bluuebunny/crossref_metadata_2025 huggingface dataset:
Structure and dynamics of the human pleckstrin DEP domain: Distinct molecular features of a novel DEP domain subfamily
Authors: Civera Concepcion , Simon Bernd , Stier Gunter , Sattler Michael , Macias Maria J.
Published: November 2004

Pleckstrin1 is a major substrate for protein kinase C in platelets and leukocytes, and comprises a central DEP (disheveled, Egl‐10, pleckstrin) domain, which is flanked by two PH (pleckstrin homology) domains. DEP domains display a unique α/β fold and have been implicated in membrane binding utilizing different mechanisms. Using multiple sequence alignments and phylogenetic tree reconstructions, we find that 6 subfamilies of the DEP domain exist, of which pleckstrin represents a novel and distinct subfamily. To clarify structural determinants of the DEP fold and to gain further insight into the role of the DEP domain, we determined the three‐dimensional structure of the pleckstrin DEP domain using heteronuclear NMR spectroscopy. Pleckstrin DEP shares main structural features with the DEP domains of disheveled and Epac, which belong to different DEP subfamilies. However, the pleckstrin DEP fold is distinct from these structures and contains an additional, short helix α4 inserted in the β4‐β5 loop that exhibits increased backbone mobility as judged by NMR relaxation measurements. Based on sequence conservation, the helix α4 may also be present in the DEP domains of regulator of G‐protein signaling (RGS) proteins, which are members of the same DEP subfamily. In pleckstrin, the DEP domain is surrounded by two PH domains. Structural analysis and charge complementarity suggest that the DEP domain may interact with the N‐terminal PH domain in pleckstrin. Phosphorylation of the PH–DEP linker, which is required for pleckstrin function, could regulate such an intramolecular interaction. This suggests a role of the pleckstrin DEP domain in intramolecular domain interactions, which is distinct from the functions of other DEP domain subfamilies found so far. Proteins 2005. © 2004 Wiley‐Liss, Inc.
High affinity fucose binding of Pseudomonas aeruginosa lectin PA‐IIL: 1.0 Å resolution crystal structure of the complex combined with thermodynamics and computational chemistry approaches
Authors: Mitchell Edward P. , Sabin Charles , Šnajdrová Lenka , Pokorná Martina , Perret Stéphanie , Gautier Catherine , Hofr Ctirad , Gilboa‐Garber Nechama , Koča Jaroslav , Wimmerová Michaela , Imberty Anne
Published: November 2004

PA‐IIL is a fucose‐binding lectin from Pseudomonas aeruginosa that is closely related to the virulence factors of the bacterium. Previous structural studies have revealed a new carbohydrate‐binding mode with direct involvement of two calcium ions (Mitchell E, Houles C, Sudakevitz D, Wimmerova M, Gautier C, Peréz S, Wu AM, Gilboa‐Garber N, Imberty A. Structural basis for selective recognition of oligosaccharides from cystic fibrosis patients by the lectin PA‐IIL of Pseudomonas aeruginosa. Nat Struct Biol 2002;9:918–921). A combination of thermodynamic, structural, and computational methods has been used to study the basis of the high affinity for the monosaccharide ligand. A titration microcalorimetry study indicated that the high affinity is enthalpy driven. The crystal structure of the tetrameric PA‐IIL in complex with fucose and calcium was refined to 1.0 Å resolution and, in combination with modeling, allowed a proposal to be made for the hydrogen‐bond network in the binding site. Calculations of partial charges using ab initio computational chemistry methods indicated that extensive delocalization of charges between the calcium ions, the side chains of the protein‐binding site and the carbohydrate ligand is responsible for the high enthalpy of binding and therefore for the unusually high affinity observed for this unique mode of carbohydrate recognition. Proteins 2005. © 2004 Wiley‐Liss, Inc.
Elucidation of information encoded in tryptophan 140 of staphylococcal nuclease
Authors: Hirano Satoshi , Kamikubo Hironari , Yamazaki Yoichi , Kataoka Mikio
Published: November 2004

We investigated the role of W140 in the folding of Staphylococcal nuclease. For this purpose, we constructed the 19 possible substitution mutations at residue 140. Only three mutants, W140F, W140H, and W140Y, adopted native‐like structures under physiological conditions and showed native‐like enzymatic activities. In contrast, the other 16 mutants took on compact unfolded structures under physiological conditions and the enzymatic activities of these mutants were decreased to approximately 70% of wild‐type levels. These 16 mutants maintained substrate‐induced foldability. These results strongly indicate that the side‐chain information encoded by residue 140 is essential to maintain a stable native structure, and that this residue must be an aromatic side chain. The order of thermal stability was wild type > W140H > W140F = W140Y. Therefore, the five‐membered nitrogen‐containing ring of the indole is thought to bear the essential information. In the crystal structure of staphylococcal nuclease, the five‐membered ring is at the local center of the C‐terminal cluster through hydrophobic interactions. This cluster plays a key role in the interaction connecting the C‐terminal region and the N‐terminal β‐core. Mutants other than W140H, W140F, and W140Y lost the ability to form the local core, which caused the loss of the long‐range interactions between the C‐terminal and N‐terminal regions. Inhibitor or substrate binding to these mutants compensates for the lack of long‐range interactions generated by W140. Proteins 2005. © 2004 Wiley‐Liss, Inc.
Evaluation of the performance of iron‐based oxygen scavengers, with comments on their optimal applications
Authors: Miltz Joseph , Perry Michael
Published: November 2004

