bluuebunny/crossref_metadata_2025 huggingface dataset:
Naphthalene‐1,8‐diyl Bis(Halogenophosphanes): Novel Syntheses and Structures of Useful Synthetic Building Blocks
Authors: Kilian Petr , Slawin Alexandra M. Z. , Woollins J. Derek
Published: December 2002

A series of new bay region disphospha‐functionalised naphthalenes is reported. The reduction of ylidic phosphonium phosphoride NapP2Cl6 (1) (Nap=naphthalene‐1,8‐diyl) with MeOPCl2 gives the important synthon Nap(PCl2)2 (2) in nearly quantitative yield. Reaction of 1 with magnesium metal affords (NapP2)n (3), which reacts with Br2 and I2, yielding Nap(PBr2)2 (4) and Nap(PI)2 (5), respectively. X‐ray structure determinations reveal a twisted geometry of the naphthalene ring in sterically strained 2 and 4, whilst the presence of a PP bond in 5 results in the release of the steric strain and generation of the planar NapP2 moiety. Although the tetrahedral P environments are severely distorted the σ3Pσ3P bonding in 5 represents a new type of PP bonding environment in 1,8‐diphosphanaphthalenes. Compounds 1, 4 and 5 each represent the highest coordination, achievable by direct halogenation. The new compounds 2–5 were fully characterised by NMR, IR, and Raman spectroscopy, mass spectrometry, and elemental analysis.
Total Synthesis of Woodrosin I—Part 1: Preparation of the Building Blocks and Evaluation of the Glycosylation Strategy
Authors: Fürstner Alois , Jeanjean Fabien , Razon Patrick , Wirtz Conny , Mynott Richard
Published: December 2002

The preparation of three building blocks required for the total synthesis of woodrosin I (1) is outlined, a complex resin glycoside bearing a macrolide ring which spans four of the five sugars of its oligosaccharide backbone. Key steps involve the enantioselective, titanium‐catalyzed addition of dipentylzinc to 5‐hexenal, the glycosylation of the resulting alcohol 18 with the glucose‐derived trichloroacetimidate 7, and further elaboration of the resulting product 19 into disaccharide 22 on treatment with the orthogonally protected glycosyl donor 15. The trichloroacetimidate method is also used for the formation of the second synthon represented by disaccharide 38. A model study shows that the assembly of the pentasaccharidic perimeter of 1 depends critically on the phasing of the glycosylation events between fragments 22, 38 and the rhamnosyl donor 27 due to the severe steric hindrance in the product. A particularly noteworthy finding is the fact that diol 22 can be regioselectively glycosylated at the 3′‐OH group in high yield without protection of the neighboring 2′‐OH function.
Total Synthesis of Woodrosin I—Part 2: Final Stages Involving RCM and an Orthoester Rearrangement
Authors: Fürstner Alois , Jeanjean Fabien , Razon Patrick , Wirtz Conny , Mynott Richard
Published: December 2002

The completion of the first total synthesis of the complex resin glycoside woodrosin I (1) is outlined using the building blocks described in the preceding paper. Key steps involve the TMSOTf‐catalyzed coupling of diol 2 with trichloroacetimidate 3 which leads to the selective formation of orthoester 5 rather than to the expected tetrasaccharide. Diene 5, on treatment with catalytic amounts of the Grubbs carbene complex 6 or the phenylindenylidene ruthenium complex 7, undergoes a high yielding ring closing olefin metathesis reaction (RCM) to afford macrolide 8. Exposure of the latter to the rhamnosyl donor 4 in the presence of TMSOTf under “inverse glycosylation” conditions delivers compound 9 by a process involving glycosylation of the sterically hindered 2′‐OH group and concomitant rearrangement of the adjacent orthoester into the desired β‐glycoside. This transformation constitutes one of the most advanced applications of the Kochetkov glycosidation method reported to date. Cleavage of the chloroacetate followed by exhaustive hydrogenation completes the total synthesis of the targeted glycolipid 1.
Gas‐Phase Chemistry of Ethynylamine, ‐Phosphine and ‐Arsine. Structure and Stability of their Cu+and Ni+Complexes
Authors: Galiano Luis , Alcamí Manuel , Mó Otilia , Yáñez Manuel
Published: December 2002

