bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractThe 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

AbstractPeptidylarginine 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

AbstractThe 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.
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

SummaryType 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

SummaryWe 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

SummaryWe 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

SummaryFabry 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

AbstractAimsTo 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.MethodsWe 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.ResultsThe 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.DiscussionsTo 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.
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

AbstractDefects 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.
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&lt;0.05) and 3.1-fold (P&lt;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&lt;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&lt;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&lt;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&lt;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.
Substrate and product specificities of cis-type undecaprenyl pyrophosphate synthase
Authors: CHEN Annie P.-C. , CHANG Sing-Yang , LIN Yu-Chung , SUN Yang-Sheng , CHEN Chao-Tsen , WANG Andrew H.-J. , LIANG Po-Huang 
Published: February 2005

UPPS (undecaprenyl pyrophosphate synthase) catalyses consecutive condensation reactions of FPP (farnesyl pyrophosphate) with eight isopentenyl pyrophosphates to generate C55 UPP, which serves as a lipid carrier for bacterial peptidoglycan biosynthesis. We reported the co-crystal structure of Escherichia coli UPPS in complex with FPP. Its phosphate head-group is bound to positively charged arginine residues and the hydrocarbon moiety interacts with hydrophobic amino acids including L85, L88 and F89, located on the α3 helix of UPPS. We now show that the monophosphate analogue of FPP binds UPPS with an eight times lower affinity (Kd=4.4 μM) compared with the pyrophosphate analogue, a result of a larger dissociation rate constant (koff=192 s−1). Farnesol (1 mM) lacking the pyrophosphate does not inhibit the UPPS reaction. GGPP (geranylgeranyl pyrophosphate) containing a larger C20 hydrocarbon tail is an equally good substrate (Km=0.3 μM and kcat=2.1 s−1) compared with FPP. The shorter C10 GPP (geranyl pyrophosphate) displays a 90-fold larger Km value (36.0±0.1 μM) but similar kcat value (1.7±0.1 s−1) compared with FPP. Replacement of L85, L88 or F89 with Ala increases FPP and GGPP Km values by the same amount, indicating that these amino acids are important for substrate binding, but do not determine substrate specificity. With GGPP as a substrate, UPPS still catalyses eight isopentenyl pyrophosphate condensation reactions to synthesize C60 product. Computer modelling suggests that the upper portion of the active-site tunnel, where cis double bonds of the product reside, may be critical for determining the final product chain length.
The effect of the farnesyl protein transferase inhibitor SCH66336 on isoprenylation and signalling by the prostacyclin receptor
Authors: O'MEARA Sarah J. , KINSELLA B. Therese 
Published: February 2005

Like Ras, farnesylation of the IP (prostacyclin receptor) is required for its efficient intracellular signalling, and hence the IP represents a potential target for inhibition by FTIs [FTase (farnesyl protein transferase) inhibitors]. Herein, the effect of SCH66336 on the isoprenylation and function of the human and mouse IPs overexpressed in human embryonic kidney 293 cells, and by the IP endogenously expressed in human erythroleukaemia cells, was investigated. SCH66336 yielded concentration-dependent decreases in IP-mediated cAMP generation (IC50 0.27–0.62 nM), [Ca2+]i mobilization (IC50 26.6–48.3 nM) and IP internalization, but had no effect on signalling by the non-isoprenylated β2 adrenergic receptor or β isoform of the TP (prostanoid thromboxane A2 receptor). Additionally, SCH66336 impaired IP-mediated crossdesensitization of TPα signalling (IC50 56.1 nM) and reduced farnesylation of the molecular chaperone protein HDJ-2 (IC50 3.1 nM). To establish whether farnesylation of the IP is inhibited and/or whether its ‘CaaX motif’ might undergo alternative geranylgeranylation in the presence of SCH66336, a series of chimaeric Ha (Harvey)-Ras fusions were generated by replacing its CaaX motif (-CVLS) with that of the IP (-CSLC) or, as controls, of Ki (Kirsten)-Ras 4B (-CVIM) or Rac 1 (-CVLL). Whereas SCH66336 had no effect on Ha-RasCVLL isoprenylation in vitro or in whole cells, it supported alternative geranylgeranylation of Ha-RasCVIM, but completely impaired isoprenylation of both Ha-RasCVLS and Ha-RasCSLC. These data confirm that the -CSLC motif of the IP is a direct target for inhibition by the FTI SCH66336, and in the presence of strong FTase inhibition, the IP does not undergo compensatory geranylgeranylation.