bluuebunny/crossref_metadata_2025 huggingface dataset:
The contribution of polyploidy to variation in Brassica species
Authors: Osborn Thomas C.
Published: August 2004

The genus Brassica includes species with two levels of polyploidy: diploids that have replicated genomes and appear to be ancient polyploids, and allopolyploids that were recently derived from hybridization of the diploid species. Research on these species has provided evidence that polyploidy contributes to phenotypic variation through several mechanisms. Polyploidy increases the potential variation of dosage‐regulated gene expression, and this mechanism appears to affect flowering time variation through the effects of replicated copies of the flowering time gene FLC. Homoeologous chromosome transpositions occur in allopolyploids that alter allele composition, and this has created novel flowering time variation in newly formed Brassica allopolyploids. New allopolyploids also may have epigenetic changes or altered regulatory interactions that affect gene expression and phenotypic variation. Continued research on Brassica and other species should provide insight into the relative importance of these mechanisms for generating novel variation in polyploids.
Expression of a bacterial asparagine synthetase gene in oilseed rape (Brassica napus) and its effect on traits related to nitrogen efficiency
Authors: Seiffert Beatrix , Zhou Zewen , Wallbraun Michael , Lohaus Gertrud , Möllers Christian
Published: August 2004

The investigation and improvement of nitrogen efficiency in oilseed rape (Brassica napus L.) are important issues in rapeseed breeding. The objective of this study was to modify ammonium assimilation in transgenic rapeseed plants through the expression of the Escherichia coli asparagine synthetase (AsnA, E.C. 6.3.1.1) gene under the control of the cauliflower mosaic virus (CaMV) 35S promoter, and to study its influence on amino acid composition in leaves and on seed traits related to nitrogen efficiency. In regenerated transgenic plants, the 37 kDa AsnA protein was detected by Western blot analysis, but was lacking in untransformed control plants of cv. Drakkar. In the transformants, in vitro asparagine synthetase activities ranged from 105 to 185 nmol asparagine mg−1 protein h−1, whereas, in untransformed control plants, only negligible asparagine synthetase activities of up to 5 nmol asparagine mg−1 protein h−1 were found. Despite these significant activities, no changes in the amino acid composition in the leaves or in the phloem of transgenic plants were detectable. In a pot experiment, two transgenic lines expressing the prokaryotic asparagine synthetase clearly performed inferiorly to control plants at limiting nitrogen (N) fertilizer supply. Although the seed N content was increased, the seed yield and the seed N yield were reduced, which was interpreted as an increased nitrate assimilation leading, at limiting N supply, to a reduced seed yield and seed N yield. At high N fertilizer supply, the differences were less pronounced for one transgenic line, whereas the other showed a higher seed N yield and an improved nitrogen harvest index. The results show that the expression of the E. coli asnA gene in oilseed rape could be of advantage at high N supply, but not at limiting N fertilizer supply.
Ozone symptoms in leaves of woody plants in open‐top chambers: ultrastructural and physiological characteristics
Authors: Gravano Elisabetta , Bussotti Filippo , Strasser Reto J. , Schaub Marcus , Novak Kristopher , Skelly John , Tani Corrado
Published: August 2004

This study was carried out in the summer of 2001 at the Lattecaldo open‐top chamber research facility (Canton Ticino, southern Switzerland). The aim of this research study was to examine the behaviour of Fraxinus excelsior, Prunus avium and Viburnum lantana seedlings grown in charcoal‐filtered (CF) (∼ 50% of the ambient O3) and non‐filtered (NF) (∼ 92% of the ambient O3) air open‐top chambers. Investigations included the assessment of visible foliar symptom development, anatomical and ultrastructural analysis of symptoms, measurements of direct chlorophyll a fluorescence (fluorescence findings were processed by means of the JIP test) and leaf gas exchange measurements. The three species displayed different foliar symptoms. In F. excelsior, symptoms consisted of punctiform stipples with necrotic cells (hypersensitive response, HR), whereas, in P. avium and V. lantana, reddening developed, revealing the accumulation of anthocyanins. In V. lantana, symptoms appeared earlier than in the other species; in F. excelsior, symptoms developed more rapidly and led to premature leaf abscission. In F. excelsior, at least at the beginning, the onset of symptoms was combined with an enhanced photosynthetic efficiency (compensation mechanism), whereas, in P. avium and V. lantana, this efficiency progressively decreased. The fluorescence parameters most closely connected to ozone stress were as follows: a reduction in performance index (PIABS) and active reaction centres (RC/CS0), and an increase in the variable fluorescence relative to 30 ms (VI) and of the dissipation processes. Dissipation is a form of defence mechanism against oxidative stress and is related to the role of the deactivated reaction centres (the silent centres) as well as anthocyanins. Symptom development correlated in all three species with the reduction in reaction centres. Symptomatic leaves had a lower net photosynthetic rate (Pn). Net photosynthesis correlated with the reduction in VI, which suggests an accumulation of reduced plastoquinone, produced in the luminous phase of photosynthesis, which was not capable of reaching the dark phase reactions.
Photosynthetic rates and partitioning of absorbed light energy in photoinhibited leaves
Authors: Hikosaka Kouki , Kato Masaharu C. , Hirose Tadaki
Published: August 2004