The Cu+and Ni+binding energies of ethynylamine, ethynylphosphine and ethynylarsine have been calculated at the B3LYP/6‐311+G(2df,2p)//B3LYP/6‐311G(d,p) level of theory. Significant differences between nitrogen‐containing and phosphorus‐ or arsenic‐containing compounds have been found regarding structural effects upon metal cation association. While for ethynylamine the global minimum of the potential energy surface corresponds to the complex in which the metal cation binds to theβ‐carbon, for ethynylphosphine the most favourable process corresponds to phosphorus attachment. For ethynylarsine, the conventionalπ‐complex is the most stable one. This behavior resembles that found for the corresponding vinyl analogues, with the only exception being the arsenic derivative. The calculated Cu+and Ni+binding energies for attachment to the heteroatom follow a different trend, P>As>N, to that predicted for the corresponding proton affinities, P>N>As. Cu+and Ni+binding energies are almost identical when the metal cation binds to the heteroatom. However, Ni+binding energies are slightly larger than Cu+binding energies when the metal cation interacts with the CC bond.
Pseudopeptide Foldamers − The Homo‐Oligomers of Benzyl (4S,5R)‐5‐Methyl‐2‐oxo‐1,3‐oxazolidine‐4‐carboxylate
Authors: Tomasini Claudia , Trigari Valerio , Lucarini Simone , Bernardi Fernando , Garavelli Marco , Peggion Cristina , Formaggio Fernando , Toniolo Claudio
Published: December 2002

A 2‐oxo‐1,3‐oxazolidine‐4‐carboxylic acid was designed as a new, conformationally restricted building block for the construction of pseudopeptide foldamers. IR, 1H NMR and CD techniques, implemented by detailed DFT computational modeling, were exploited to investigate the preferred three‐dimensional structure of benzyl (4S,5R)‐5‐methyl‐2‐oxo‐1,3‐oxazolidine‐4‐carboxylate homo‐oligomers synthesized to the pentamer level. The resulting poly(L‐Pro)n II like helical conformation was found to be stabilized by intramolecular α‐C−H···O=C hydrogen bonds. This novel, acylurethane‐based, ternary foldameric structure, if appropriately functionalized, holds promise as a robust template for a variety of applications. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Asymmetric Synthesis of (S)‐4‐Oxopipecolic Acid by a 3+3 Atom‐Unit Assembly Strategy
Authors: Partogyan‐Halim Karolin , Besson Laure , Aitken David J. , Husson Henri‐Philippe
Published: December 2002

(S)‐4‐Oxopipecolic acid has been prepared in enantiomerically pure form from two readily accessible starting materials, (R)‐N‐(cyanomethyl)‐4‐phenyloxazolidine (2) and 2‐(methoxymethoxy)allyl chloride, (3, MOM‐allyl chloride). This strategy exploits the complementary electrophile/nucleophile reactivity at each end of this pair of 3‐atom unit building blocks. Thus, alkylation of the anion of 2 with 3 (creation of the piperidine C‐2−C‐3 bond) followed by Lewis acid induced cyclisation (creation of the C‐5−C‐6 bond), leads principally to a bicyclic intermediate 5 which incorporates a protected form of the title compound. Subsequent chemical transformations lead to the target molecule in an overall yield of 20% for the five‐step sequence. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
A Novel Approach to 2‐Chloro‐2‐fluorostyrenes
Authors: Nenajdenko Valentine G. , Shastin Alexey V. , Korotchenko Vasily N. , Varseev Georgy N. , Balenkova Elisabeth S.
Published: December 2002

