bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pseudo‐glutarylcarnitinaemia in medium‐chain acyl‐CoA dehydrogenase deficiency detected by tandem mass spectrometry newborn screening
Authors: Napolitano N. , Wiley V. , Pitt J. J. 
Published: August 2004

AbstractSummary: As well as characteristic increases in C8 carnitine, dried blood spot samples from 11 newborns with medium‐chain acyl‐CoA dehydrogenase deficiency detected by tandem mass spectrometry screening using butyl esters showed apparent increases in glutarylcarnitine (m/z 388 signals). In four of the newborns in which it was measured, apparent increases in malonylcarnitine (m/z 360) were also detected. It was shown that the apparent increases were caused by interfering acylcarnitines, putatively identified as hydroxyoctanoylcarnitine and hydroxydecanoylcarnitine, respectively, using alternative derivatives for tandem mass spectrometry. Levels of the two abnormal carnitines correlated with C8 carnitine levels and normalized with repeat testing in 10 cases. These results indicated that the abnormal carnitines were significantly elevated only during periods of increased fatty acid catabolism, as may occur in the immediate postnatal period.
GTP‐cyclohydrolase I gene mutations in patients with autosomal dominant and recessive GTP‐CH1 deficiency: Identification and functional characterization of four novel mutations
Authors: Garavaglia B. , Invernizzi F. , Carbone M. L. Agostoni , Viscardi V. , Saracino F. , Ghezzi D. , Zeviani M. , Zorzi G. , Nardocci N. 
Published: August 2004

AbstractSummary: GTP‐cyclohydrolase I (GTP‐CH1, EC 3.5.4.16) is encoded by the GCH1 gene. Mutations in the GCH1 gene cause both dopa‐responsive dystonia (McKusick 128230) and recessive GTP‐CH1 deficiency (McKusick 600225). The exact molecular mechanism resulting in decreased GTP‐CH1 activity in the patients is still obscure. We report the clinical features and molecular and functional study of the GCH1 gene in eight Italian patients affected by dominant and recessive GTP‐CH1 deficiency. All the studied patients had mutations in the GCH1 gene. Three missense mutations (V205G, K224R, P199A), a frameshift mutation (ΔG693), and a splice‐site mutation (ivs5 + 1g > c) were found. Except for K224R these are all novel mutations. To analyse the defect caused by the novel mutations, an in vivo functional assay in a Saccharomyces cerevisiae strain lacking the endogenous gene encoding GTP‐CH1 (FOL2) was performed. Complementation analysis showed that the ΔG693 and V205G mutations abolish the enzymatic function, while the P199A mutation causes a conditional defect. In conclusion, the clinical phenotypes displayed by our patients confirm the wide clinical spectrum of the disease and further support the lack of correlation between a given mutation and a clinical phenotype. Complementation analysis in yeast is a useful tool for confirming the pathogenetic effect of GCH1 mutations.
Efficiency of long‐term tetrahydrobiopterin monotherapy in phenylketonuria
Authors: Steinfeld R. , Kohlschütter A. , Ullrich K. , Lukacs Z. 
Published: August 2004

AbstractSummary: Phenylketonuria, an inborn error of phenylalanine metabolism, occurs with a frequency of about 1 in 10 000 births and is treated with a strict dietary regimen. Recently, some patients with PKU have been found to show increased tolerance towards phenylalanine intake while receiving tetrahydrobiopterin (BH4) supplementation. We have treated two infants with BH4‐responsive PKU with BH4 for more than 2 years. No additional dietary control was required to maintain blood phenylalanine concentrations in the desired range. Both children have shown normal development. Generally, our results suggest that BH4 treatment might be an option for some patients with mild PKU, as it frees them from dietary restrictions and thus improves their quality of life.
Pseudo‐lysosomal storage disease caused by EMLA cream
Authors: Vallance H. , Chaba T. , Clarke L. , Taylor G. 
Published: August 2004

AbstractSummary: Prilocaine–lidocaine emulsion (EMLA cream) is a topical anaesthetic commonly used prior to diagnostic and therapeutic procedures. While undergoing clinical investigation for the suspicion of a metabolic disorder, a series of children underwent skin biopsy with EMLA cream pretreatment. In each case, the pathologist identified ultrastructural features consistent with a lysosomal storage disorder, yet the clinical features were not consistent with the pathological findings. Ultrastructural artefact was suspected, resulting from the use of the EMLA cream. All patients underwent repeat skin biopsy without EMLA cream. Biopsies were reviewed by two pathologists blinded to the previous biopsy findings. Electron microscopy repeated without the use of EMLA cream was normal. It is concluded that the use of EMLA cream causes ultrastructural artefact and should be avoided prior to skin biopsy for electron microscopy.
The role of oxidative damage in the neuropathology of organic acidurias: Insights from animal studies
Authors: Wajner M. , Latini A. , Wyse A. T. S. , Dutra‐Filho C. S. 
Published: August 2004