Oxygen scavengers are commonly used in packaged foods in Japan and much less so in other developed countries, in spite of the advantages that they offer in maintaining quality and extending shelf‐life. The reason stems from the additional cost involved, and even more so because of the lack of sufficient technical information on their performance and the lack of understanding of how to apply them effectively. In the present study the performance of iron‐based oxygen‐scavenging sachets was evaluated. It was found that the actual scavenging capacity is much higher than the ‘nominal’ capacity provided by the manufacturers. Also, a significant distribution in the oxygen absorption capacity exists, even in the same scavenger type. The rate of oxygen scavenging was found to depend on the scavenger type and capacity. It was also found that in an atmosphere containing CO2 (as in MAP applications) the iron‐based oxygen scavengers also absorb CO2. Copyright © 2004 John Wiley & Sons, Ltd.
Evaluation of a hydrogen laser vacuum ultraviolet source for photoionization mass spectrometry of pharmaceuticals
Authors: Finch Jeffrey W. , Toerne Kevin A. , Schram Karl H. , Denton M. Bonner
Published: November 2004

A photoionization hydrogen laser time‐of‐flight mass spectrometer system (H2‐TOFMS) has been evaluated for the rapid analysis of drugs of abuse and pharmaceutical agents extracted from prescription tablets and spiked urine samples. The spectra obtained using the H2‐TOFMS showed primarily intact molecular ions (M+.) after introduction by a heated probe and irradiation with vacuum ultraviolet (VUV) photons from the laser. Samples analyzed by this technique required only a simple solid‐phase extraction step; no chromatographic separation or derivatization was necessary to identify the drugs of abuse or pharmaceutical agents. Copyright © 2004 John Wiley & Sons, Ltd.
Electrospray ionization quadrupole time‐of‐flight and matrix‐assisted laser desorption/ionization tandem time‐of‐flight mass spectrometric analyses to solve micro‐heterogeneity in post‐translationally modified peptides from Phoneutria nigriventer (Aranea, Ctenidae) venom
Authors: Pimenta Adriano M. C. , Rates Breno , Bloch Carlos , Gomes Paulo C. , Santoro Marcelo M. , de Lima Maria Elena , Richardson Michael , Cordeiro Marta do N.
Published: November 2004

Previous studies of the fractionated venom of the Brazilian armed spider Phoneutria nigriventer, obtained by gel filtration, have demonstrated the presence of a fraction PhM, a pool of small peptides (up to 2000 Da) that provoke contractions in smooth muscle of guinea pig ileum. Initial attempts to sequence these peptides were largely unsuccessful because of the low purification yield and the fact that the majority seemed to be blocked at their N‐termini. In the present work, analysis of this venom fraction by mass spectrometry has revealed the existence of a highly complex mixture of peptides with molecular weights corresponding to those observed for the muscle‐active peptides previously described (800–1800 Da). These peptides appear to be a family of isoforms with some particular features. The amino acid sequences of 15 isoforms have been determined by tandem mass spectrometry (MS/MS) using both electrospray ionization quadrupole time‐of‐flight mass spectrometry (ESI‐Q/ToFMS) and matrix‐assisted laser desorption/ionization tandem time‐of‐flight mass spectrometry (MALDI‐ToF/ToFMS). These molecules contain post‐translational modifications such as proteolysis and C‐terminal amidation, which combine to generate additional isoforms. All the isoforms sequenced in this study possess an N‐terminal pyroglutamic acid residue. A search for sequence similarities with other peptides in databanks revealed that these peptides are structurally related to the tachykinins, a family of neuro‐hormone peptides. The data obtained in this study will be essential for the subsequent steps of this research, the synthesis of these peptides and pharmacological characterization of their biological activity. Copyright © 2004 John Wiley & Sons, Ltd.
Tyrosinaemia — treatment and outcome
Authors: Kvittingen E. A.
Published: November 2004

Tyrosinaemia type I is, untreated, a fatal disease: in the acute form from liver failure, in the chronic form often from hepatocellular carcinoma. Acute neurological crisis is also a cause of death. Traditionally the treatment has been with diet, but for a decade liver transplantation has been the ultimate treatment. The continuous production of the pathological metabolites in the kidneys after transplantation appears to be without significance. Introduction of the enzyme inhibitor NTBC in the treatment of tyrosinaemia has reduced the need for liver transplants. Neonatal screening may be justified as efficient treatment has become available. The complex phenotype of lethal albino mice, with severe alterations in gene expression, has been shown to be caused by fumarylacetoacetase deficiency. Prolonged hypoglycaemia in otherwise adequately treated tyrosinaemia patients may result from depressed expression of genes coding for enzymes in gluconeogenesis, as seen in the mouse model. Self‐induced genetic correction in liver tissue that occurs in many tyrosinaemia patients may reduce the risk of liver failure in some patients.
The management and outcome of propionic and methylmalonic acidaemia
Authors: Leonard J. V.
Published: November 2004

The management of the severe variants of methylmalonic and propionic acidaemia remains difficult. With conventional therapy of diet, carnitine and antibiotics, mortality is high and long‐term complications are common. Liver transplantation appears to be an important alternative.
Development of mouse models for cystic fibrosis
Authors: Dorin J. R.
Published: November 2004

Using gene targeting in embryonal stem cells it is now possible to create accurate genetic models of inherited human disease in the mouse. The value of an animal model of cystic fibrosis is in providing clarification of disease pathogenesis, genotype‐phenotype correlation, the identification of other relevant genetic factors, and as the optimal test system for novel therapeutic intervention. Correction of the basic defect by a somatic gene therapy approach is an attractive approach to disease treatment. CF mouse models have been described which display the characteristic electrophysiological defect and thus both safety and efficacy can be monitored in these animals. Modulation ofCftr levels in transgenic animals and the results on disease phenotype give some indication of the level of gene expression necessary to give clinical effect.
Lipid status and fatty acid metabolism in phenylketonuria
Authors: Giovannini M. , Biasucci G. , Agostoni C. , Luotti D. , Riva E.
Published: November 2004

