bluuebunny/crossref_metadata_2025 huggingface dataset:
Conversion of short‐chain ceramides to short‐chain ceramide GM3 in B16 melanoma cells
Authors: Komori Hironobu , Ito Makoto
Published: May 2003

We report that short‐chain ceramide (Cer), C2‐ and C6‐Cer, were immediately glycosylated and finally converted to short‐chain Cer GM3 in B16 melanoma cells. By addition of either C2‐ or C6‐Cer to a cell culture of B16 melanoma in the presence of [14C]Gal, the radiolabeled precursor, was incorporated into each of two novel glycosphingolipids (GSLs) within 30 min along with synthesis of normal GSLs. These novel GSLs were identified as C2‐, C6‐Cer cerebrosides and C2‐, C6‐Cer GM3, respectively. In comparison with C2‐Cer, C6‐Cer was found to be much more efficiently converted to the GSLs, whereas no glycosylated sphingosine was detectable when it was added in place of short‐chain Cer.
Quantification of DNA damage and repair in amino acid auxotrophs and UV‐sensitive mutants of Aspergillus nidulans using an ELISA
Authors: Donnelly E. , Barnett Y.A. , McCullough W.
Published: May 2003

An ELISA used to investigate DNA repair in mammalian cells has been adapted to investigate mutagen‐induced DNA damage and repair in protoplasts of Aspergillus nidulans. The assay shows a reduced rate of repair of DNA damage in methionine and arginine auxotrophs (methG and argB), which were shown previously to be hypersensitive to UV radiation and chemical mutagens. The assay also showed a considerably reduced ability to repair mutagen‐induced damage in the uv‐sensitive mutants uvsB and uvsH. The increased sensitivity of amino acids auxotrophs to mutagens is, therefore, correlated with a reduced capacity to repair mutagen‐induced DNA damage.
A mutation affecting carbon catabolite repression suppresses growth defects in pyruvate carboxylase mutants from Saccharomyces cerevisiae
Authors: Blázquez Miguel A. , Gamo Francisco-Javier , Gancedo Carlos
Published: May 2003

Yeasts with disruptions in the genes PYC1 and PYC2 encoding the isoenzymes of pyruvate carboxylase cannot grow in a glucose‐ammonium medium (Stucka et al. (1991) Mol. Gen. Genet. 229, 307–315). We have isolated a dominant mutation, BPC1‐1, that allows growth in this medium of yeasts with interrupted PYC1 and PYC2 genes. The BPC1‐1 mutation abolishes catabolite repression of a series of genes and allows expression of the enzymes of the glyoxylate cycle during growth in glucose. A functional glyoxylate cyle is necessary for suppression as a disruption of gene ICL1 encoding isocitrate lyase abolished the phenotypic effect of BPC1‐1 on growth in glucose‐ammonium. Concurrent expression from constitutive promoters of genes ICL1 and MLS1 (encoding malate synthase) also suppressed the growth phenotype of pyc1 pyc2 mutants. The mutation BPC1‐1 is either allelic or closely linked to the mutation DGT1‐1.
Gelatinase A possesses a β‐secretase‐like activity in cleaving the amyloid protein precursor of Alzheimer's disease
Authors: LePage Rex N. , Fosang Amanda J. , Fuller Stephanie J. , Murphy Gillian , Evin Geneviève , Beyreuther Konrad , Masters Colin L. , Small David H.
Published: May 2003

The ability of the 72 kDa gelatinase A to cleave the amyloid protein precursor (APP) was investigated. HeLa cells were transfected with an APP695 plasmid. The cells were incubated with gelatinase A, which cleaved the 110 kDa cell‐surface APP, releasing a 100 kDa form of the protein. A peptide homologous to the β‐secretase site was cleaved by gelatinase A adjacent to a glutamate residue at position −3 (βA4 numbering system). A peptide homologous to the α‐secretase site was not cleaved. The results demonstrate that 72 kDa gelatinase A is not an α‐secretase, but that it may have a β‐secretase activity.
Photoaffinity labelling of the mitochondrial uncoupling protein by [3H]azido fatty acid affects the anion channel
Authors: Růžička Michal , Borecký Jiří , Hanuš Jan , Ježek Petr
Published: May 2003

Brown adipose tissue (BAT) mitochondria were incubated with the azido derivative of fatty acid (hexadecanoic) containing four tritium atoms, [3H]AzHA, and among all mitochondrial proteins only a few proteins were photolabelled after irradiation with UV. It suggests the existence of specific fatty acid binding sites on mitochondrial proteins. It was also possible to label with [3H]AzHA the isolated uncoupling protein (UcP) of BAT mitochondria with a low stoichiometry — lower than one AzHA per dimeric UcP. These results together with the observed competition (i.e. prevention of photolabelling) of various UcP anionic substrates with [3H]AzHA and its dodecanoic acid analogue, suggest the existence of the specific fatty acid binding site on UcP identical with the anion channel or anion translocating site.
Mutants of EF‐Tu defective in binding aminoacyl‐tRNA
Authors: Abdulkarim Farhad , Ehrenberg Måns , Hughes Diarmaid
Published: May 2003