AbstractSummary: Organic acidurias represent a group of inherited disorders resulting from deficient activity of specific enzymes of the catabolism of amino acids, carbohydrates or lipids, leading to tissue accumulation of one or more carboxylic (organic) acids. Patients affected by organic acidurias predominantly present neurological symptoms and structural brain abnormalities, of which the aetiopathogenesis is poorly understood. However, in recent years increasing evidence has emerged suggesting that oxidative stress is possibly involved in the pathology of some organic acidurias and other inborn errors of metabolism. This review addresses some of the recent developments obtained mainly from animal studies indicating oxidative damage as an important determinant of the neuropathophysiology of some organic acidurias. Recent data showing that various organic acids are capable of inducing free radical generation and decreasing brain antioxidant defences is presented. The discussion focuses on the relatively low antioxidant defences of the brain and the vulnerability of this tissue to reactive species. This offers new perspectives for potential therapeutic strategies for these disorders, which may include the early use of appropriate antioxidants as a novel adjuvant therapy, besides the usual treatment based on removing toxic compounds and using special diets and pharmacological agents, such as cofactors and L‐carnitine.
Effect of high‐dose vitamins, coenzyme Q and high‐fat diet in paediatric patients with mitochondrial diseases
Authors: Panetta J. , Smith L. J. , Boneh A. 
Published: August 2004

AbstractSummary: We reviewed the medical records of all patients with confirmed mitochondrial diseases treated with any or all of thiamin, riboflavin, coenzyme Q, vitamin C (~10 mg/kg per day) and a high‐fat diet (50–60% of caloric intake) between 1997 and 2003. There were 15 patients (9 male): 10 had enzymatic deficiency and 10 had a molecular diagnosis. Age at diagnosis was 11 months to 17 years 10 months. Treatment was commenced at time of clinical diagnosis in 12 patients. Follow‐up period was 3 days to 7 years (median 22 months). Improvement was reported in 9 patients, of whom 4 attained further developmental skills, but this was only temporary in 6 patients. Five patients died during the follow‐up period (3 days to 7 years). Patients with the 3243A > G mutation showed no significant change in the course of their disease, except for fewer migraine attacks. Of the six patients who had seizures, one has had a significant reduction in the severity of the seizures and one has had no further seizures. Plasma lactate levels were noncontributory. We conclude that high‐dose vitamin and cofactor treatment and, where applicable, high‐fat diet, are well tolerated and possibly effective in the short term, but ineffective in the longer term.
Successful pregnancy after combined renal–hepatic transplantation in glycogen storage disease type Ia
Authors: Lee P. J. , Muiesan P. , Heaton N. 
Published: August 2004

AbstractSummary: Reports of liver and kidney transplantation and of pregnancy in glycogen storage disease type Ia (GSD Ia) (McKusick 232200) are rare. We report an individual who experienced all three successfully.
Kelley–Seegmiller syndrome due to a new variant of the hypoxanthine–guanine phosphoribosyltransferase (I136T) encoding gene (HPRT Marseille)
Authors: Dussol B. , Ceballos‐Picot I. , Aral B. , Castera V. , Philip N. , Berland Y. 
Published: August 2004

AbstractSummary: A patient with hyperuricaemia and gouty arthritis due to a new variant of hypoxanthine–guanine phosphoribosyltransferase is described. The mutation (I136T, HPRT Marseille) is in the phosphoribosylpyrophosphate‐binding region of the gene and leads to almost total loss of enzyme activity in erythrocytes, with 5% in lymphocytes. Nevertheless, the patient showed no neurological abnormality.
The benefits of liver transplantation in glycogenosis type Ib
Authors: Bhattacharya K. , Heaton N. , Rela M. , Walter J. H. , Lee P. J. 
Published: August 2004

AbstractSummary: There are few reports of liver transplantation in glycogenosis type Ib (GSD Ib). We present two cases who had dramatic catch‐up growth and reduced infections after transplantation, despite persistent neutropenia.
A core catalytic domain of the TyrA protein family: arogenate dehydrogenase from Synechocystis
Authors: BONNER Carol A. , JENSEN Roy A. , GANDER John E. , KEYHANI Nemat O. 
Published: August 2004