Parameters for the evaluation of the effects of photoinhibition on photosynthetic carbon gain were studied in Chenopodium album leaves. The light‐response curve of photosynthetic rate was determined at 36 Pa CO2 partial pressure and fitted by a non‐rectangular hyperbola. Both the initial slope of the curve and the light‐saturated rate decreased in photoinhibited leaves, although the decrease in the latter was small. The convexity of the curve was also smaller in photoinhibited leaves. The capacities of ribulose‐1,5‐bisphosphate carboxylation (Vcmax) and electron transport (Jmax) were estimated from the CO2‐response curves. Vcmax and Jmax decreased similarly with increasing photoinhibition. Energy partitioning in photosystem II (PSII) was estimated using chlorophyll fluorescence parameters. The fraction of energy that was consumed by photochemistry decreased with increasing photoinhibition. However, an increase in inactive PSII, decreasing energy partitioning to active PSII, relaxed the excitation pressure in PSII, and led to a reduction in the fraction of excess energy that was neither consumed by photochemistry nor dissipated as heat.
Growth and photosynthesis of virus‐infected and virus‐eradicated orchid plants exposed to different growth irradiances under natural tropical conditions
Authors: He Jie , Ouyang Wen , Chia Tet Fatt
Published: August 2004

Responses of virus‐infected (VI) and virus‐eradicated (VE) Oncidium Gower Ramsey orchid plants grown under 30% of prevailing solar radiation and those transferred from 30 to 60% and 100% of prevailing solar radiation were studied under natural tropical conditions. Plants grown under 30% of prevailing solar radiation suffered lower leaf and floral production and reduced photosynthesis. When the irradiance was increased to 60% of prevailing solar radiation, enhancement of leaf and floral production and photosynthetic capacities were achieved. However, when the plants were transferred from 30 to 100% of prevailing solar radiation, the growth and photosynthetic capacities of the plants were significantly reduced. All plants exhibited a midday depression in photosynthetic CO2 assimilation (A), stomatal conductance (gs) and Fv/Fm ratio. The degree of midday depression of these parameters was not only associated with high temperatures and high irradiances but also with virus infection. Midday Fv/Fm ratio depression indicated that dynamic photo‐inhibition occurred in all plants grown under all three light conditions. However, chronic photo‐inhibition, measured by pre‐dawn Fv/Fm ratio and chlorophyll content, occurred only in those plants transferred from 30 to 100% of prevailing solar radiation. Hence, it is concluded that the VI Oncidium Gower Ramsey was more susceptible to high irradiance than the VE plants.
cDNA cloning and characterization of a new stress‐responsive gene BoRS1 from Brassica oleracea var. acephala
Authors: Tang Dongqin , Qian Hongmei , Yu Shunwu , Cao Youfang , Liao Zhihua , Zhao Lingxia , Sun Xiaofen , Huang Danfeng , Tang Kexuan
Published: August 2004

A new stress‐responsive gene BoRS1 (GenBank accession No. AY373021) was isolated from Brassica oleracea var. acephala by rapid amplification of cDNA ends (RACE). The full‐length cDNA of BoRS1 was 2076 bp and contained a 1851 bp open reading frame (ORF) encoding 617 amino acids. Sequence analysis indicated that the deduced BoRS1 shared some identities with LTI65, RD29A, RD29B and COR78 from Arabidopsis thaliana. Southern blot analysis of genomic DNA indicated that other related genes existed and there were two copies of BoRS1 in the genome of B. oleracea. Northern blot analysis revealed that BoRS1 was up‐regulated by cold, mannitol, NaCl and abscisic acid (ABA). Expressional fluctuation of time course with ABA implied a two‐step induction process. Tissue‐specific expression analysis indicated that BoRS1 was expressed in all the tested plant tissues including leaves, stems and roots. Our studies imply that BoRS1 is a new gene that is responsive to environmental stresses such as low temperature, salinity and osmotic stress.
Cold survival in freeze‐intolerant insects
Authors: Graether Steffen P. , Sykes Brian D.
Published: August 2004

Antifreeze proteins (AFPs) designate a class of proteins that are able to bind to and inhibit the growth of macromolecular ice. These proteins have been characterized from a variety of organisms. Recently, the structures of AFPs from the spruce budworm (Choristoneura fumiferana) and the yellow mealworm (Tenebrio molitor) have been determined by NMR and X‐ray crystallography. Despite nonhomologous sequences, both proteins were shown to consist of β‐helices. We review the structures and dynamics data of these two insect AFPs to bring insight into the structure–function relationship and explore their β‐helical architecture. For the spruce budworm protein, the fold is a left‐handed β‐helix with 15 residues per coil. The Tenebrio molitor protein consists of a right‐handed β‐helix with 12 residues per coil. Mutagenesis and structural studies show that the insect AFPs present a highly rigid array of threonine residues and bound water molecules that can effectively mimic the ice lattice. Comparisons of the newly determined ryegrass and carrot AFP sequences have led to models suggesting that they might also consist of β‐helices, and indicate that the β‐helix might be used as an AFP structural motif in nonfish organisms.
Phylogenetic relationships in class I of the superfamily of bacterial, fungal, and plant peroxidases
Authors: Zámocký Marcel
Published: August 2004

Molecular phylogeny among catalase–peroxidases, cytochrome c peroxidases, and ascorbate peroxidases was analysed. Sixty representative sequences covering all known subgroups of class I of the superfamily of bacterial, fungal, and plant heme peroxidases were selected. Each sequence analysed contained the typical peroxidase motifs evolved to bind effectively the prosthetic heme group, enabling peroxidatic activity. The N‐terminal and C‐terminal domains of catalase–peroxidases matching the ancestral tandem gene duplication event were treated separately in the phylogenetic analysis to reveal their specific evolutionary history. The inferred unrooted phylogenetic tree obtained by three different methods revealed the existence of four clearly separated clades (C‐terminal and N‐terminal domains of catalase–peroxidases, ascorbate peroxidases, and cytochrome c peroxidases) which were segregated early in the evolution of this superfamily. From the results, it is obvious that the duplication event in the gene for catalase–peroxidase occurred in the later phase of evolution, in which the individual specificities of the peroxidase families distinguished were already formed. Evidence is presented that class I of the heme peroxidase superfamily is spread among prokaryotes and eukaryotes, obeying the birth‐and‐death process of multigene family evolution.
Platelet factor 4 disrupts the intracellular signalling cascade induced by vascular endothelial growth factor by both KDR dependent and independent mechanisms
Authors: Sulpice Eric , Contreres Jean‐Olivier , Lacour Julie , Bryckaert Marijke , Tobelem Gerard
Published: August 2004