Owing to dietary treatment, patients with phenylketonuria (PKU) are supplied with only small amounts of animal fats and show low blood cholesterol levels and a poor long‐chain polyunsaturated fatty acid (LC‐PUFA) status. Endogenous synthesis should compensate for the physiological need for cholesterol for growth, but supplementary exogenous LC‐PUFA seems advisable. PKU infants could develop depletion of docosahexaenoic acid, fundamental for the functional development of the central nervous system. The availability of arachidonic acid from plasma in PKU has been found to be related to dietary compliance, and seems to influence the synthesis of arachidonate‐derived eicosanoids. Trials of dietary supplementation of PKU patients with oils containing LC‐PUFA are in progress, but the functional consequences of these supplementations need further investigation.
A new diagnostic technique for adenylosuccinate lyase deficiency
Authors: Domkin V. D. , Lazebnik T. A. , Roundeff A. Yu. , Smirnov M. N.
Published: November 2004

A convenient and simple method of diagnosing adenylosuccinate lyase (ASL) deficiency is described. This method consists of (1) isolation of SAICA riboside and S‐Ado with a cation exchange resin; (2) measurement of the UV absorbance of the ammonia eluate at 270 and 250 nm; (3) calculation of theA270/A250 ratio. If the value of this ratio is less than 0.45, the patient has a normal level of ASL activity. If the value of this ratio is greater than 0.70, the patient has ASL deficiency.
Trimethylaminuria, fish odour syndrome: a new method of detection and response to treatment with metronidazole
Authors: Treacy E. , Johnson D. , Pitt J. J. , Danks D. M.
Published: November 2004

Trimethylaminuria is an autosomal recessive disorder involving deficientN‐oxidation of the dietary‐derived amine trimethylamine (TMA). TMA, a volatile tertiary amine, accumulates and is excreted in urine of patients with deficient TMA oxidase activity. Treatment strategies for this condition are limited. We report a new stable‐isotope dilution method for rapid sequential analysis of TMA concentrations and the clinical and biochemical response to treatment with metronidazole.
Familial isolated vitamin E deficiency. Extensive study of a large family with a 5‐year therapeutic follow‐up
Authors: Amiel J. , Maziere J. C. , Beucler I. , Koenig M. , Reutenauer L. , Loux N. , Bonnefont D. , Féo C. , Landrieu P.
Published: November 2004

A major neurological deterioration, beginning with ataxia, led to the diagnosis of familial vitamin E deficiency in a girl. Based upon vitamin E determinations, 4/8 members of the (consanguineous) sibship were considered to be homozygous. Homozygosity was also found for the alleles of six markers linked to theAVED locus, recently identified in similar Tunisian or Sicilian families on chromosome 8q. Measures of vitamin E in lipoprotein fractions and in liver biopsy after vitamin E oral load suggested that free diffusion of vitamin E between the different compartments was possible and even increased. However, a high‐affinity ligand seemed to be lacking, either in the hepatic recycling of vitamin E or in both the hepatic and the other vitamin E compartments. The 5‐year substitutive treatment was successful only in the pre‐ or paucisymptomatic patients. Serum vitamin E must be measured in any unexplained progressive ataxia.
Diagnosis of Zellweger syndrome by analysis of very long‐chain fatty acids in stored blood spots collected at neonatal screening
Authors: Jakobs C. , van den Heuvel C. M. M. , Stellaard F. , Largillière C. , Skovby F. , Christensen E.
Published: November 2004

Zellweger syndrome was diagnosedpost mortem by determining the very long‐chain fatty acids in a blood spot collected at neonatal screening.
Skin fibroblast carnitine uptake in secondary carnitine deficiency disorders
Authors: Tein I. , De Vivo D. C. , Ranucci D. , DiMauro S.
Published: November 2004

Skin fibroblast carnitine uptake studies may identify and differentiate primary and secondary carnitine deficiency disorders. To confirm the specificity of these studies in differentiating primary from secondary carnitine deficiency disorders, we have studied carnitine uptake in the cultured skin fibroblasts from 5 children who have various enzymatic defects in intramitochondrial β‐oxidation including short‐chain, medium‐chain and long‐chain acyl‐CoA dehydrogenase and short‐chainl‐3‐hydroxyacyl‐CoA dehydrogenase deficiencies, and in 4 children with cytochrome oxidase deficiency. Carnitine uptake was normal in the intramitochondrial β‐oxidation cases, suggesting other mechanisms for their carnitine deficiency. Therefore, intramitochondrial β‐oxidation defects associated with carnitine deficiency can be differentiated from primary carnitine deficiency not only by the presence of an abnormal dicarboxylic aciduria but by normal skin fibroblast carnitine uptake. In contrast to these findings, carnitine uptake in the cultured skin fibroblasts of four children with secondary carnitine deficiency due to cytochrome oxidase deficiency demonstrated a partial decrease in the maximal velocity of uptake (20–47% controlVmax), similar to that observed in the primary carnitine deficiency heterozygotes. We propose that this observation may be due to a generalized decrease in intracellular ATP, thus decreasing the efficiency of the energy‐ and sodium‐dependent carnitine transporter. We conclude that carnitine uptake studies in cultured skin fibroblasts will contribute to an understanding of the mechanisms of carnitine depletion in the primary and secondary carnitine deficiency disorders.
Inhibition of succinate dehydrogenase and β‐hydroxybutyrate dehydrogenase activities by methylmalonate in brain and liver of developing rats
Authors: Dutra J. C. , Dutra‐Filho C. S. , Cardozo S. E. C. , Wannmacher C. M. D. , Sarkis J. J. F. , Wajner M.
Published: November 2004