The TyrA protein family includes prephenate dehydrogenases, cyclohexadienyl dehydrogenases and TyrAas (arogenate dehydrogenases). tyrAa from Synechocystis sp. PCC 6803, encoding a 30 kDa TyrAa protein, was cloned into an overexpression vector in Escherichia coli. TyrAa was then purified to apparent homogeneity and characterized. This protein is a model structure for a catalytic core domain in the TyrA superfamily, uncomplicated by allosteric or fused domains. Competitive inhibitors acting at the catalytic core of TyrA proteins are analogues of any accepted cyclohexadienyl substrate. The homodimeric enzyme was specific for L-arogenate (Km=331 μM) and NADP+ (Km=38 μM), being unable to substitute prephenate or NAD+ respectively. L-Tyrosine was a potent inhibitor of the enzyme (Ki=70 μM). NADPH had no detectable ability to inhibit the reaction. Although the mechanism is probably steady-state random order, properties of 2′,5′-ADP as an inhibitor suggest a high preference for L-arogenate binding first. Comparative enzymology established that both of the arogenate-pathway enzymes, prephenate aminotransferase and TyrAa, were present in many diverse cyanobacteria and in a variety of eukaryotic red and green algae.
Expression of taurine transporter is regulated through the TonE (tonicity-responsive element)/TonEBP (TonE-binding protein) pathway and contributes to cytoprotection in HepG2 cells
Authors: ITO Takashi , FUJIO Yasushi , HIRATA Mayo , TAKATANI Tomoka , MATSUDA Takahisa , MURAOKA Satoko , TAKAHASHI Kyoko , AZUMA Junichi 
Published: August 2004

In hypertonic environment, taurine accumulates in cells via activation of TauT (taurine transporter) as an adaptive regulation. Recent studies revealed that TonE (tonicity-responsive element)/TonEBP (TonE-binding protein) pathway regulated the expression of various molecules which protect cells against hypertonic stress. In the present study, we investigated the osmoregulatory mechanisms of TauT expression. TauT was up-regulated at both functional and transcriptional levels in HepG2 under hypertonic condition. The TonE site was identified in the promoter region of TauT gene. Reporter gene assay revealed that promoter activity was increased under hypertonic conditions, whereas deletion or mutation of TonE sequence abolished the induction of the promoter activity in response to hypertonicity. By using the reporter gene plasmids containing a TonE site of TauT promoter (p2xTonE-Luc), it was demonstrated that a TonE site was sufficient for the hypertonicity-mediated activation of TauT promoter. Importantly, co-transfection of TauT promoter gene plasmid with wild-type TonEBP expression vector enhanced promoter activity under isotonic conditions, whereas dominant-negative TonEBP abrogated the TauT promoter activity induced by hypertonicity. Finally, treatment with taurine prevented HepG2 cells from cell death induced by hypertonic medium. These findings suggested that induction of TauT by hypertonicity is mediated by the activation of the TonE/TonEBP pathway and confers resistance to hypertonic stress.
Lysophosphatidic acid attenuates the cytotoxic effects and degree of peroxisome proliferator-activated receptor γ activation induced by 15-deoxyΔ12,14-prostaglandin J2 in neuroblastoma cells
Authors: RODWAY Helen A. , HUNT Alan N. , KOHLER Janice A. , POSTLE Anthony D. , LILLYCROP Karen A. 
Published: August 2004