The mechanism by which the CXC chemokine platelet factor 4 (PF‐4) inhibits endothelial cell proliferation is unclear. The heparin‐binding domains of PF‐4 have been reported to prevent vascular endothelial growth factor 165 (VEGF165) and fibroblast growth factor 2 (FGF2) from interacting with their receptors. However, other studies have suggested that PF‐4 acts via heparin‐binding independent interactions. Here, we compared the effects of PF‐4 on the signalling events involved in the proliferation induced by VEGF165, which binds heparin, and by VEGF121, which does not. Activation of the VEGF receptor, KDR, and phospholipase Cγ (PLCγ) was unaffected in conditions in which PF‐4 inhibited VEGF121‐induced DNA synthesis. In contrast, VEGF165‐induced phosphorylation of KDR and PLCγ was partially inhibited by PF‐4. These observations are consistent with PF‐4 affecting the binding of VEGF165, but not that of VEGF121, to KDR. PF‐4 also strongly inhibited the VEGF165‐ and VEGF121‐induced mitogen‐activated protein (MAP) kinase signalling pathways comprising Raf1, MEK1/2 and ERK1/2: for VEGF165 it interacts directly or upstream from Raf1; for VEGF121, it acts downstream from PLCγ. Finally, the mechanism by which PF‐4 may inhibit the endothelial cell proliferation induced by both VEGF121 and VEGF165, involving disruption of the MAP kinase signalling pathway downstream from KDR did not seem to involve CXCR3B activation.
Relationships between structure, function and stability for pyridoxal 5′‐phosphate‐dependent starch phosphorylase from Corynebacterium callunae as revealed by reversible cofactor dissociation studies
Authors: Griessler Richard , Psik Barbara , Schwarz Alexandra , Nidetzky Bernd
Published: August 2004

Using 0.4 m imidazole citrate buffer (pH 7.5) containing 0.1 mm l‐cysteine, homodimeric starch phosphorylase from Corynebacterium calluane (CcStP) was dissociated into native‐like folded subunits concomitant with release of pyridoxal 5′‐phosphate and loss of activity. The inactivation rate of CcStP under resolution conditions at 30 °C was, respectively, four‐ and threefold reduced in two mutants, Arg234→Ala and Arg242→Ala, previously shown to cause thermostabilization of CcStP [Griessler, R., Schwarz, A., Mucha, J. & Nidetzky, B. (2003) Eur. J. Biochem.270, 2126–2136]. The proportion of original enzyme activity restored upon the reconstitution of wild‐type and mutant apo‐phosphorylases with pyridoxal 5′‐phosphate was increased up to 4.5‐fold by added phosphate. The effect on recovery of activity displayed a saturatable dependence on the phosphate concentration and results from interactions with the oxyanion that are specific to the quarternary state. Arg234→Ala and Arg242→Ala mutants showed, respectively, eight‐ and > 20‐fold decreased apparent affinities for phosphate (Kapp), compared to the wild‐type (Kapp≈ 6 mm). When reconstituted next to each other in solution, apo‐protomers of CcStP and Escherichia coli maltodextrin phosphorylase did not detectably associate to hybrid dimers, indicating that structural complementarity among the different subunits was lacking. Pyridoxal‐reconstituted CcStP was inactive but ≈ 60% and 5% of wild‐type activity could be rescued at pH 7.5 by phosphate (3 mm) and phosphite (5 mm), respectively. pH effects on catalytic rates were different for the native enzyme and pyridoxal‐phosphorylase bound to phosphate and could reflect the differences in pKa values for the cofactor 5′‐phosphate and the exogenous oxyanion.
Cdt1 and geminin are down‐regulated upon cell cycle exit and are over‐expressed in cancer‐derived cell lines
Authors: Xouri Georgia , Lygerou Zoi , Nishitani Hideo , Pachnis Vassilis , Nurse Paul , Taraviras Stavros
Published: August 2004

Licensing origins for replication upon completion of mitosis ensures genomic stability in cycling cells. Cdt1 was recently discovered as an essential licensing factor, which is inhibited by geminin. Over‐expression of Cdt1 was shown to predispose cells for malignant transformation. We show here that Cdt1 is down‐regulated at both the protein and RNA level when primary human fibroblasts exit the cell cycle into G0, and its expression is induced as cells re‐enter the cell cycle, prior to S phase onset. Cdt1's inhibitor, geminin, is similarly down‐regulated upon cell cycle exit at both the protein and RNA level, and geminin protein accumulates with a 3–6 h delay over Cdt1, following serum re‐addition. Similarly, mouse NIH3T3 cells down‐regulate Cdt1 and geminin mRNA and protein when serum starved. Our data suggest a transcriptional control over Cdt1 and geminin at the transition from quiescence to proliferation. In situ hybridization and immunohistochemistry localize Cdt1 as well as geminin to the proliferative compartment of the developing mouse gut epithelium. Cdt1 and geminin levels were compared in primary cells vs. cancer‐derived human cell lines. We show that Cdt1 is consistently over‐expressed in cancer cell lines at both the protein and RNA level, and that the Cdt1 protein accumulates to higher levels in individual cancer cells. Geminin is similarly over‐expressed in the majority of cancer cell lines tested. The relative ratios of Cdt1 and geminin differ significantly amongst cell lines. Our data establish that Cdt1 and geminin are regulated at cell cycle exit, and suggest that the mechanisms controlling Cdt1 and geminin levels may be altered in cancer cells.
Differential interactions of decorin and decorin mutants with type I and type VI collagens
Authors: Nareyeck Gordon , Seidler Daniela G. , Troyer David , Rauterberg Jürgen , Kresse Hans , Schönherr Elke
Published: August 2004