The effects of methylmalonate (MMA) on succinate dehydrogenase (SDH) and β‐hydroxybutyrate dehydrogenase (HBDH) activities in brain and liver of 15‐day‐old rats were studied. The apparentKm of SDH for succinate was 0.45 mmol/L in brain and 0.34 mmol/L in liver. MMA inhibited the enzyme activity in both tissues withKi values of 4.5 mmol/L and 2.3 mmol/L in brain and liver, respectively, and the inhibition was of the reversible competitive type. The calculatedKm for HBDH with β‐hydroxybutyrate as substrate was 1.26 mmol/L in brain and 0.36 mmol/L in liver. MMA inhibited the enzyme with aKi value of 0.015 mmol/L in brain and 0.275 mmol/L in liver. These results are probably relevant to our understanding of cerebral metabolism in methylmalonic acidaemic children, especially during ketoacidotic and hypoglycaemic crises, and may be related to the pathogenesis of cerebral dysfunction of methylmalonic acidaemia.
Molecular genetics of metachromatic leukodystrophy
Authors: Gieselmann V. , Polten A. , Kreysing J. , von Figura K.
Published: November 2004

Metachromatic leukodystrophy is a lysosomal storage disorder caused by the deficiency of arylsulphatase A. The disease is characterized by a progressive demyelination that causes a variety of neurological symptoms. Patients die within a few years after the age of onset. Clinically the disease is heterogeneous and according to the age of onset three different forms can be distinguished. The gene of arylsulphatase A has been cloned and several mutations causing metachromatic leukodystrophy have been characterized. The distribution of these alleles among patients with different clinical forms of the disease has revealed a genotype‐phenotype correlation. A major determinant of the clinical phenotype is the residual enzyme activity that it associated with a particular genotype. Homozygosity for alleles that do not allow the synthesis of arylsulphatase A polypeptides causes the most severe form of disease, whereas homozygosity for alleles that encode arylsulphatase A with low residual enzyme activity is found in the mild late‐onset forms of disease. A substantial arylsulphatase A deficiency can also be found in healthy individuals at high frequency. This phenomenon has been termed pseudodeficiency. It is often difficult to distinguish whether an arylsulphatase A deficiency is due to metachromatic leukodystrophy or harmless pseudodeficiency. The characterization of the mutations causing pseudodeficiency has allowed the detection of the pseudodeficiency allele in the DNA of probands and has thus improved the diagnosis and genetic counselling for metachromatic leukodystrophy.
Tetrahydrobiopterin deficiency and brain nitric oxide synthase in thehph1 mouse
Authors: Brand M. P. , Heales S. J. R. , Land J. M. , Clark J. B.
Published: November 2004

Tetrahydrobiopterin (BH4) is the cofactor for the aromatic amino acid monoxygenase group of enzymes and for all known isoforms of nitric oxide synthase (NOS). Inborn errors of BH4 metabolism lead to hyperphenylalaninaemia and impaired catecholamine and serotonin turnover. The effects of BH4 deficiency on brain nitric oxide (NO) metabolism are not known. In this study we have used thehph‐1 mouse, which displays GTP cyclohydrolase deficiency, to study the effects of BH4 deficiency on brain NOS. In the presence of exogenous BH4, NOS specific activity was virtually identical in the control andhph‐1 preparations. However, omission of BH4 from the reaction buffer led to a significant 20% loss of activity in thehph‐1 preparations only. TheKm for arginine was virtually identical for the control andhph‐1 NOS when BH4 was present in the reaction buffer. In the absence of cofactor, theKm for arginine was 3‐fold greater for control and 5‐fold greater forhph‐1 preparations. It is concluded that (a) BH4 does not regulate the intracellular concentration of brain NOS; (b) less binding of BH4 to NOS occurs in BH4 deficiency states; (c) BH4 has a potent effect on the affinity of NOS for arginine; and (d) the availability of arginine for NOS activity may become severely limiting in BH4 deficiency states. Since, in the presence of suboptimal concentrations of BH4 or arginine, NOS may additionally form oxygen free‐radicals, it is postulated that in severe BH4 deficiency states NO formation is impaired and the central nervous system is subjected to increased oxidative stress.
Neuropathology of peroxisomal diseases
Authors: Martin J. ‐J.
Published: November 2004

This paper gives a description of the essential neuropathological techniques applied to the study of metabolic disorders affecting the nervous system. Subsequently, the neuropathological features of a series of peroxisomal disorders are described with special attention being paid to adrenoleukodystrophy.
Immunocytochemical localization of peroxisomal proteins in human liver and kidney
Authors: Espeel M. , Van Limbergen G.
Published: November 2004