PPARγ (peroxisome proliferator-activated receptor γ) is a ligand-activated transcription factor that responds to 15dPGJ2 (15-deoxy-Δ12,14-prostglandin J2). 15dPGJ2, in vitro, halts neuroblastoma cell growth, but reported mechanisms vary. Here we evaluated the modulatory effects of endogenous serum lipid mitogens upon the extent of 15dPGJ2-induced growth inhibition and on the precise cellular responses of neuroblastoma cells to PPARγ activation. We show that 15dPGJ2 specifically inhibited cell growth in both complete and delipidated media. 15dPGJ2-induced growth inhibition was accompanied by decreased cell viability, although the effect was far more marked in delipidated medium than in complete medium. Incubation with 15dPGJ2 in complete medium resulted in cytoplasmic changes characteristic of type II programmed cell death (autophagy), while prior serum lipid removal resulted in cell death via an apoptotic mechanism. These distinct, serum lipid-dependent cellular responses to 15dPGJ2 were accompanied by increases in the expression of a reporter gene construct containing a PPAR response element of 2.3-fold in complete medium, but of 4.8-fold in delipidated medium. Restoration of the serum lysolipid LPA (lysophosphatidic acid) to cells in delipidated medium reduced 15dPGJ2-mediated PPARγ activation, growth inhibition and cell death; following addition of S1P (sphingosine 1-phosphate), decreases were apparent but more marginal. Further, while the effects of LPA in delipidated medium were mediated through a Gi/phosphoinositide 3-kinase/MAPK (mitogen-activated protein kinase) pathway, those of S1P did not involve the MAPK component. These data suggest that the serum lysolipid LPA modulates the degree of PPARγ activation and the precise cellular response to 15dPGJ2 via activation of a Gi/phosphoinositide 3-kinase/MAPK pathway.
Kinetics of NO and O2 binding to a maleimide poly(ethylene glycol)-conjugated human haemoglobin
Authors: VANDEGRIFF Kim D. , BELLELLI Andrea , SAMAJA Michele , MALAVALLI Ashok , BRUNORI Maurizio , WINSLOW Robert M. 
Published: August 2004

The hypertensive effect observed with most cell-free haemoglobins has been proposed to result from NO scavenging. However, a newly developed PEG [poly(ethylene glycol)]-conjugated haemoglobin, MalPEG-Hb [maleimide-activated PEG-conjugated haemoglobin], is non-hypertensive with unique physicochemical properties: high O2 affinity, low co-operativity and large molecular radius. It is therefore of interest to compare the ligand-binding properties of MalPEG-Hb with unmodified cell-free HbA (stroma-free human haemoglobin). NO association rates for deoxy and oxyMalPEG-Hb and HbA were found to be identical. These results confirm the lack of correlation between hypertension and NO for a similar modified haemoglobin with high molecular radius and low p50 (pO2 at which haemoglobin is half-saturated with O2) [Rohlfs, Bruner, Chiu, Gonzales, Gonzales, Magde, Magde, Vandegriff and Winslow (1998) J. Biol. Chem. 273, 12128–12134]. The R-state O2 association kinetic constants were also the same for the two haemoglobins. However, even though the p50 of MalPEG-Hb is approx. half of that of HbA, the biphasic O2 dissociation rates measured at relatively high pO2 (150 Torr) were 2-fold higher, giving rise to a 2-fold lower R-state equilibrium association constant for MalPEG-Hb compared with HbA. Thus the O2 affinity of MalPEG-Hb is higher only at pO2 values lower than the intersection point of the O2 equilibrium curves for MalPEG-Hb and HbA. In summary, the present studies found similar rates of NO binding to HbA and MalPEG-Hb, eliminating the possibility that the lack of vasoactivity of MalPEG-Hb is simply the result of reduced molecular reactivity with NO. Alternatively, the unique O2-binding characteristics with low p50 and co-operativity suggest that the ‘R-state’ conformation of MalPEG-Hb is in a more T-state configuration and restricted from conformational change.
Characterization of Prismalin-14, a novel matrix protein from the prismatic layer of the Japanese pearl oyster (Pinctada fucata)
Authors: SUZUKI Michio , MURAYAMA Emi , INOUE Hirotaka , OZAKI Noriaki , TOHSE Hidekazu , KOGURE Toshihiro , NAGASAWA Hiromichi 
Published: August 2004

The mollusc shell is a hard tissue consisting of calcium carbonate and organic matrices. The organic matrices are believed to play important roles in shell formation. In the present study, we extracted and purified a novel matrix protein, named Prismalin-14, from the acid-insoluble fraction of the prismatic layer of the shell of the Japanese pearl oyster (Pinctada fucata), and determined its whole amino acid sequence by a combination of amino acid sequence analysis and MS analysis of the intact protein and its enzymic digests. Prismalin-14 consisted of 105 amino acid residues, including PIYR repeats, a Gly/Tyr-rich region and N- and C-terminal Asp-rich regions. Prismalin-14 showed inhibitory activity on calcium carbonate precipitation and calcium-binding activity in vitro. The scanning electron microscopy images revealed that Prismalin-14 affected the crystallization of calcium carbonate in vitro. A cDNA encoding Prismalin-14 was cloned and its expression was analysed. The amino acid sequence deduced from the nucleotide sequence of Prismalin-14 cDNA was identical with that determined by peptide sequencing. Northern-blot analysis showed that a Prismalin-14 mRNA was expressed only at the mantle edge. In situ hybridization demonstrated that a Prismalin-14 mRNA was expressed strongly in the inner side of the outer fold of the mantle. These results suggest that Prismalin-14 is a framework protein that plays an important role in the regulation of calcification of the prismatic layer of the shell.
Metal-binding mechanism of Cox17, a copper chaperone for cytochrome c oxidase
Authors: PALUMAA Peep , KANGUR Liina , VORONOVA Anastassia , SILLARD Rannar 
Published: August 2004