The small leucine‐rich proteoglycan decorin can bind via its core protein to different types of collagens such as type I and type VI. To test whether decorin can act as a bridging molecule between these collagens, the binding properties of wild‐type decorin, two full‐length decorin species with single amino acid substitutions (DCN E180K, DCN E180Q), which previously showed reduced binding to collagen type I fibrils, and a truncated form of decorin (DCN Q153) to the these collagens were investigated. In a solid phase assay dissociation constants for wild‐type decorin bound to methylated, therefore monomeric, triple helical type I collagen were in the order of 10−10 m, while dissociation constants for fibrillar type I collagen were ≈ 10−9 m. The dissociation constant for type VI was ≈ 10−7 m. Using real‐time analysis for a more detailed investigation DCN E180Q and DCN E180K exhibited lower association and higher dissociation constants to type I collagen, compared to wild‐type decorin, deviating by at least one order of magnitude. In contrast, the affinities of these mutants to type VI collagen were 10 times higher than the affinity of wild‐type decorin (KD ≈ 10−8 m). Further investigations verified that complexes of type VI collagen and decorin bound type I collagen and that the affinity of collagen type VI to type I was increased by the presence of decorin. These data show that decorin not only can regulate collagen fibril formation but that it also can act as an intermediary between type I and type VI collagen and that these two types of collagen interact via different binding sites.
Analysis of the transcarbamoylation‐dehydration reaction catalyzed by the hydrogenase maturation proteins HypF and HypE
Authors: Blokesch Melanie , Paschos Athanasios , Bauer Anette , Reissmann Stefanie , Drapal Nikola , Böck August
Published: August 2004

The hydrogenase maturation proteins HypF and HypE catalyze the synthesis of the CN ligands of the active site iron of the NiFe‐hydrogenases using carbamoylphosphate as a substrate. HypE protein from Escherichia coli was purified from a transformant overexpressing the hypE gene from a plasmid. Purified HypE in gel filtration experiments behaves predominantly as a monomer. It does not contain statistically significant amounts of metals or of cofactors absorbing in the UV and visible light range. The protein displays low intrinsic ATPase activity with ADP and phosphate as the products, the apparent Km being 25 µm and the kcat 1.7 × 10−3 s−1. Removal of the C‐terminal cysteine residue of HypE which accepts the carbamoyl moiety from HypF affected the Km (47 µm) but not significantly the kcat (2.1 × 10−3 s−1). During the carbamoyltransfer reaction, HypE and HypF enter a complex which is rather tight at stoichiometric ratios of the two proteins. A mutant HypE variant was generated by amino acid replacements in the nucleoside triphosphate binding region, which showed no intrinsic ATPase activity. The variant was active as an acceptor in the transcarbamoylation reaction but did not dehydrate the thiocarboxamide to the thiocyanate. The results obtained with the HypE variants and also with mutant HypF forms are integrated to explain the complex reaction pattern of protein HypF.
ROLE OF CONTRACTION‐INDUCED INJURY IN THE MECHANISMS OF MUSCLE DAMAGE IN MUSCULAR DYSTROPHY
Authors: Lynch Gordon S
Published: August 2004

1. Duchenne muscular dystrophy (DMD) is a severe disease of skeletal muscle, characterized by an X‐linked recessive inheritance and a lack of dystrophin in muscle fibres. It is associated with progressive and severe wasting and weakness of nearly all muscles and premature death by cardiorespiratory failure.

2. Studies investigating the susceptibility of dystrophic skeletal muscles to contraction‐mediated damage, especially after lengthening actions where activated muscles are stretched forcibly, have concluded that dystrophin may confer protection to muscle fibres by providing a mechanical link between the contractile apparatus and the plasma membrane. In the absence of dystrophin, there is disruption to normal force transmission and greater stress placed upon myofibrillar and membrane proteins, leading to muscle damage.

3. Contraction protocols (involving activation and stretch of isolated muscles or muscle fibres) have been developed to assess the relative susceptibility of dystrophic (and otherwise healthy) muscles to contraction‐induced injury. These protocols have been used successfully to determine the relative efficacy of different (gene, cell or pharmacological) interventions designed to ameliorate or cure the dystrophic pathology. More research is needed to develop specific ‘contraction assays’ that will assist in the evaluation of the clinical significance of different therapeutic strategies for muscular dystrophy.
STRETCH‐ACTIVATED CHANNELS IN STRETCH‐INDUCED MUSCLE DAMAGE: ROLE IN MUSCULAR DYSTROPHY
Authors: Yeung Ella W , Allen David G
Published: August 2004

1. Stretch‐induced muscle injury results in the damage that causes reduced force and increased membrane permeability. This muscle damage is caused, in part, by ionic entry through stretch‐activated channels and blocking these channels with Gd3+ or streptomycin reduces the force deficit associated with damage.