Five single amino acid substitution variants of EF‐Tu from Salmonella typhimurium were tested for their ability to promote poly(U)‐translation in vitro. The substitutions are Leu120Gln, Gln124Arg and Tyr160 (Asp or Asn or Cys). They were selected by their kirromycin resistant phenotypes and all substitutions are in domain I at the interface between domains I and III of the EF‐Tu·GTP configuration. The different EF‐Tu variants exhibit a spectrum of phenotypes. First, k

cat
/K

M
for the interaction between ternary complex and the programmed ribosome is apparently reduced by the substitutions Leu120Gln, Gln124 Arg and Tyr160Cys. Second, this reduction is caused by a defect in the interaction between these EF‐Tu variants and aminoacyl‐tRNA during translation. Third, in four cases out of five the affinity of the complex between EF‐Tu·GTP and aminoacyl‐tRNA is significantly decreased. The most drastic reduction is observed for the Gln124Arg change, where the association constant is 30‐fold lower than in the wild‐type case. Fourth, missense errors are increased as well as decreased by the different amino acid substitutions. Finally, the dissociation rate constant (k

d
) for the release of GDP from EF‐Tu is increased 6‐fold by the Tyr160Cys substitution, but remains unchanged in the four other cases. These results show that the formation of ternary complex is sensitive to many different alterations in the domain I–III interface of EF‐Tu.
Cloning of rat 92‐kDa type IV collagenase and expression of an active recombinant catalytic domain
Authors: Xia Yiyang , Garcia Gabriela , Chen Shizhong , Wilson Curtis B. , Feng Lili
Published: May 2003

A full‐length cDNA for rat 92‐kDa type IV collagenase was isolated and sequenced. RNase protection assay revealed tissue specific differential expression of the 92‐kDa type IV collagenase in the rat during development. Natural and modified forms of the 92‐kDa type IV collagenase were expressed. One active protein, 92‐CD, contained only the putative catalytic domain. Large quantities of the 92‐CD were expressed in Escherichia coli, extracted from inclusion bodies, purified, and refolded to an active form. This recombinant protein was able to cleave denatured and native collagen and was inactivated by known MMP inhibitors.
Non‐histone protein 1 (NHP1) is a member of the Ku protein family which is upregulated in differentiating mouse myoblasts and human promyelocytes
Authors: Oderwald Harald , Hughes Melya J. , Jost Jean-Pierre
Published: May 2003

We have previously purified and characterized a ubiquitous non‐histone protein (NHP1) which has a high affinity (K
d 10−11 M) for different avian vitellogenin gene sequences containing CpGs (Hughes et al. (1989) Biochemistry 28, 9137–9142; Hughes and Jost (1989) Nucleic Acids Res. 17, 8511–8520). Here we show by microsequencing that the peptides derived from the purified p75 and p85 subunits of NHP1 from HeLa cells have between 64 and 100% identity with the human Ku autoantigen. During the differentiation of human HL‐60 promyelocytes there is an increase in the amount of p85 subunit protein whereas the level of the p75 subunit is unchanged. In differentiating mouse G8 myoblasts there is, however, an upregulation of both the p75 and p85 subunits and of the p85 mRNA. An inhibition of mouse myoblast differentiation by either cAMP, 3‐aminobenzamide or sodium butyrate abolishes the upregulation of the p85 subunit. In G8 myoblasts chemical, or physical stress by UV light or X‐rays does not upregulate the level of the p85 subunit. The possible involvement of NHP1 in the active demethylation of bifilarly methylated DNA will be discussed.
Technology choice with stochastic demands and dynamic capacity allocation: A two‐product analysis
Authors: Li Shanling , Tirupati Devanath
Published: May 2003

In this paper we examine issues related to technology choice and capacity expansion in an environment characterized by two product families with stochastic demands. The motivation for our work comes from developments in modern technologies such as FMS and CIM that provide considerable operational flexibility. In this paper we focus on the tradeoffs between product mix flexibility of integrated technologies and dedicated facilities designed to produce efficiently a limited range of products. We present an investment model to determine optimal mix of technology and capacity choices in order to satisfy specified service levels. Based on the detailed analysis of a special case with uniform distributions, we develop a solution procedure that is amenable for extension to other demand distributions. The scope of this approach for deriving managerial insights is illustrated with computational results.
Optimal dynamic policies for product and process innovation
Authors: Bayus Barry L.
Published: May 2003

Relatively few studies have analytically examined incremental product and process R & D activities after a product is in the marketplace. In this paper, new product demand is modeled as a dynamic function of price and incremental product innovation, while process improvements influence costs. Optimal price, and product and process R & D expenditure patterns are studied analytically and with numerical methods. Results are partially consistent with existing hypotheses in the literature and, at the same time, some new insights are obtained. The main conclusion is that the rates of incremental product and process innovation over the product life cycle are a function of the interdependence between product and process improvements. Importantly, empirical innovation patterns matching each of the derived patterns have been reported by other researchers.
Current production targets and strategic decisions by corporate managers
Authors: Hughes John S. , Thevaranjan Alex
Published: May 2003

This article considers the potential role of current production targets in providing corporate managers with incentives for allocating their efforts toward operational and strategic decisions. Operational decisions relate to current production, while strategic decisions affect both current production and future profitability. A moral hazard exists to the extent that manager effort allocations are not observable. Of interest is the design of compensation contracts which efficiently resolve that hazard. Attention is mainly focused on distortions in current production away from targets which would be optimal if manager effort allocations were observable. The principal insight is that an increase in current production targets may, paradoxically, be motivated by a desire to induce a greater allocation of effort to strategic decisions.
Risk aversion, generalized correlation and investment in manufacturing capacities
Authors: Callen Jeffrey L. , Sarath Bharat
Published: May 2003