The sample preparation and immunocytochemical methods for investigating the presence and subcellular localization of peroxisomal proteins (catalase, the three β‐oxidation enzymes, alanine: glyoxylate aminotransferase and a peroxisomal membrane protein) in human liver biopsies are described. We present a protocol for immunolabelling on ultrathin and semithin sections from the same tissue block, with protein A‐colloidal gold as a reporter system. For this purpose, the tissue is embedded in Unicryl, a hydrophilic acrylic resin that is cured by ultraviolet illumination at 2°C. The limitations and possibilities of the methods are discussed together with methodological problems. Cryostat sections of prefixed material should be used for the visualization by light microscopy of cytoplasmic catalase. It is emphasized that immunolabelling for catalase in formalin‐fixed archival liver samples and in liver autopsy tissue (in the latter also for the peroxisomal β‐oxidation enzymes) permits visualization of peroxisomes; this can be helpful in diagnosing an index case retrospectively.
Applications of a new fluorimetric enzyme assay for the diagnosis of aspartylglucosaminuria
Authors: Vozyi Ya. V. , Keulemans J. L. M. , Lleijer W. J. , Aula P. , Gray G. R. , van Diggelen O. P.
Published: November 2004

L‐Aspartic acid‐β‐7‐amido‐4‐methylcoumarin is a sensitive and specific fluorogenic substrate for lysosomal glycoasparaginase (aspartylgluco‐saminidase). Fibroblasts and leukocytes from 8 patients with aspartylglucosaminuria, showed 1–7% of the mean normal glycoasparaginase activity. Heterozygotes showed intermediate activities. Glycoasparaginase activity in chorionic villi, cultured trophoblasts, cultured amniotic fluid cells and amniotic fluid was readily detectable, indicating that prenatal analysis of aspartylglucosaminuria should be possible with this assay. β‐Aspartyl‐4‐methylumbelliferone was synthesized but this potential substrate can not be used to assay glycoasparaginase since it hydrolyses spontaneously.
A fluorimetric enzyme assay for the diagnosis of Sanfilippo disease type D (MPS IIID)
Authors: He Wang , Voznyi Ya. V. , Boer A. M. , Kleijer W. J. , van Diggelen O. P.
Published: November 2004

4‐Methylumbelliferyl‐α‐N‐acetylglucosamine 6‐sulphate was synthesized and shown to be a substrate for the lysosomalN‐acetylglucosamine‐6‐sulphate sulphatase (GlcNAc‐6S sulphatase). Fibroblasts and leukocytes from 3 different Sanfilippo D patients showed <1% of mean normal GlcNAc‐6S sulphatase activity. The enzymatic liberation of the fluorochrome from 4‐methyl‐umbelliferyl‐α‐N‐acetylglucosamine 6‐sulphate requires the sequential action of the GlcNAc‐6S sulphatase and α‐N‐acetylglucosaminidase. A normal level of α‐N‐acetylglucosaminidase activity was insufficient to complete the hydrolysis of the reaction intermediate 4‐methylumbelliferyl‐α‐N‐acetylgluco‐saminide formed by the GlcNAc‐6S sulphatase. A second incubation in the presence of excess α‐N‐acetyglucosaminidase is needed to avoid underestimation of the GlcNAc‐6S sulphatase activity.
Possible β‐mannosidosis chimera. Altered expression of metabolic perturbations
Authors: Jones M. Z. , Cavanagh K. T. , Kranich R. , Traviss C. , Fujita Y. , Ohta M. , Matsuura F.
Published: November 2004

An aberrant β‐mannosidosis phenotype in a 5‐month‐old triplet goat kid was characterized by a late postnatal onset of mild neurological symptoms. Necropsy examination revealed relatively normal myelination; however, the distribution of cytoplasmic vacuolation in the kidney and brain was similar to that observed in neonatal β‐mannosidosis. Variable engraftment of donor stem cells, resulting from transplacental transfusion of stem cells from a normal sibling during the immunotolerant period, may have modified the expected severe β‐mannosidosis phenotype. This investigation was designed to determine the effects of a possible chimeric state on organ‐specific metabolic perturbations. Residual β‐mannosidase enzyme activity was found in plasma, kidney, liver and spleen but not in brain. Other lysosomal enzyme activities were comparable to normal values. Immunoreactive β‐mannosidase was estimated to be less than 10% of normal levels. Kidney, brain grey matter and brain white matter contained 33%, 12% and 4%, respectively, of the oligosaccharides expected in the organs of β‐mannosidosis animals. There were no detectable oligosaccharides or cytoplasmic vacuolation in the liver or spleen. Studies of this possible chimera provided preliminary evidence for the efficacy of prenatal treatment of early‐onset neurodegenerative disorders.
Mucolipidosis IV fibroblasts synthesize normal amounts of hyaluronic acid
Authors: Goldin E. , Imai Y. , Kaneski C. R. , Pentchev P. G. , Brady R. O. , Hascall V. C.
Published: November 2004

Mucolipidosis IV (ML IV) (McKusick 252650) is an autosomal recessive metabolic disorder that displays signs of both lipid and mucopolysaccharide (glycosaminoglycan) storage. It has been reported that fibroblasts from ML IV patients exhibit abnormally high synthesis of hyaluronic acid in culture. In our search for a biochemical marker that will enable positive identification of ML IV, we studied glycosaminoglycan synthesis in fibroblast cultures from patients with this disease. ML IV and normal control fibroblasts were incubated with [3H]glucosamine and [35S]sulphate. Labelled glycosaminoglycans were extracted from the cell layer and medium. Chondroitin sulphate and hyaluronic acid were determined by analysis of disaccharides after digestion with chondroitinase ABC. Synthesis of neither of these two glycosaminoglycans differed significantly between control and ML IV fibroblasts. Synthesis of hyaluronic acid was nearly linear for 24 h, with mean calculated values of 11.7 ± 1.4 and 14.4 ± 1.6 pg/cell per 24 h in control and ML IV cultures respectively. The variability within the two groups is attributed primarily to population variability and possibly to culture density. These experiments exclude the possibility that a general metabolic defect in hyaluronic acid synthesis is responsible for the ML IV phenotype, nor can such a defect be used as a diagnostic tool for the disease.
Menstrual cycle and gonadal steroid effects on symptomatic hyperammonaemia of urea‐cycle‐based and idiopathic aetiologies
Authors: Grody W. W. , Chang R. J. , Panagiotis N. M. , Matz D. , Cederbaum S. D.
Published: November 2004