2. Dystrophin‐deficient muscles are more susceptible to stretch‐induced muscle injury and the recovery from injury can be incomplete. We have found that Na+ entry associated with stretch‐induced injury is enhanced in dystrophin‐deficient muscles and that blockers of stretch‐activated channels are capable of preventing ionic entry and reducing muscle damage.

3. A model is presented that proposes links between stretch‐induced injury, opening of stretch‐activated channels, increased levels of intracellular ions and various forms of muscle damage. Although changes in Na+ accompany stretch‐induced muscle injury, we believe that changes in Ca2+ probably have a more central role in the damage process.
IDENTIFYING ATHLETES AT RISK OF HAMSTRING STRAINS AND HOW TO PROTECT THEM
Authors: Proske U , Morgan DL , Brockett CL , Percival P
Published: August 2004

1. One common soft‐tissue injury in sports involving sprinting and kicking a ball is the hamstring strain. Strain injuries often occur while the contracting muscle is lengthened, an eccentric contraction. We have proposed that the microscopic damage to muscle fibres that routinely occurs after a period of unaccustomed eccentric exercise can lead to a more severe strain injury.

2. An indicator of susceptibility for the damage from eccentric exercise is the optimum angle for torque. When this is at a short muscle length, the muscle is more prone to eccentric damage. It is known that subjects most at risk of a hamstring strain have a previous history of hamstring strains. By means of isokinetic dynamometry, we have measured the optimum angle for torque for nine athletes with a history of unilateral hamstring strains. We also measured optimum angles for 18 athletes with no previous history of strain injuries. It was found that mean optimum angle in the previously injured muscles was at a significantly shorter length than for the uninjured muscles of the other leg and for muscles of both legs in the uninjured group. This result suggests that previously injured muscles are more prone to eccentric damage and, therefore, according to our hypothesis, more prone to strain injuries than uninjured muscles.

3. After a period of unaccustomed eccentric exercise, if the exercise is repeated 1 week later, there is much less evidence of damage because the muscle has undergone an adaptation process that protects it against further damage. We propose that for athletes considered at risk of a hamstring strain, as indicated by the optimum angle for torque, a regular programme of mild eccentric exercise should be undertaken. This approach seems to work because evidence from a group of athletes who have implemented such a programme shows a significant reduction in the incidence of hamstring strains.
POPPING SARCOMERE HYPOTHESIS EXPLAINS STRETCH‐INDUCED MUSCLE DAMAGE
Authors: Morgan David L , Proske Uwe
Published: August 2004

1. Exercise that involves stretching a muscle while active cause microscopic areas of damage, delayed onset muscle soreness and adaptation to withstand subsequent similar exercise.

2. Longer muscle lengths are associated with greater damage and recent animal experiments show that it is the length relative to optimum that determines the damage.

3. In humans, walking down stairs, taking two at a time, increases the length of the muscle during the lengthening and increases the delayed onset muscle soreness.

4. The observed pattern of damage is consistent with explanations based on sarcomere length instabilities.

5. The pattern of adaptation is consistent with the number of sarcomeres in series in a muscle being modulated by exercise, especially the range of muscle lengths over which eccentric exercise regularly occurs.
IDENTIFICATION OF A ZEBRAFISH MODEL OF MUSCULAR DYSTROPHY
Authors: Bassett David , Currie Peter D
Published: August 2004

1. Large‐scale mutagenic screens of the zebrafish genome have identified a number of different classes of mutations that disrupt skeletal muscle formation. Of particular interest and relevance to human health is a class of recessive lethal mutations in which muscle differentiation occurs normally, but is followed by tissue‐specific degeneration reminiscent of human muscular dystrophies.

2. We have shown that one member of this class of mutations, sapje (sap), results from mutations within the zebrafish orthologue of the human Duchenne muscular dystrophy (DMD) gene. Mutations in this locus cause Duchenne or Becker muscular dystrophies in human patients and are thought to result in a dystrophic pathology by disrupting the link between the actin cytoskeleton and the extracellular matrix in skeletal muscle cells.

3. We have found that the progressive muscle degeneration phenotype of sapje‐mutant zebrafish embryos is caused by the failure of somitic muscle attachments at the embryonic myotendinous junction (MTJ).

4. Although a role for dystrophin at the MTJ has been postulated previously and MTJ structural abnormalities have been identified in the dystrophin‐deficient mdx mouse model, in vivo evidence of pathology based on muscle attachment failure is thus far lacking. Therefore, the sapjre mutation may provide a model for a novel pathological mechanism of Duchenne muscular dystrophy and other muscle diseases. In the present review, we discuss this finding in light of previously postulated models of dystrophin function.
FUNCTIONAL BIOLOGY OF THE PRIMATE FETAL ADRENAL GLAND: ADVANCES IN TECHNOLOGY PROVIDE NEW INSIGHT
Authors: Coulter Catherine L
Published: August 2004

1. The main aim of the present review is to summarize recent experimental data from human and non‐human primate models that have identified factors essential for adrenal development and other factors that may determine the regulation of the specific structural organization and function of the adrenal gland.

2. The fetal adrenal cortex has two morphologically distinct zones, with the outer definitive zone being comprised of tightly packed small cells, which appear to be steroidogenically quiescent until late gestation, and the inner fetal zone, which appears to be steroidogenically active throughout gestation.

3. In the primate fetus, growth of the adrenal gland involves hyperplasia, hypertrophy, migration and senescence. Cells appear to proliferate in the external portion of the definitive zone and then move centripetally and become non‐proliferative in the fetal zone, where they acquire their steroidogenic capacities.