This study analyzes the relationship between product demand correlation and risk on the investment in dedicated and flexible manufacturing capacities. It is proved that for a risk averse (or risk neutral) decision‐maker, increased generalized correlation between output demands reduces the values of both dedicated and flexible manufacturing investments for all multivariate distributions. It is shown that no such monotonic relationship generally exists for the capacities themselves because of an economic tradeoff between risk and return. It is also proved that increased generalized correlation reduces the value of flexible capacity relative to dedicated capacity for the risk‐neutral decision maker. However, contrary to the extant literature, flexible capacity is still shown to be potentially valuable even if product demands are perfectly positively correlated. Finally, it is shown that increases in the risk of product demand, holding correlation (of product demand) constant, reduces the value of the investment in manufacturing capacities when output demands are either jointly normal or independent.
Institutional research productivity in production and operations management
Authors: Malhotra Manoj K. , Kher Hemant V.
Published: May 2003

This study investigates the research contributions of academic and other institutions in the area of Productions and Operations Management (POM) over the past 15 years. Similar studies have also been previously conducted in other functional areas of business such as Finance, Marketing, MIS and Management. Institutional productivity is assessed by counting the number of articles and number of standardized pages published in five major POM research journals during a 15 year period from 1980 to 1994. The journals selected include Management Science, Decision Sciences, Journal of Operations Management, IIE Transactions and International Journal of Production Research. A previous study had ranked these as the top 5 journals publishing high quality POM research. Results indicate that among the 50 institutions that emerged from our study as the top ranked ones, no single institution dominated the rankings across all the journals. The diversity of institutions reflected in these rankings shows that the field of POM is maturing and growing. Even though the overall research productivity has increased tremendously over the course of the past 15 years, the longitudinal analysis reveals that often there are periods of high and low productivity in the life of individual research institutions. The results of this study can be used by industrial researchers, doctoral students, and faculty members to assess the primary sources of contribution to each journal, to better guide their publication strategies, and even to help plan their careers.
Dexamethasone reverses TGF‐β‐mediated inhibition of primary rat preadipocyte differentiation
Authors: Shin Sun Mi , Kim Kun-yong , Kim Jae Kwang , Yoon Suk Ran , Choi Inpyo , Yang Young
Published: May 2003

Dexamethasone and transforming growth factor‐β (TGF‐β) show contrary effects on differentiation of adipocytes. Dexamethasone stimulates adipocyte differentiation whereas TGF‐β inhibits it. In the present study, we investigated whether dexamethasone could reverse the TGF‐β‐mediated inhibition of preadipocyte differentiation. Primary rat preadipocytes, obtained from Sprague–Dawley rats, were pretreated with dexamethasone in the presence or absence of TGF‐β, prior to the induction of differentiation. Co‐treatment of dexamethasone and TGF‐β before inducing differentiation reversed the TGF‐β‐mediated inhibition of preadipocyte differentiation. In order to elucidate the mechanism by which dexamethasone reversed the effect of TGF‐β on the inhibition of preadipocyte differentiation, the expression of CCAAT/enhancer binding protein‐α (C/EBPα) and peroxisome proliferator‐activated receptor γ (PPARγ) was examined. Dexamethasone increased C/EBPα and PPARγ expression in the absence of TGF‐β and also recovered the TGF‐β‐mediated suppression of C/EBPα expression in preadipocytes. Its effect was sustained in differentiated adipocytes as well. However, those effects were not observed in 3T3‐L1 preadipocytes or differentiated adipocytes. These results indicate that dexamethasone reverses the TGF‐β‐mediated suppression of adipocyte differentiation by regulating the expression of C/EBPα and PPARγ, which is dependent on the cellular context.
γ‐MSH increases intracellular cAMP accumulation and GnRH release in vitro and LH release in vivo
Authors: Stanley S.A. , Davies S. , Small C.J. , Gardiner J.V. , Ghatei M.A. , Smith D.M. , Bloom S.R.
Published: May 2003

The roles of the melanocortin 3 receptor (MC3‐R) and its agonist, γ2‐melanocyte‐stimulating hormone (γ2‐MSH) in the regulation of the hypothalamo‐pituitary‐gonadal (HPG) axis are poorly understood. Here we show γ2‐MSH stimulated intracellular cAMP accumulation and gonadotrophin‐releasing hormone (GnRH) secretion in the immortalised GnRH cell line GT1‐7. The MC3/4‐R antagonist Agrp blocked these actions. Reverse transcriptase polymerase chain reaction demonstrated GT1‐7 cells express MC3‐R mRNA. γ2‐MSH also stimulated GnRH release from hypothalamic explants. In vivo, γ2‐MSH administration into the medial preoptic area significantly increased plasma luteinising hormone. MC3‐R and γ2‐MSH may modulate the HPG axis.
Conserved hydrophobicity in the SH2–kinase linker is required for catalytic activity of Csk and CHK
Authors: Mikkola Esa T , Bergman Mathias
Published: May 2003

The crystal structure of full‐length Csk (C‐terminal Src kinase) molecules shows a hydrophobic interaction between the SH2–kinase linker residue Phe183 and the αC‐helix of the catalytic domain. To study the possible involvement of this contact in the regulation of the activity of Csk and CHK (Csk homologous kinase), a Csk SH2–kinase linker deletion mutant, Csk Phe183 and CHK Leu223 point mutants were analyzed. It was observed that a residue with a long hydrophobic side chain in position 183 (Csk) and 223 (CHK) is required to sustain the catalytic activity of Csk and CHK. These results suggest that Csk Phe183 and CHK Leu223 stabilize the movement of the αC‐helix of these protein tyrosine kinases.
Stimulation of Na+/Mg2+ antiport in rat erythrocytes by intracellular Cl−
Authors: Ebel H. , Günther T.
Published: May 2003