A new general catalytic olefination reaction (COR) of aromatic and heteroaromatic aldehydes and ketones was applied to synthesise 2‐chloro‐2‐fluorostyrenes. The two‐stage procedure includes the transformation of carbonyl compounds into hydrazones followed by treatment with CFCl3 mediated by copper catalysis. Trichlorofluoromethane was used as a chlorofluoromethylene transfer reagent. The reaction proceeds stereoselectively and the target alkenes were obtained in high yield. A proposed mechanism for the reaction is discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Brominated Oxylipins and Oxylipin Glycosides from Red Sea Corals
Authors: Řezanka Tomáš , Dembitsky Valery M.
Published: December 2002

Eight new brominated oxylipins 1−8, including two glycosides, were isolated from the Red Sea invertebrates Dendrophyllia sp., Dendronephthya sp. (red variety), Dendronephthya sp. (yellow variety), and Tubipora musica. Their structures were elucidated mainly on the basis of NMR spectroscopic data. The relative and absolute configurations were determined by analysis of NOESY and CD data and by the modified Mosher method. The compounds gave positive results in a brine shrimp toxicity assay, a sea urchin eggs test (Paracentrotus lividus), and a crown gall tumor on potato disks test (Agrobacterium tumefaciens). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Isolation and Structural Determination of Four New Ceramide Lactosides from the Starfish Luidia maculata
Authors: Inagaki Masanori , Nakamura Kazufumi , Kawatake Satoshi , Higuchi Ryuichi
Published: December 2002

Four new ceramide lactosides, luidialactoside A (1), B (3), C (4), and D (5) were isolated from the water‐insoluble lipid fraction of the CHCl3/MeOH extract of the starfish Luidia maculata. The structures of these ceramide lactosides were determined on the basis of chemical and spectroscopic evidence. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Injection Moulding: Evaluation of Appropriate Melt Injection Points for the Gas Injection Technique
Authors: Heim Hans‐Peter
Published: December 2002

In gas assisted injection moulding the melt front advancement has a considerable effect on the gas penetration. The evaluation of an appropriate melt filling is an important step to avoid instabilities in the process sequence. Taking a sample moulded part a procedure is presented that enables the part designer to evaluate required melt and gas injection points according to the gas injection technique. Using finite element simulations, different calculations for the melt front advancement lead to the correct gate location.

Presentation of different degrees of filling for the optimised article geometry.

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Presentation of different degrees of filling for the optimised article geometry.
Development of a Portable Online Rheometer for the Characterization of PVC Melts
Authors: Limper Andreas , Fattmann Gordon , Seibel Stefan
Published: December 2002

Poly(vinyl chloride) (PVC) is a standard polymer with a world‐wide sales quantity of more than 20 Mio. t. From a rheological point of view, PVC is much more difficult to classify than for example polyethylene. Standard thermoplastics can be plasticized by the input of thermal energy, whereas for a sufficient plastification of PVC shear energy is needed. Hence, the PVC melt properties measured with the help of standard lab‐scale rheometers are not taking the shear history into account. Therefore, the melt behavior within an extruder cannot be described. In addition, PVC melts show wall slipping effects. A new rheometer concept especially developed to characterize PVC melt is presented. The rheometer takes a representative melt stream between the screw tip and the inflow of the die. The pressure gradient of this melt stream is measured within the geometry of the rheometer. Due to this the shear history and the wall slipping effects can be accounted for. Experimental data and results are presented and the application possibilities such as the design of profile dies and the development of PVC recipes are discussed.

The portable online rheometer in the assembled state.

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The portable online rheometer in the assembled state.
Scale‐Up in the Design of Extrusion Dies
Authors: Potente Helmut , Kramme Sandra
Published: December 2002

The similarity theory and the scale‐up procedure developed from it make it possible to convert a technical‐physical process from one scale to another – generally in the upwards direction. In the design of extrusion dies with an annular die gap, the die is broken down into basic geometric elements, and scale‐up rules are then drawn up for the individual elements. In this project, scale‐up rules were found that satisfy both full and partial similarity. The pseudoplasticity and elasticity of the melt were also taken into consideration. A comparison of the model laws obtained with the results of finite element calculations showed good conformity between the models and the production versions.

Deviation in pressure difference between the model and the production version assuming flow behavior in accordance with the power law (Di = const. and L = const.).