We report two female patients, one with a known inborn error of ureagenesis and the other of unknown cause, in whom recurrent, transient episodes of severe hyperammonaemia increased in frequency and severity with sexual maturity and parturition. Both responded to ovarian steroids administered continuously to suppress ovulation and menstruation, and ultimately to simple hysterectomy. These studies suggest a new therapeutic approach to defective ureagenesis in female patients and a relationship between ammonia production or disposal and the menstrual cycle.
Characterization of a point mutation in the pyruvate dehydrogenase E1α gene from two boys with primary lactic acidaemia
Authors: Awata H. , Endo F. , Tanoue A. , Kitano A. , Matsuda I.
Published: November 2004

We report here a novel mutation in the codon for amino acid 263 resulting in the change from arginine to glutamine in the pyruvate dehydrogenase (PDH) E1α gene, in two boys with primary lactic acidaemia, from independent families. The mutation changes an amino acid located between the two serine residues which are the sites of phosphorylation of the subunit protein. In one family, the mutation wasde novo and in the other it was transmitted from mother to son. The amino acid substitution may affect function of the PDH complex via phosphorylation and dephosphorylation of the E1α subunit. Derangement in the regulation of activity of the PDH complex may explain the primary lactic acidaemia in the patients.
Increased urine concentration of subunit c of mitochondrial ATP synthase in neuronal ceroid lipofuscinoses patients
Authors: Wisniewski K. E. , Golabek A. A. , Kida E.
Published: November 2004

In searching for an easily available diagnostic test for the neuronal ceroid lipofuscinoses (NCL), we screened urine collected from 8 late‐infantile and 12 juvenile NCL cases, 8 obligate heterozygotes, and 16 controls for the presence of subunit c of mitochondrial ATP synthase. Subunit c is a component of the storage material in brain and other tissues of various forms of NCL, apart from the infantile form. Using Western blot analysis and the ELISA technique, we have found significantly higher levels of subunit c in the urine of late‐infantile and some juvenile patients. This finding may have clinical application in developing a diagnostic test for NCL.
Phytanic acid α‐oxidase deficiency (Refsum disease) presenting in infancy
Authors: Herbert M. A. , Clayton P. T.
Published: November 2004

This report describes a patient with high serum phytanic acid concentration due to phytanic acid α‐oxidase deficiency (classical Refsum disease). He presented unusually early, hypotonia and developmental delay being apparent by 7 months. A generalized peroxisomal disorder (so‐called ‘infantile Refsum disease’) was excluded by analyses of pristanic acid, very long‐chain fatty acids, bile acids and plasmalogen synthesis. The early presentation raises the possibility ofin utero exposure to phytanate.
Cerebrospinal fluid amino acids, purines and pyrimidines as a tool in the study of metabolic brain diseases
Authors: Gerrits G. P. J. M. , Monnens L. A. H. , Gabreëls F. J. M. , De Abreu R. A. , Koster A. , Trijbels J. M. F.
Published: November 2004

After establishing more extended reference values for amino acids, purines and pyrimidines in cerebrospinal fluid (CSF) in infancy and childhood, we studied 1250 CSF‐aliquots from patients who were undergoing a diagnostic lumbar puncture for diverse clinical indications. Our primary aim was to answer the question whether determination of the concentration of amino acids, purines and pyrimidines in CSF is a useful tool in screening for metabolic disorders in children with unexplained mental retardation.

In unexplained mental retardation (95 patients) we observed varying abnormalities of CSF. These were reproducible in only 2 patients (a decrease of homocarnosine in combination with two unidentified compounds). Striking abnormalities in pyrimidine content which are limited to CSF are found in argininosuccinic aciduria and uraemia. In uraemia a general decrease in amino acids in CSF and increase of γ‐aminobutyric acid (GABA) was observed.

The results obtained indicate that determination of amino acids, purines and pyrimidines in CSF is only of limited value in the diagnosis of unexplained mental retardation.
The inherited leukodystrophies: A clinical overview
Authors: Aicardi J.
Published: November 2004

The leukodystrophies are degenerative diseases that involve primarily the white matter of the brain. The most common leukodystrophies result from known disturbances in the synthesis or catabolism of myelin such as a block in the catabolism of sulphatides and of galactocerebrosides, respectively, in metachromatic leukodystrophy and in Krabbe disease, or from synthesis of an abnormal proteolipid protein in Pelizaeus‐Merzbacher disease. The cause of white matter involvement in other leukodystrophies remains unknown even though metabolic anomalies, such as accumulation of acetylaspartic acid in Canavan disease, have been demonstrated.

Common clinical features of the leukodystrophies include neurological deterioration following a period of normal development, predominant involvement of motor function at least initially, and absence of convulsions or myoclonus. Imaging — especially magnetic resonance — shows changes in density or signal from central white matter.

Most leukodystrophies feature suggestive symptoms and signs such as effects on peripheral nerves' myelin in Krabbe disease and metachromatic leukodystrophy, or X‐linked inheritance and slow deterioration in Pelizaeus‐Merzbacher disease.

