature and low air humidity (high water vapor pressure deficit). This plant physiological activity depletion and the subsequent emission reduction were attributed to severe water soil deficit conditions, as precipitation was very scarce during the growing season. In contrast, during the 2001 field campaign, neither emission nor physiological activity showed strong decreases in hot days. A good fit of experimental data to Guenther model was achieved in this field campaign (r2 = 0.90), and linear regression gave a standard emission factor (ES) of 14.0 μg gdw−1 h−1 (gdw is grams dry weight). Soil moisture was presumably higher than during the 2000 campaign due to recent rain events. With the purpose of documenting the drought stress effect at canopy level, monoterpene oak fluxes were measured by the modified Bowen ratio micrometeorological technique throughout the 2001 field campaign and in the late summer of 2002 and 2003. The measured emission by both techniques showed a reasonably good correlation, although micrometeorological fluxes were, in general, lower than upscaled branch emission rates. According to Guenther's parameterization, standard emission fluxes (FS) of 0.30 μg m−2 s−1 (r2 = 0.61) and 0.28 μg m−2 s−1 (r2 = 0.67) were derived for the 2001 and 2002 field campaigns, respectively. However, measured fluxes in September 2003 at high ambient temperature were much lower than those of the previous years. Moreover, from the CLCT range in which emission in this field campaign could be fitted to a linear behavior, the FS value obtained was 50% lower than the 2001 and 2002 values. Water xylem potential measurements indicated the existence of drought conditions during the 2003 campaign and unstressed water conditions during the 2002 campaign.
On the mechanism of the increase in cardiolipin biosynthesis and resynthesis in hepatocytes during rat liver regeneration
Authors: WEBSTER Jennifer , JIANG Jenny Y. , LU Biao , XU Fred Y. , TAYLOR William A. , MYMIN Mathew , ZHANG Manna , MINUK Gerald Y. , HATCH Grant M.
Published: February 2005

CL (cardiolipin) is a major mitochondrial membrane phospholipid important for the regulation of mitochondrial function. We examined CL de novo biosynthesis and its resynthesis in isolated rat liver hepatocytes prepared 48 h subsequent to two-thirds PHx (partial hepatectomy). The pool size of CL and its de novo biosynthesis from [1,3-3H]glycerol were increased 3.3-fold (P<0.05) and 3.1-fold (P<0.05) respectively in hepatocytes prepared from PHx rats compared with sham-operated controls. The reason for the increased CL biosynthesis was a 65% increase (P<0.05) in enzymic activity in PGP-S (phosphatidylglycerolphosphate synthase), a key enzyme in de novo CL biosynthesis. The increase in PGP-S activity was due to a 3-fold increase (P<0.05) of hepatic PGP-S mRNA expression. The increase in de novo CL biosynthesis and pool size corresponded to a 2.3-fold increase (P<0.05) in the amount of [1-14C]linoleic acid incorporated into CL of hepatocytes prepared from PHx rats compared with sham-operated controls, indicating an increase in CL resynthesis. The activity of MLCL-AT (monolysocardiolipin acyltransferase), a rate-limiting enzyme of CL resynthesis, was increased by 43% (P<0.05) in hepatocytes prepared from PHx rats compared with sham-operated controls; this result would explain the increase in [1-14C]linoleic acid incorporation into CL. The increase in MLCL-AT activity was due to an increase in hepatic MLCL-AT protein expression. The results show that CL de novo biosynthesis and its resynthesis are increased during liver regeneration.