Cox17, a copper chaperone for cytochrome c oxidase, is an essential and highly conserved protein. The structure and mechanism of functioning of Cox17 are unknown, and even its metalbinding stoichiometry is elusive. In the present study, we demonstrate, using electrospray ionization–MS, that porcine Cox17 binds co-operatively four Cu+ ions. Cu4Cox17 is stable at pH values above 3 and fluorescence spectra indicate the presence of a solvent-shielded multinuclear Cu(I) cluster. Combining our results with earlier EXAFS results on yeast CuCox17, we suggest that Cu4Cox17 contains a Cu4S6-type cluster. At supramillimolar concentrations, dithiothreitol extracts metals from Cu4Cox17, and an apparent copper dissociation constant KCu=13 fM was calculated from these results. Charge-state distributions of different Cox17 forms suggest that binding of the first Cu+ ion to Cox17 causes a conformational change from an open to a compact state, which may be the rate-limiting step in the formation of Cu4Cox17. Cox17 binds non-co-operatively two Zn2+ ions, but does not bind Ag+ ions, which highlights its extremely high metal-binding specificity. We further demonstrate that porcine Cox17 can also exist in partly oxidized (two disulphide bridges) and fully oxidized (three disulphide bridges) forms. Partly oxidized Cox17 can bind one Cu+ or Zn2+ ion, whereas fully oxidized Cox17 does not bind metals. The metal-binding properties of Cox17 imply that, in contrast with other copper chaperones, Cox17 is designed for the simultaneous transfer of up to four copper ions to partner proteins. Metals can be released from Cox17 by non-oxidative as well as oxidative mechanisms.
Quantitative description of the interaction between folate and the folate-binding protein from cow's milk
Authors: NIXON Peter F. , JONES Marc , WINZOR Donald J. 
Published: August 2004

A detailed study has been carried out on the dependence of folate binding on the concentration of FBP (folate-binding protein) at pH 5.0, conditions selected to prevent complications arising from the pre-existing self-association of the acceptor. In contrast with the mandatory requirement that reversible interaction of ligand with a single acceptor site should exhibit a unique, rectangular hyperbolic binding curve, results obtained by ultrafiltration for the FBP–folate system required description in terms of (i) a sigmoidal relationship between concentrations of bound and free folate and (ii) an inverse dependence of affinity on FBP concentration. These findings have been attributed to the difficulties in determining the free ligand concentration in the FBP–folate mixtures for which reaction is essentially stoichiometric. This explanation also accounts for the similar published behaviour of the FBP–folate system at neutral pH, which had been attributed erroneously to acceptor self-association, a phenomenon incompatible with the experimental findings because of its prediction of a greater affinity for folate with increasing FBP concentration.
Glutamine availability up-regulates expression of the amino acid transporter protein ASCT2 in HepG2 cells and stimulates the ASCT2 promoter
Authors: BUNGARD Claire I. , McGIVAN John D. 
Published: August 2004

Glutamine transport into the human hepatoma cell line HepG2 is catalysed primarily by an ASCT2-type transporter identical in sequence with that cloned previously from JAR cells. An antibody raised against the C-terminus of the ASCT2 protein was shown to recognize ASCT2 on Western blots. Using this antibody, it was found that variation in cell growth rate did not affect ASCT2 expression, but both growth rate and ASCT2 expression were significantly reduced by glutamine deprivation. Expression of a number of other proteins was shown to be unaffected under these conditions. The sequence of the 5′-flanking region of the ASCT2 gene was derived from the human genome database. A 907 bp fragment of this sequence was directionally ligated into a luciferase reporter vector and was shown to exhibit promoter activity when transfected into HepG2 cells. Promoter activity was greatly reduced when transfection was performed in glutamine-free medium and was restored when glutamine was added post-transfection. The absence of other essential amino acids did not affect promoter activity, and glutamine deprivation did not affect the MCT1 (monocarboxylate transporter 1) promoter. These results indicate that both ASCT2 promoter activity and ASCT2 protein expression in these cells are dependent on glutamine availability.