4. A variety of new technologies has been used to identify zonal‐specific markers of the cortical zones within the developing human fetal adrenal gland. On microarray, 67 transcripts showed a minimum of a 2.5‐fold difference between the fetal and adult adrenal gland. The vast majority of these genes had not been studied in relation to adrenal gland development or function. In combination with techniques such as laser capture microdissection, which has allowed the isolation of fairly pure zone‐specific cell populations from the human fetal adrenal cortex, we can begin to unravel the complex interactions regulating adrenal growth and functional differentiation.
TRANSITORY REDUCTION IN ANGIOTENSIN AT2 RECEPTOR EXPRESSION LEVELS IN POSTINFARCT REMODELLING IN RAT MYOCARDIUM
Authors: Lax Clare J , Domenighetti Andrea A , Pavia Jillian M , Di Nicolantonio Robert , Curl Claire L , Morris Margaret J , Delbridge Lea MD
Published: August 2004

1. Myocardial infarction (MI) poses a significant risk for sudden cardiac death. The effectiveness of angiotensin‐converting enzyme (ACE) inhibitors and AT1 receptor blockade in attenuating unfavourable post‐MI outcomes indicates an important role for angiotensin (Ang) II signalling in the post‐MI remodelling process.

2. AT1 and AT2 receptor expression is known to be altered during the early postinjury period and at the later failure stage in the infarcted heart. The aim of the present investigation was to characterize AngII receptor expression shifts in the intermediate, adaptive phases of post‐MI hypertrophic remodelling.

3. The present study investigated relative cardiac AT1 and AT2 receptor expression levels using semiquantitative reverse transcription–polymerase chain reaction (GAPDH normalized) in rats at 4 and 20 weeks after ligation of the left anterior descending coronary artery.

4. Heart weight and normalized heart weight were significantly higher in the MI group than in the sham group 4 weeks post‐MI, with significant hypertrophy of the left ventricle, left atrium and right ventricle in MI rats. At 20 weeks post‐MI, left ventricular hypertrophy remained significant, whereas the mass of the other cardiac tissues was not different to that of sham controls.

5. AT2 receptor expression was markedly reduced in both the non‐infarct and infarcted areas of the left ventricular wall in the MI group compared with the sham‐operated group 4 weeks after surgery. Expression levels were reduced to 8 and 13% of sham values in the viable and scar tissue regions, respectively. By 20 weeks post‐MI, there was no evidence of AT2 receptor expression suppression in the left ventricle. No significant relative changes in AT1 receptor mRNA levels were observed at either 4 or 20 weeks post‐MI.

6. The present study demonstrates, for the first time, a selective downregulation of left ventricular AT2 receptor expression in the intermediate phase of post‐MI ventricular remodelling in the rat. This downregulation may provide an enhanced AT1 receptor‐mediated compensatory progrowth signal in the early adaptive post‐MI growth phase. A more detailed understanding of the time‐course of differential AT1 and AT2 receptor expression regulation post‐MI may potentially identify an optimal window for targeted pharmacological intervention in the treatment of MI.
INCREASE OF ANTI‐OXIDATION BY EXERCISE IN THE LIVER OF OBESE ZUCKER RATS
Authors: Chang Shih‐Pei , Chen Yu‐Hsuan , Chang Weng‐Cheng , Liu I‐Min , Cheng Juei‐Tang
Published: August 2004

1. The effects of endurance training on the anti‐oxidant status in diabetes were studied using obese Zucker rats.

2. We used a moderate exercise programme consisting of treadmill running at 20 m/min and 0% incline for 1 h/day, 7 days/week, for 8 weeks. At the end of the experimental period, changes in hepatic anti‐oxidant enzymes in terms of protein content and mRNA levels were detected using western blotting analysis and northern blotting analysis, respectively. In addition, anti‐oxidant enzyme activity was determined.

2. A significant reduction in mRNA levels and the protein content of hepatic Mn‐superoxide dismutase (SOD) and glutathione peroxidase (GPx) were observed in non‐exercise obese groups, but the mRNA and protein levels of these enzymes were markedly increased after exercise training. In addition, exercise training reversed the decreased enzyme activities of Mn‐SOD and GPx in obese Zucker rats.

3. The diabetes‐related lowering of the glutathione (GSH) concentration was elevated in exercised obese Zucker rats, indicating a marked effect of regular moderate exercise on the endogenous anti‐oxidant system.

4. There were no marked changes in hepatic Cu/Zn‐SOD in terms of mRNA levels, protein content and activity in sedentary obese Zucker rats compared with their lean littermates. Endurance training did not modify the gene expression and activity of hepatic Cu/Zn‐SOD.

5. The results of the present study suggest that regular moderate exercise could improve the anti‐oxidant defence function of Mn‐SOD, GPx and GSH in obese Zucker rats.
PROTECTIVE EFFECT OF U74500A ON PHORBOL MYRISTATE ACETATE–INDUCED ACUTE LUNG INJURY
Authors: Chu Shi‐Jye , Chang Deh‐Ming , Wang David , Lin Hen‐I , Lin Shih‐Hua , Hsu Kang
Published: August 2004

1. The present study was designed to determine whether U74500A could ameliorate acute lung injury (ALI) induced by phorbol myristate acetate (PMA) in our rat isolated lung model compared with any amelioration induced by dimethylthiourea (DMTU), superoxide dismutase (SOD) and catalase.

2. Acute lung injury was induced successfully by PMA during 60 min of observation. At 2 µg/kg, PMA elicited a significant increase in microvascular permeability (measured using the capillary filtration coefficient Kfc), lung weight gain, the lung weight/bodyweight ratio, pulmonary arterial pressure and protein concentration of the bronchoalveolar lavage fluid.