Mg2+ efflux from rat erythrocytes was measured in NaCl, NaNO3, NaSCN and Na gluconate medium. Substitution of extracellular and intracellular Cl− with the permeant anions NO3
− and SCN− reduced Mg2+ efflux via Na+/Mg2+ antiport. After substitution of extracellular Cl− with the non‐permeant anion gluconate, Mg2+ efflux was not significantly reduced. In Na gluconate medium, an influence of the changed membrane potential and intracellular pH on Mg2+ efflux could be excluded. The results indicate the existence of Cl−‐independent Na+/Mg2+ antiport and of Na+/Mg2+ antiport stimulated by intracellular Cl−. Intracellular Cl−, as determined by means of 36Cl−, was found to stimulate Na+/Mg2+ antiport through a cooperative effect according to a sigmoidal kinetics. The Hill coefficient for intracellular Cl− amounted to 1.4–1.8, indicating that two intracellular Cl− may be simultaneously active. With respect to specificity, Cl− was most effective, followed by Br−, J−, and F−. Stimulation of Na+/Mg2+ antiport by intracellular Cl− together with intracellular Mg2+ may play a role during deoxygenation of erythrocytes and in essential hypertension.
PAK interacts with NCK and MLK2 to regulate the activation of jun N‐terminal kinase
Authors: Poitras Luc , Jean Steve , Islam Nazrul , Moss Tom
Published: May 2003

The p21‐GTPase activated kinase, PAK1, and the mixed lineage kinase, MLK2, have been implicated in the activation of jun N‐terminal kinase (JNK). However, the role of PAK1 in JNK activation is still not understood. Here we show that over‐expression of the SH3‐SH2 adapter Nck ‘squelches’ JNK activation but this squelching is relieved by over‐expression of PAK1. In turn, PAK1 squelches activation of JNK by MLK2 and these kinases interact via their catalytic domains. The data suggest that PAK1 recruits MLK2 to an activated receptor via the adapter Nck, but cannot itself induce activation of the JNK cascade.
Two variants of zebrafish p100 are expressed during embryogenesis and regulated by Nodal signaling
Authors: Zhao C.T. , Shi K.H. , Su Y. , Liang L.Y. , Yan Y. , Postlethwait J. , Meng A.M.
Published: May 2003

Human p100 protein was first identified as a transcriptional coactivator of Epstein–Barr virus nuclear antigen 2, and has been shown to be a coactivator of other cellular transactivators. Its roles in development of vertebrate embryos, however, have not been reported. We have identified a zebrafish ortholog of the human p100 coactivator. The zebrafish p100 transcript is processed to two alternative variants, long and short forms, referred to as p100L and p100S, respectively. Both GFP‐p100L and GFP‐p100S fusion proteins are located in the cytoplasm of transfected culture cells and microinjected embryonic cells. Analysis of transcripts with Northern blots revealed the presence of p100L and lower amounts of p100S mRNAs from the one‐cell stage throughout the life cycle. Whole‐mount in situ hybridization shows that p100L and p100S share the same spatiotemporal expression pattern. Their zygotic expression is initially restricted to axial mesoderm precursors during gastrulation, and then spreads over other tissues during segmentation, and finally is constrained to some internal organs at day 5. We also find that Nodal signaling is essential for the zygotic expression of p100. These studies pave the way to understanding in depth the role of p100 during vertebrate embryogenesis.
Met174 side chain is the site of photoinsertion of a substance P competitive peptide antagonist photoreactive in position 8
Authors: Sachon E , Bolbach G , Lavielle S , Karoyan P , Sagan S
Published: May 2003

Numerous photoaffinity studies of the NK‐1 receptor have been carried out with peptide agonist analogues of substance P (SP). However, no information is available with regard to the domain interaction of peptide antagonists within this receptor. We describe herein the photoaffinity labelling of the SP receptor with a peptide antagonist analogue, Bapa0[(pBzl)Phe8,DPro9,MePhe10,Trp(CHO)11]SP. Photolabelling, enzymatic or chemical cleavage of the covalent complex, purification via streptavidin‐coated beads and matrix‐assisted laser desorption/ionization time of flight mass spectrometry analysis led us to show that the methyl of Met174 side chain, within the receptor's second extracellular loop, is covalently linked to the antagonist photoreactive at position 8.
Phosphoinositide 3‐kinase‐dependent activation of Rac
Authors: Welch Heidi C.E. , Coadwell W.John , Stephens Len R. , Hawkins Phillip T.
Published: May 2003

The monomeric GTPase Rac and the lipid kinase phosphoinositide 3‐kinase (PI3K) are intracellular signalling enzymes that each regulate a huge range of cellular functions. Their signalling pathways overlap. Several pathways lead from PI3K activation via the production of the lipid second messenger phosphatidylinositol (3,4,5)‐triphosphate (PtdIns(3,4,5)P3) to the activation of guanine‐nucleotide exchange factors (GEFs) that activate Rac. Vice versa, Rac can also stimulate the activation of PI3K, although the mechanism for this is unclear. We review here the evidence that links PI3K and Rac signalling pathways.
Selective inhibition of NF‐κB activation by the flavonoid hepatoprotector silymarin in HepG2
Authors: Saliou Claude , Rihn Bertrand , Cillard Josiane , Okamoto Takashi , Packer Lester
Published: May 2003