Therapy of the leukodystrophies is purely symptomatic in most cases. Trials of bone marrow transplantation are being pursued for metachromatic leukodystrophy and adrenoleukodystrophy.
Canavan disease: Biochemical and molecular studies
Authors: Matalon R. , Kaul R. , Michals K.
Published: November 2004

Deficiency of the enzyme aspartoacylase and the accumulation ofN‐acetylaspartic acid lead to a severe leukodystrophy and spongy degeneration of the brain, Canavan disease (McKusick 271900). Since our discovery in 1988 of the defect in Canavan disease, 144 patients with Canavan disease have been diagnosed in our laboratory. Most of these children are of Ashkenazi Jewish extraction. The level of enzyme activity can be used for carrier testing. Prenatal diagnosis has been difficult using the enzyme assay owing to the low activity of aspartoacylase in cultured chorionic villus samples or amniocytes. The determination ofN‐acetylaspartic acid in the amniotic fluid is another parameter for diagnosis; however, the levels may not always be elevated.

Bovine and human aspartoacylase have been purified in our laboratory. Bovine and human cDNA and genomic clones have been isolated and six exons have been localized. This information is being used for the study of Canavan disease at the molecular level.
Inborn errors and demyelination: MRI and the diagnosis of white matter disease
Authors: Kendall B. E.
Published: November 2004

The progress and extent of myelination can be assessed using magnetic resonance imaging (MRI). Myelination is delayed or diminished in several inherited metabolic abnormalities presenting in early life. Only minimal myelination of the CNS occurs in Pelizaeus‐Merzbacher disease. Dysmyelination tends to produce fairly symmetrical lesions affecting white matter. In many mitochondrial enzyme and some lysosomal defects, the grey matter is also involved. The appearances and in particular the distribution on MRI and/or CT are characteristic in some conditions and the diagnosis is limited in others. Demyelination due to inflammatory disorders typically causes multifocal white matter lesions, recurrent in multiple sclerosis, monophasic in acute disseminated encephalomyelitis, extending in progressive multifocal leukoencephalopathy and classically involving the pons or corpus callosum in myelinolysis. Hypoxic ischaemic lesions may be metabolically induced and simulate primary demyelinating disorders. Mitochondrial enzyme defects in particular may present with stroke‐like appearances. In many of these conditions, diagnosis is biochemical, but imaging has a significant role in suggesting the diagnosis, and documenting progression, response to therapy or complications.
Genetic analysis of Batten disease
Authors: Gardiner R. M.
Published: November 2004

Batten disease, or neuronal ceroid‐lipofuscinosis (CLN) comprises a group of inherited neurodegenerative disorders characterized by the accumulation of autofluorescent lipopigment in neurones. The three main childhood varieties — infantile (CLN1), late‐infantile (CLN2) and juvenile (CLN3) — manifest autosomal recessive inheritance. The basic biochemical defect remains unknown. The strategy of positional cloning is being pursued to elucidate the molecular basis of Batten disease. The infantile disease locus (CLN1) has been mapped by linkage analysis to human chromosome 1p32, and the juvenile disease locus (CLN3) to human chromosome 16p12. In each case marker loci in strong linkage disequilibrium with the disease loci have been identified. Locus heterogeneity between classical late‐infantile CLN (CLN2) and both CLN1 and CLN3 has been demonstrated. Work is in progress to clone CLN1 and CLN3 and to map CLN2. Identification of linked markers has provided a new approach to prenatal diagnosis. The methodology exists for positional cloning of these genes and elucidation of the molecular genetic basis of the ceroid lipofuscinoses.
Proton magnetic resonance spectroscopy studies in lactic acidosis and mitochondrial disorders
Authors: Cross J. H. , Gadian D. G. , Connelly A. , Leonard J. V.
Published: November 2004

Congenital lactic acidoses form a large group of disorders that are commonly associated with profound neurological dysfunction. Difficulties are frequently encountered in establishing a diagnosis, and the mechanisms underlying brain damage are poorly understood. We have performed proton magnetic resonance spectroscopy (1H‐MRS) on 24 patients under investigation for suspected metabolic disorder, and have compared the MRS observations of brain lactate with measurements of cerebrospinal fluid (CSF) lactate. We have shown good concordance between the two types of observation, confirming the value of the CSF measurements. Regional variations in brain lactate are detected in some cases, and these may help to elucidate the mechanisms underlying selective brain damage.
Changing Southern Ocean palaeocirculation and effects on global climate
Authors: MACKENSEN ANDREAS
Published: November 2004

Southern Ocean palaeocirculation is clearly related to the formation of a continental ice sheet on Antarctica and the opening of gateways between Antarctica and the Australian and South American continents. Palaeoenvironmental proxy records from Southern Ocean sediment cores suggest ice growth on Antarctica beginning by at least 40 million years (Ma) ago, and the opening of Tasmania–Antarctic and Drake Passages to deep-water flow around 34 and 31 ± 2 Ma, respectively. So, the Eocene/Oligocene transition appears to mark the initiation of the Antarctic Circumpolar Current and thus the onset of thermal isolation of Antarctica with a first major ice volume growth on East Antarctic. There is no evidence for a significant cooling of the deep ocean associated with this rapid (< 350 000 years) continental ice build-up. After a long phase with frequent ice sheets growing and decaying, in the middle Miocene at about 14 Ma, a re-establishment of an ice sheet on East Antarctica and the Pacific margin of West Antarctica was associated with an increased southern bottom water formation, and a slight cooling of the deep ocean, but with no permanent drop in atmospheric pCO2. During the late Pleistocene on orbital time scales a temporal correlation between changes in atmospheric pCO2 and proxy records of deep ocean temperatures, continental ice volume, sea ice extension, and deep-water nutrient contents is documented. I discuss hypotheses that call for a dominant control of glacial to interglacial atmospheric pCO2 variations by Southern Ocean circulation dynamics. Millennial to centennial climate variability is a global feature, but there is contrasting evidence from various palaeoclimate archives that indicate both interhemispheric synchrony and asynchrony. The role of the Southern Ocean, however, in triggering or modulating climate variability on these time scales only recently received some attention and is not yet adequately investigated.
Bottom water production and its links with the thermohaline circulation
Authors: JACOBS STANLEY S.
Published: November 2004