3. Pretreatment with 1.5 mg/kg U74500A significantly attenuated ALI; there was no significant increase in any parameters measured, except for pulmonary arterial pressure. The protective effect of U74500A was approximately the same as that of 600 mg/kg DMTU. However, 6000 U/kg SOD, 50 000 U/kg catalase and 6000 U/kg SOD + 50 000 U/kg catalase had no protective effect.

4. These experimental data suggest that U74500A significantly ameliorates ALI induced by PMA in rats.
Serum lipid profile in obese children in China
Authors: Li Shilian , Liu Xiaolan , Okada Tomoo , Iwata Fujihiko , Hara Mitsuhiko , Harada Kensuke
Published: August 2004

Abstract
Background
: The aim of the present study was to examine the serum lipid profile in obese Chinese children, their serum lipid and apolipoprotein A‐I (apoA‐I) and B (apoB) levels were examined.

Methods
: The subjects were 153 patients (109 male and 44 female) aged 4−16 years with obesity, who attended the outpatient clinic of Beijing Children's Hospital. Percentage bodyweight (%BW) ([(bodyweight − standard weight)/standard weight]× 100) were obtained. Skinfold thickness and hip and waist circumference were measured. Percentage body fat (%BF) was estimated by bioelectrical impedance analyzer. Serum total cholesterol (TC), high density lipoprotein cholesterol (HDLC), triglyceride (TG), apoA‐I and apoB levels were also measured.

Results
: TC showed an acceptable level in 86.8% of obese children. The prevalence of high TC levels (3.3%) or high LDLC levels (6.0%) was rather low. The HDLC level was reduced in 31.3% of obese children. Anthropometric variables had no linear relationship to TC, HDLC, TG, LDLC, apoA‐I or apoB, but in the older age group (over 10 years old) %BW and %BF showed a weak correlation with HDLC (r = −0.202, r = −0.211, respectively).

Conclusion
: In obese Chinese children, HDLC as well as TC levels should be examined in order to assess coronary risk.
Diagnostic role of 99mTc hexamethyl‐propyleneamine oxime brain single photon emission computed tomography in Sydenham's chorea
Authors: Demirören Kaan , Tastekin Güngör , Oran Bülent
Published: August 2004

Abstract
Background
: The objective of this study was to determine whether technetium‐99m hexamethyl‐propyleneamine oxime (HMPAO) brain single photon emission computed tomography (SPECT) imaging is capable of detecting perfusional abnormalities in Sydenham's chorea (SC) patients and contributing to diagnosis of SC.

Methods
: In this study, 17 SC patients were evaluated. HMPAO SPECT was performed on all patients at the acute phase and six of them at the recovery phase. Magnetic resonance imaging (MRI) of the brain was performed to 13 patients. SPECT images of basal ganglia and thalamus were evaluated both visually and by measuring the radioactivity uptakes. Ten subjects constituted the control group.

Results
: HMPAO SPECT was visually evaluated as indicating hyperperfusion in the basal ganglia and thalamus in 16 patients, and evaluated as normal in one patient at the acute phase. The radioactivity uptakes of basal ganglia and thalamus of the patients at the acute phase were found statistically higher than those of the patients at the recovery phase, and also higher than those of the control group (P < 0.05). A significant difference between the radioactivity uptake of the patients at the recovery phase and those of the control group was not found (P > 0.05). Only one patient did not show any abnormality in both acute and recovery phases. MRI study did not show any abnormality in the basal ganglia and thalamus.

Conclusion
: It is suggested that brain SPECT can contribute to the diagnosis of SC as an objective tool. Resolving of the hyperperfusion at the recovery phase provides further support for the diagnosis of SC.
Risk of hypervitaminosis D from prolonged feeding of high vitamin D premature infant formula
Authors: Nako Yasushi , Tomomasa Takeshi , Morikawa Akihiro
Published: August 2004

Abstract
Background
: Most premature infant formulas marketed in Japan have high vitamin D content. Potential for vitamin D intoxication was assessed in premature infants with prolonged feeding of such a premature formula vitamin D content, 2700 IU/L.

Methods
: Serum vitamin D, calcium and phosphorus, and urinary calcium, were measured in 12 very premature infants fed premature infant formula, regular formula (vitamin D content; 460 IU/L), and/or mother's milk.

Results
: Concentrations of 25(OH)D in sera associated with sole feeding of premature infant formula (n = 40) were significantly higher than sera corresponding to regular formula or breast milk (n = 25; 175 versus 115 nmol/L, P <0.0001). No sample showed a serum 25(OH)D concentration below 25 nmol/L. Of 65 samples, 49 (75.4%) showed 25(OH)D concentrations exceeding 100 nmol/L, but serum calcium and phosphorus concentrations were normal. Unexpectedly, urinary calcium correlated negatively with serum 25(OH)D.

Conclusion
: In prolonged feeding of premature infant formula with high vitamin D, it was concluded that it could cause a high blood concentration of vitamin D in premature infants, and also that in these infants urine calcium is not a reliable indicator of excessive vitamin D intake.
Primary nephrotic syndrome during childhood in Turkey
Authors: Özkaya Nuray , Çakar Nilgün , Ekim Mesiha , Kara Nazli , Akkök Nermin , Yalçinkaya Fatos
Published: August 2004

Abstract
Background
: Minimal change nephrotic syndrome (MCNS) is the most common cause of primary nephrotic syndrome (NS) during childhood. However, recent studies from different countries have reported an increasing incidence of focal segmental glomerulosclerosis (FSGS) in children.