The bioflavonoid silymarin is found to potently suppress both nuclear factor kappa‐B (NF‐κB)‐DNA binding activity and its dependent gene expression induced by okadaic acid in the hepatoma cell line HepG2. Surprisingly, tumor necrosis factor‐α‐induced NF‐κB activation was not affected by silymarin, thus demonstrating a pathway‐dependent inhibition by silymarin. Many genes encoding the proteins of the hepatic acute phase response are under the control of the transcription factor NF‐κB, a key regulator in the inflammatory and immune reactions. Thus, the inhibitory effect of silymarin on NF‐κB activation could be involved in its hepatoprotective property.
Characterization of the 5′‐flanking promoter region of the rat somatostatin receptor subtype 3 gene
Authors: Glos Michael , Kreienkamp Hans-Jürgen , Hausmann Holger , Richter Dietmar
Published: May 2003

We investigated the 5′‐flanking promoter region of the rat somatostatin receptor subtype 3 (rSSTR3). Using a cDNA probe, genomic clones containing the 5′‐flanking promoter region of the rSSTR3 gene were isolated. A sequence of 5.4 kb directly upstream from the start codon was analyzed and two introns were found in the 5′ untranslated region (UTR) of the cDNA sequence. The transcriptional initiation site was determined by 5′ rapid amplification of cDNA ends (RACE), primer extension and RNase protection analysis with cerebellar RNA. Two major transcriptional initiation sites were found at position −1040 (tsp1) and −856 (tsp2) relative to the translational initiation site. Like a number of other promoters of G‐protein‐coupled receptors, the rSSTR3 gene lacks TATA and CAAT motifs and includes G+C‐rich regions. Functional analysis of the promoter region by transfecting rSSTR3 luciferase‐reporter gene constructs into rat pituitary GH3 cells and HEK 293 cells indicated that a 107‐bp region upstream of tsp2 was sufficient to drive transcription. Furthermore a 562‐bp region at position −1304 to −1865 upstream of the ATG start codon exerted a negative regulatory effect on transcriptional activity.
A new quantitative criterion to distinguish between α/β and α+β proteins (domains)
Authors: Zhang Chun-Ting , Zhang Ren
Published: May 2003

According to the statistical analysis, it is shown that the differences of the content of α‐helix and β‐strand between α/β and α+β proteins are of statistical significance. Based on the secondary structure content and the percentage of parallel or anti‐parallel strands, any mixed αβ protein can be represented by a point in a three‐dimensional prism. The distribution of the mapping points for 79 mixed αβ proteins (domains), of which 26 are class α/β and 53 are class α+β, shows that the two kinds of points are situated at distinct regions roughly. A new quantitative criterion based on the Fisher discriminant algorithm is proposed to distinguish between the α/β and α+β proteins (domains). Of the 79 proteins 77 are correctly classified (97.5%). As a stringent cross‐validation test, the jackknife test shows that of the 79 proteins 77 are correctly classified. The jackknife test accuracy is still 97.5%. These figures indicate the self‐consistence and the extrapolating effectiveness of the new quantitative criterion. Applying the new criterion to reclassify the α/β and α+β proteins (domains) in SCOP is also discussed. It is hoped that the new quantitative criterion will be useful for the development of protein classification databases.
Constitutive transport between the trans‐Golgi network and the plasma membrane according to the maturation model. A hypothesis
Authors: Mironov Alexander A , Luini Alberto , Buccione Roberto
Published: May 2003

Here we examine the application of the cisternal/carrier maturation model to describe transport of cargo proteins from the Golgi apparatus to the plasma membrane. Interpretation of the available evidence in the light of carrier maturation suggests that the transport intermediates between these stations are large pleiomorphic carriers formed by maturation of the trans‐Golgi compartment, rather than vesicles, as would be postulated by the vesicular shuttle model. Mature carriers move along microtubules towards the plasma membrane via a microtubule/(kinesin)‐based motor system. The maturation and vesicular transport models are compared in terms of consistency with the available literature.
Sulfonylureas blockade of neural and cardiac HERG channels
Authors: Rosati Barbara , Rocchetti Marcella , Zaza Antonio , Wanke Enzo
Published: May 2003

The human ether‐a‐go‐go‐related gene (herg) encodes a K+ current (I
HERG) which plays a fundamental role in heart excitability and in neurons by contributing to action potential repolarization and to spike‐frequency adaptation, respectively. In this paper we show that I
HERG, recorded in neuroblastoma cells and guinea‐pig ventricular myocytes, was reversibly inhibited by the KATP channel blocker glibenclamide (IC50=74 μM). The voltage and use dependence of glibenclamide blockade were also evaluated. Another sulfonylurea, glimepiride, had less effective results in blocking I
HERG. The findings of this study are relevant to the interpretation of glibenclamide effects on cellular electrophysiology and suggest that oral antidiabetic therapy with sulfonylureas may contribute to iatrogenic QT prolongation and related arrhythmias.
The Drosophila inhibitor of apoptosis D‐IAP1 suppresses cell death induced by the caspase drICE
Authors: Kaiser William J , Vucic Domagoj , Miller Lois K
Published: May 2003