For more than a century it has been known that the abyssal basins of the world ocean are primarily occupied by relatively cold and fresh waters that originate in the Southern Ocean. Their distinguishing characteristics are acquired by exposure of surface and shelf waters to ‘ventilation’ by the polar atmosphere and to the melting and freezing of ice over and near the Antarctic continental shelf. Subsequent mixing with deep water over the continental slope results in ‘Bottom Water’ that forms the southern sinking limb of the global ‘Thermohaline Circulation.’ Over recent decades, oceanographers have wrestled with a variety of bottom water and thermohaline circulation problems, ranging from basic definitions to forcing and formation sites, source components and properties, generation processes and rates, mixing and sinking, pathways and transports. A brief review of these efforts indicates both advances and anomalies in our understanding of Antarctic Bottom Water production and circulation. Examples from ongoing work illustrate increasing interest in the temporal variability of bottom water in relation to climate change.
The dynamical balance, transport and circulation of the Antarctic Circumpolar Current
Authors: OLBERS DIRK , BOROWSKI DANIEL , VÖLKER CHRISTOPH , WÖLFF JORG-OLAF
Published: November 2004

The physical elements of the circulation of the Antarctic Circumpolar Current (ACC) are reviewed. A picture of the circulation is sketched by means of recent observations from the WOCE decade. We present and discuss the role of forcing functions (wind stress, surface buoyancy flux) in the dynamical balance of the flow and in the meridional circulation and study their relation to the ACC transport. The physics of form stress at tilted isopycnals and at the ocean bottom are elucidated as central mechanisms in the momentum balance. We explain the failure of the Sverdrup balance in the ACC circulation and highlight the role of geostrophic contours in the balance of vorticity. Emphasis is on the interrelation of the zonal momentum balance and the meridional circulation, the importance of diapycnal mixing and eddy processes. Finally, new model concepts are described: a model of the ACC transport dependence on wind stress and buoyancy flux, based on linear wave theory; and a model of the meridional overturning and the mean density structure of the Southern Ocean, based on zonally averaged dynamics and thermodynamics with eddy parametrization.
Evolution and diversity of the benthic fauna of the Southern Ocean continental shelf
Authors: CLARKE ANDREW , ARONSON RICHARD B. , CRAME J. ALISTAIR , GILI JOSEP-MARIA , BLAKE DANIEL B.
Published: November 2004

The modern benthic fauna of the Antarctic continental shelf is characterized by the lack of active, skeleton-breaking (durophagous) predators such as crabs, lobsters and many fish, and the dominance in many areas of epifaunal suspension feeders. It has often been remarked that these ecological characteristics give the fauna a distinctly Palaeozoic feel, with the assumption that it may be an evolutionary relic. We now know that this is not so, and fossil evidence shows clearly that many of the taxa and life-styles that are absent now were previously present. The modern fauna has been shaped by a number of factors, important among which have been oceanographic changes and the onset of Cenozoic glaciation. Sea-water cooling, and periodic fragmentation of ranges and bathymetric shifts in distribution driven by variability in the size and extent of the continental ice cap on Milankovitch frequencies will all have caused both extinction and allopatric speciation. The modern glacial setting with relatively low terrestrial impact away from immediate coastal regions, and scouring by icebergs are the key factors influencing the ecology and population dynamics for the modern Antarctic benthos.
Management of Southern Ocean fisheries: global forces and future sustainability
Authors: CROXALL J.P. , NICOL S.
Published: November 2004

The marine resources of the Antarctic region are of global significance. In managing Southern Ocean marine resources, especially fisheries, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) has adopted principles that aim: to balance harvesting and conservation; to protect the needs of dependent species, and to avoid changes that are irreversible in 20–30 years. CCAMLR has pioneered ecosystem approaches to fishery and environmental management, through the incorporation of precaution and uncertainty into its management procedures and by establishing an ecosystem monitoring programme using indicator species and processes. This pioneering application of precautionary and ecosystem approaches in the management of harvesting has met with some success, notably in applying conservative yield models for toothfish and krill stocks and in establishing strict rules for undertaking new and exploratory fisheries. However, toothfish management has been recently compromised by Illegal, Unreported and Unregulated (IUU) fishing which is driven by forces outside the Southern Ocean. Southern Ocean harvestable resources are also subject to other global forces such as environmental changes, and their management systems remain very vulnerable to rapid shifts in worldwide fishery economics, and to inadequate management in adjacent areas, particularly high seas. CCAMLR needs quickly to develop the basis of more flexible and effective management to cater for rapid shifts in capacity and demand. The complementary task, however, is to raise the management standard of other Regional Fisheries Management Organisations (RFMOs) to those of CCAMLR if global high seas marine resources are to be sustainable for the rest of this century.
The Role of the Southern Ocean in Global Processes
Authors: FAHRBACH EBERHARD
Published: November 2004

The limits of the Southern Ocean and its importance have been under debate for a long time. However, with growing knowledge, it has become obvious that the circum-Antarctic water belt is the defining limit and that the Southern Ocean plays an active and important role in the physical part of the global climate system, the global carbon cycle and biogeochemical processes.