Methods
: This is a retrospective study in which 392 Turkish children who were diagnosed with NS during the last 10 years and were followed for at least 2 years, were evaluated. Mean age of the study group was 4.6 ± 3.4 years (range 0.9−16 years) and 232 were male and 160 were female.

Results
: In total, 280 patients were diagnosed as MCNS with their initial presentations, laboratory features, and clinical course. Kidney biopsy was performed in the remaining 112 children according to current recommendations. The results showed that membranoproliferative glomerulonephritis (MPGN) was the most common histopathologic diagnosis, 38 (34%) of the 112 patients were found to have MPGN. The number diagnosed as FSGS was 26 (23%). A significant difference was found between the age groups for both MPGN and FSGS, the former being more common in children >6 years of age and the latter more frequent in children ≤6 years. MCNS was found in only 19% of all biopsies performed and the total incidence of MCNS (presumptive + biopsy proven) was 76%. There was no significant difference between the incidence of different histopathological subtypes before and after 1995.

Conclusion
: Minimal change nephrotic syndrome is still the most common primary NS in childhood and MPGN is found to be the most common histopathologic subtype in the present patient population who underwent biopsy.
Comparison of two methods for evaluating bone marrow metastasis of neuroblastoma: Reverse transcription‐polymerase chain reaction for tyrosine hydroxylase and magnetic resonance imaging
Authors: Takemoto Chikayo , Nishiuchi Ritsuo , Endo Chie , Oda Megumi , Seino Yoshiki
Published: August 2004

Abstract
Background
: The presence of bone marrow (BM) metastasis and circulating tumor cells in patients with neuroblastoma is a significant prognostic factor at diagnosis and might antedate detection of a relapse by other diagnostic studies. In this study, the clinical value of reverse transcription‐polymerase chain reaction (RT‐PCR) to amplify mRNA for tyrosine hydroxylase (TH) and magnetic resonance imaging (MRI) during the clinical course of patients with advanced neuroblastoma, was evaluated.

Methods
: Four patients with Stage 1, 4 or 4S neuroblastoma, were studied. BM and peripheral blood (PB), including peripheral blood stem cell (PBSC), samples were examined for TH mRNA using RT‐PCR. Concurrently, MRI detection of BM metastasis was used.

Results
: In all cases, except one that had no evidence of BM invasion, TH mRNA in BM and PB at diagnosis were positive, and TH mRNA at diagnosis disappeared after chemotherapy. In two cases, although involvement in the neurocentrum BM was detected by MRI, TH mRNA in the iliac crest BM was negative. The pathological area still remained on MRI after intensive therapy.

Conclusion
: RT‐PCR for TH mRNA might be the most sensitive method for the detection of occult neuroblastoma cells in BM and PB. However, because invasion of the BM by neuroblastoma may have a focal distribution, sampling errors can occur. Therefore, not only RT‐PCR but also MRI, need to be used to rule out marrow involvement, especially at diagnosis and BM relapse.
Studies on cerebrospinal fluid ionized calcium and magnesium concentrations in convulsive children
Authors: Miyamoto Yusaku , Yamamoto Hitoshi , Murakami Hiroshi , Kamiyama Noriko , Fukuda Miho
Published: August 2004

Abstract
Background
: The concentrations of ionized calcium (iCa) and ionized magnesium (iMg) were measured in the cerebrospinal fluid (CSF) of convulsive and non‐convulsive children, to investigate the relationship between seizure manifestation and CSF iCa and iMg concentrations. Standard concentrations of CSF iCa and iMg were also established.

Methods
: CSF samples from 23 patients, ages 0−15 years, with various forms of seizures and 26 age‐matched non‐convulsive children were collected by lumbar puncture. CSF was obtained anaerobically and the concentrations of CSF iCa and iMg were measured with an electolyte analyzer (Stat Profile Ultra M1, NOVA, USA) immediately after the lumbar puncture.

Results
: The concentrations of CSF iCa were significantly higher in non‐convulsive children younger than 11 months old compared with children older than 12 months. The concentrations of CSF iMg in non‐convulsive children did not differ significantly with aging. The concentrations of CSF iCa in convulsive children did not differ significantly from the concentrations of non‐convulsive children. The concentrations of CSF iMg in convulsive children were significantly lower than in non‐convulsive children.

Conclusion
: These results suggest that seizure manifestation is related to age‐dependent changes in iCa and decreased iMg in the developing brain.
Guidelines for treatment of ulcerative colitis in children
Authors: Tomomasa Takeshi , Kobayashi Akio , Ushijima Kousuke , Uchida Keiichi , Kagimoto Seiichi , Shimizu Toshiaki , Tajiri Hitoshi , Tahara Takuhiro , Yoden Atushi ,   Working Group of the Japanese Society for Pediatric Gastroenterology, Hepatology and Nutrition
Published: August 2004

Abstract This paper introduces the guidelines for treatment of ulcerative colitis in children, created by the working group of the Japanese Society for Pediatric Gastroenterology, Hepatology and Nutrition (Chair: Yuichiro Yamashiro) and the Japanese Society for Pediatric Inflammatory Bowel Disease (IBD) (Chair: Akio Kobayashi).

The ideas of the working group, with regard to the fundamental differences in medical treatment between children and adults, included: (1) for children, intensive medical treatment including appropriate systemic management is important during the acute phase of illness. (2) Treatment with steriods, which can cause growth disturbances, should not be continued for long periods of time. (3) Pulsed steriod therapy, selective removal of blood cells, and intravenous infusion of cyclosporin should be included in the therapeutic option for severe and fluminant cases.