Many members of the Inhibitor of Apoptosis (IAP) family inhibit cell death and existing data suggest at least two mechanisms of action. Drosophila IAPs (D‐IAP1 and D‐IAP2) and a baculovirus‐derived IAP, Op‐IAP, physically interact with and inhibit the anti‐apoptotic activity of Reaper, HID, and Grim, three genetically defined inducers of apoptosis in Drosophila, while human IAPs, c‐IAP1, c‐IAP2, and X‐IAP interact with a number of different proteins including specific members of the caspase family of cysteine proteases which are crucial in the execution of cell death. We have examined whether insect‐active IAPs can inhibit apoptosis induced by selected caspases, Drosophila drICE, Sf‐caspase‐1, and mammalian caspase‐3, in insect SF‐21 cells. D‐IAP1 inhibited apoptosis induced by the active forms of all three caspases tested and physically interacted with the active, but not the proform of drICE. MIHA, the mouse homolog of X‐IAP and an effective inhibitor of caspase‐3, also interacted with and blocked apoptosis induced by active drICE but was relatively ineffective in blocking Sf‐caspase‐1. Op‐IAP and D‐IAP2 were unable to inhibit effectively any of the active caspases tested and failed to interact with drICE. The Drosophila IAPs and Op‐IAP, but not MIHA, blocked HID‐initiated activation of pro‐drICE. We conclude that D‐IAP1 is capable of inhibiting the activation of drICE as well as inhibiting apoptosis induced by the active form of drICE. In contrast, D‐IAP2 and Op‐IAP are more limited in their inhibitory targets and may be limited to inhibiting the activation of caspases.
Expression of parathyroid hormone‐related peptide and insulin‐like growth factor I during rat fracture healing
Authors: Okazaki Ken , Jingushi Seiya , Ikenoue Takashi , Urabe Ken , Sakai Hiroaki , Iwamoto Yukihide
Published: May 2003

Parathyroid hormone‐related peptide (PTHrP) and insulin‐like growth factor I (IGF‐I) are both involved in the regulation of bone and cartilage metabolisms and their interaction has been reported in osteoblasts. To investigate the interaction of PTHrP and IGF‐I during fracture healing, the expression of mRNA for PTHrP and IGF‐I, and receptors for PTH/PTHrP and IGF were examined during rat femoral fracture healing using an in situ hybridization method and an immunohistochemistry method, respectively. During intramembranous ossification, PTHrP mRNA, IGF‐I mRNA and IGF receptors were detected in preosteoblasts, differentiated osteoblasts and osteocytes in the newly formed trabecular bone. PTH/PTHrP receptors were markedly detected in osteoblasts and osteocytes, but only barely so in preosteoblasts. During cartilaginous callus formation, PTHrP mRNA was expressed by mesenchymal cells and proliferating chondrocytes. PTH/PTHrP receptors were detected in proliferating chondrocytes and early hypertrophic chondrocytes. IGF‐I mRNA and IGF receptor were co‐expressed by mesenchymal cells, proliferating chondrocytes, and early hypertrophic chondrocytes. At the endochondral ossification front, osteoblasts were positive for PTHrP and IGF‐I mRNA as well as their receptors. These results suggest that IGF‐I is involved in cell proliferation or differentiation in mesenchymal cells, periosteal cells, osteoblasts and chondrocytes in an autocrine and/or paracrine fashion. Furthermore, PTHrP may be involved in primary callus formation presumably co‐operating with IGF‐I in osteoblasts and osteocytes, and by regulating chondrocyte differentiation in endochondral ossification.

© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
In vivo load sharing among the quadriceps components
Authors: Zhang Li‐Qun , Wang Guangzhi , Nuber Gordon W. , Press Joel M. , Koh Jason L.
Published: May 2003

Knee extension is always performed with coordinated contractions of multiple quadriceps muscle components: however, how the load is shared among them under normal and pathological conditions is unclear. We hypothesized that: the absolute moment generated by each quadriceps component increases with the total knee extension moment; the relative contribution and its dependence on the total knee extension moment are different for different quadriceps components; and the centrally located large vastus intermedius (VI) is favored by the central nervous system at low levels of activation. Electrical stimulation was used to activate each quadriceps component selectively in six human subjects. The relationship between the knee extension moment generated by an individual quadriceps component and the corresponding compound muscular action potential (M‐wave) over various contraction levels was established for each quadriceps component. This relationship was used to calibrate the corresponding EMG signal and determine load sharing among quadriceps components during submaximal isometric voluntary knee extension. The VI contributed the most (51.8–39.6%) and vastus medialis the least (9.5–12.2%) to knee extension moment (P < 0.05). As the knee extension moment increased, the relative contribution of the VI decreased (P = 0.017) while the relation contribution of the vastus lateralis and medialis increased (P ≤ 0.012). The absolute moment generated by each quadriceps component always increased with the total knee extension moment (P < 0.002). Our in vivo approach determined subject‐ and condition‐specific load sharing among individual muscles and showed that the central nervous system utilized the centrally located, uniarticular VI in submaximal isometric knee extension.

© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Healing of segmental bone defects with granular porous hydroxyapatite augmented with recombinant human osteogenic protein‐I or autologous bone marrow
Authors: den Boer Frank C. , Wippermann Burkhard W. , Blokhuis Taco J. , Patka Peter , Bakker Fred C. , Haarman Henk J. Th. M.
Published: May 2003

Hydroxyapatite is a synthetic bone graft, which is used for the treatment of bone defects and nonunions. However, it is a rather inert material with no or little intrinsic osteoinductive activity. Recombinant human osteogenic protein‐1 (rhOP‐1) is a very potent biological agent, that enhances osteogenesis during bone repair. Bone marrow contains mesenchymal stem cells, which are capable of new bone formation. Biosynthetic bone grafts were created by the addition of rhOP‐1 or bone marrow to granular porous hydroxyapatite. The performance of these grafts was tested in a sheep model and compared to the results of autograft, which is clinically the standard treatment of bone defects and nonunions. A 3 cm segmental bone defect was made in the tibia and fixed with an interlocking intramedullary nail. There were five treatment groups: no implant (n = 6), autograft (n = 8), hydroxyapatite alone (n = 8), hydroxyapatite loaded with rhOP‐1 (n = 8), and hydroxyapatite loaded with autologous bone marrow (n = 8). At 12 weeks, healing of the defect was evaluated with radiographs, a torsional test to failure, and histological examination of longitudinal sections through the defect. Torsional strength and stiffness of the healing tibiae were about two to three times higher for autograft and hydroxyapatite plus rhOP‐1 or bone marrow compared to hydroxyapatite alone and empty defects. The mean values of both combination groups were comparable to those of autograft. There were more unions in defects with hydroxyapatite plus rhOP‐1 than in defects with hydroxyapatite alone. Although the differences were not significant, histological examination revealed that there was more often bony bridging of the defect in both combination groups and the autograft group than in the group with hydroxyapatite alone. Healing of bone defects, treated with porous hydroxyapatite, can be enhanced by the addition of rhOP‐1 or autologous bone marrow. The results of these composite biosynthetic grafts are equivalent to those of autograft.

© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Cambium cell stimulation from surgical release of the periosteum
Authors: Simon Timothy M. , Van Sickle David C. , Kunishima Dennis H. , Jackson Douglas W.
Published: May 2003

An autograft of periosteal tissue containing cambium cells has potential to become chondrogenic or osteogenic depending on the regeneration repair strategies. The potential number of harvestable cambium cells diminishes with age. Other factors may be associated with a reduction in the number or variable yields of cambium cells including harvest technique, harvest site location, and the time interval from harvest to implantation. Attempts to increase the number of cambium cells have included improvements in harvesting and handling technique, and expansion of the cells in tissue culture. An „in situ”︁ stimulation and proliferation technique would offer the potential for increasing the number of cambium cells in a cost‐effective manner for transplantation without the need for expansion in tissue culture.

The hypothesis tested was that surgical release of the periosteum and its deep inner underlying cambium layer by sharply incising through the superficial periosteal fibrous layer down to and scoring the cortical bone surface would increase the number of cambium cells that could be harvested at a later time period. Two techniques for periosteal release were used to stimulate a proliferation of the underlying cambium layer and increase the cambium cells for harvest in skeletally mature goats: (1) sharply scoring all four‐sides of the tissue test site perimeter, and (2) sharply scoring only two sides of the tissue test site.

The two‐sided and four‐sided release scoring of the periosteum induced stimulatory responses in the number of cambium cells. In addition, a marked increase in mRNA expression for BMP‐2 (p < 0.001) was observed within 24 h and remained elevated over baseline values for up to 96 h after this stimulation to the cambium layer.

© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Response to Campbell
Authors: AIKHENVALD ALEXANDRA Y.
Published: May 2003

It is the mark of a true scholar to recognise when they have strayed beyond their own area of expertise, and to acknowledge errors.
The Great Tradition Globalizes: Reflections on Two Studies of ‘The
Industrial Leaders’ of Madras
Authors: Harriss John
Published: May 2003

The title of the paper alludes to Milton Singer's book When A Great Tradition Modernizes: an anthropological approach to Indian civilization, and particularly to Part IV of the book. This has the title ‘Modernization and Traditionalization’ and includes a long essay called ‘Industrial Leadership, the Hindu Ethic and the Spirit of Socialism-described in a review by Richard Park at the time as ‘the capstone’ of the book as a whole.
Aboriginal land rights in Russia at the beginning of the twenty-first century
Authors: Fondahl Gail , Poelzer Greg
Published: May 2003

During the last decade, aboriginal peoples in Russia have sought to improve their legal rights, including their rights to their homelands and the resources of these lands. The Russian government initially responded to an aboriginal lobby by including discrete articles addressing aboriginal rights in a number of its laws, including those on forests, sub-surface resources, and protected areas. More comprehensive laws, specifically addressing aboriginal rights to land, were finally adopted at the turn of the twenty-first century, in 1999, 2000, and 2001. This article summarizes the rights of aboriginal peoples regarding land ownership/tenure, access to natural resources (renewable and sub-surface), and protection of ancestral lands, in the light of the new federal legislation. It also notes how the federal laws' provisions concur with international requirements for aboriginal land rights.
The relationship between agoraphobia symptoms and panic disorder in a non-clinical sample of adolescents
Authors: HAYWARD C. , KILLEN J. D. , TAYLOR C. B.
Published: May 2003

Background. The purpose of this study was to evaluate the clinical correlates of agoraphobic fear and avoidance and panic disorder in a non-clinical sample of adolescents.

Method. In a sample of 2365 high school students, combined data from a questionnaire and a structured clinical interview were used to classify subjects with agoraphobic fear and avoidance. Panic symptoms, major depression, childhood separation anxiety disorder, anxiety sensitivity and negative affectivity were also assessed.

Results. Fifteen subjects met study criteria for agoraphobic fear and avoidance in the past year. Only three (20%) of those with agoraphobia symptoms reported histories of panic attacks and there was no overlap between those with agoraphobic fear and avoidance and the 12 subjects who met DSM-III-R criteria for panic disorder. However, subjects with agoraphobia symptoms and those with panic disorder reported similar levels of anxiety sensitivity and negative affectivity. Childhood separation anxiety disorder was more common among those with agoraphobic fear and avoidance compared to those without.

Conclusion. Agoraphobic avoidance is rare in non-clinical samples of adolescents and usually not associated with panic attacks. However, adolescents with agoraphobia symptoms and those with panic disorder have similar clinical correlates consistent with a panic/agoraphobia spectrum model.
Growth hormone responses to low-dose physostigmine administration: functional sex differences (sexual diergism) between major depressives and matched controls
Authors: RUBIN R. T. , ABBASI S. A. , RHODES M. E. , CZAMBEL R. K.
Published: May 2003

Background. Considerable endocrine and non-endocrine evidence supports the hypothesis of increased cholinergic activity relative to noradrenergic activity in major depression. We previously reported functional sex differences (sexual diergism) in hypothalamo–pituitary–adrenal cortical (HPA) hormone responses to the administration of low-dose physostigmine (PHYSO), a cholinesterase inhibitor, in 12 female and eight male unipolar major depressives and 12 female and eight male individually matched control subjects. Because growth hormone (GH) secretion also is influenced by cholinergic mechanisms, we measured GH in the samples from this study.

Method. Subjects underwent four test sessions 5–7 days apart: PHYSO (8 μg/kg i.v.), arginine vasopressin (AVP) (0·08 U/kg i.m.), PHYSO+AVP and saline control. The AVP was administered as a second stimulus to HPA axis hormone secretion. PHYSO and AVP produced no side-effects in about half the subjects and predominantly mild side-effects in the other half, with no significant patient–control differences. Point biserial correlations between side-effects (absent or present) after PHYSO and the corresponding GH responses were non-significant in all groups.

Results. Afternoon baseline GH was significantly higher in the women than in the men, but it was not significantly different between the female or the male patients and their respective matched controls. AVP administration had no effect on GH. PHYSO administration acutely stimulated GH secretion, to a similar degree in the women and men. The depressed patients as a group had a significantly greater average post-PHYSO GH response than did their controls, with a trend toward a significant sex×diagnosis interaction: The female depressives had a significantly greater GH response than their female controls, whereas the male depressives had a similar GH response as their male controls.

Conclusions. These findings suggest sexual diergism (functional sex differences) in baseline and cholinergically stimulated plasma GH measures between major depressives and matched normal controls.
Association between psychotic disorder and urban place of birth is not mediated by obstetric complications or childhood socio-economic position: a cohort study
Authors: HARRISON G. , FOUSKAKIS D. , RASMUSSEN F. , TYNELIUS P. , SIPOS A. , GUNNELL D.
Published: May 2003

Background. Although urban place of birth has been identified as a risk factor for schizophrenia, the extent to which this association is mediated by socially patterned risk factors such as obstetric complications and childhood socio-economic position is unclear. The diagnostic specificity of the association within the clinical psychotic syndromes is also unclear.

Method. A population cohort of 696025 males and females, born in Sweden between 1973 and 1980 and with linked birth and socio-economic data was followed up from age 16 for up to 9·8 years. Hospitalized cases of schizophrenia and other non-affective psychosis were identified from the Swedish Inpatient Discharge Register. We examined associations of these disorders with a three-level measure of urbanicity of birthplace before and after controlling for measures of foetal nutrition, obstetric complications and level of maternal education.

Results. Urban compared to rural birthplace was associated both with increased risk of adult onset schizophrenia (hazard ratio 1·34, CI 0·91–1·96) and other non-affective psychoses (hazard ratio 1·63, CI 1·18–2·26). None of these associations was greatly affected by adjustment for obstetric complications or maternal educational level. In the group of other non-affective psychoses urban–rural differences in disease risk were strongest among those born in the winter months.

Conclusion. Urbanization of birthplace is associated with increased risk of non-affective psychosis but this is not confined to narrowly defined cases. The magnitude of the association in Sweden is lower than that reported in other studies. Causal factors underlying this association appear to operate independently of risks associated with obstetric complications and parental educational status.
Social phobia in the Australian National Survey of Mental Health and Well-Being (NSMHWB)
Authors: LAMPE L. , SLADE T. , ISSAKIDIS C. , ANDREWS G.
Published: May 2003

Background. This article reports data on social phobia from the first large scale Australian epidemiological study. Prevalence rates, demographic correlates and co-morbidity in the sample that met criteria for social phobia are reported and gender differences examined.

Method. Data were obtained from a stratified sample of 10641 participants as part of the Australian National Survey of Mental Health and Well-Being (NSMHWB). A modified version of the Composite International Diagnostic Interview (CIDI) was used to determine the presence of social phobia, as well as other DSM-IV anxiety, affective and substance use disorders. The interview also screened for the presence of nine ICD-10 personality disorders, including anxious personality disorder, the equivalent of DSM-IV avoidant personality disorder (APD).

Results. The estimated 12 month prevalence of social phobia was 2·3%, lower than rates reported in several recent nationally representative epidemiological surveys and closer to those reported in the Epidemiological Catchment Area study (ECA) and other DSM-III studies. Considerable co-morbidity was identified. Data indicated that the co-morbidity with depression and alcohol abuse and dependence were generally subsequent to onset of social phobia and that the additional diagnosis of APD was associated with a greater burden of affective disorder. Social phobia most often preceded major depression, alcohol abuse and generalized anxiety disorder.

Conclusions. Social phobia is a highly prevalent, highly co-morbid disorder in the Australian community. Individuals with social phobia who also screen positively for APD appear to be at greater risk of co-morbidity with all surveyed disorders except alcohol abuse or dependence.