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Deviation in pressure difference between the model and the production version assuming flow behavior in accordance with the power law (Di = const. and L = const.).
Analysis of the Influence of Rotor Design on the Stream Flow Conditions Within an Internal Mixer
Authors: Limper Andreas , Wilhelmsmeyer Tom
Published: December 2002

A flow visualisation apparatus is described which allows to compare different rotor designs to each other. In order to observe the distributive mixing effect, the stream flow and dispersive mixing effect is monitored by an indirect measurement of the power impact within the material. Assuming that the mixing process of an internal mixer is not continuous, a testing device was build to the scale of a 90 l kneader. In this device the mixing chamber and the rotor blade are unwound into the flat plane. With this testing device it is possible to carry out a systematic analysis of the influence of rotor design on the flow processes within an internal mixer in a fast and inexpensive way.

The test device.

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The test device.
Compounding Unit Planetary Roller Extruder
Authors: Limper Andreas , Seibel Stefan , Fattmann Gordon
Published: December 2002

Planetary roller extruders (PREs) are currently being employed first and foremost to feed calender/lamination units, for pelleting, for compounding powdered paint and for the reuse of recyclate. In these disciplines it is the most successful multi‐screw extruder. The range of materials that are compounded extends from classical plasticised poly(vinyl chloride) (PVC), via poly(propylene) (PP) and acrylonitrile‐butadiene‐styrene (ABS), through to powdered rubber. The planetary roller extruders convince in comparison with other compounding machines through the thermally carefully compounding, the balanced ratio of shear and heat transfer and the narrow residence time distribution. Experimental investigations to analyze the process behavior of PREs were carried out for the first time.

Homogenization and dispersion at a material‐bank in the planetary roller extrusion test stand.

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Homogenization and dispersion at a material‐bank in the planetary roller extrusion test stand.
Genetic mutation associated with meiotic metaphase‐specific apoptosis in MRL/MpJ mice
Authors: Namiki Yuka , Endoh Daiji , Kon Yasuhiro
Published: December 2002

It has been reported that the MRL/MpJ mouse strain shows several unique phenotypes, including rapid wound healing, inherent collagen disease, heat shock‐resistant spermatocytes, and metaphase‐specific apoptosis (Msa) in the testis. In the present study, we found the genetic mutation associated with Msa by chromosomal mapping with 555 backcross progeny. The Sertoli cell index of abnormal metaphasic spermatocytes was clearly divided into two groups in the first 200 male backcross progeny, which were created by mating female F1 (female C57BL/6 × male MRL/MpJ) with male MRL/MpJ mice, indicating that Msa was caused by only one gene. The result of chromosomal mapping throughout the 555 backcross progeny by using microsatellite markers and single nucleotide polymorphism (SNP) revealed that Msa was mapped on the telomeric region of chromosome 1 and was significantly linked with exonuclease 1 (Exo1) and choroideremia‐like (rab escort protein 2) (Chml/Rep2) genes. It was found that the Chml/Rep2 gene was not a candidate for Msa by means of the nucleotide sequences of several inbred strains. On the Exo1 gene in strain MRL/MpJ, but not in other strains, it was surprisingly noted that the truncated forms (tr1‐Exo1 and tr2‐Exo1) were expressed in all tissues examined as well as normal Exo1 by reverse transcriptase‐polymerase chain reaction (RT‐PCR). Additionally, the truncated forms of the Exo1 gene were suggested to be transcribed by alternative splicing of the 9th exon, possibly resulting from nucleotide substitution of the branch site existing in the 8th intron. These results suggested that the testicular meiotic Msa in MRL/MpJ mice was a unique phenotype caused by incomplete alternative splicing of the Exo1 gene. Mol. Reprod. Dev. 64: 179–188, 2003. © 2003 Wiley‐Liss, Inc.
Expression in Escherichia coli and immunological characterization of three zona pellucida proteins (ZP1, ZP2, and ZP3) from a marsupial, the brushtail possum (Trichosurus vulpecula)
Authors: Mate Karen E. , Buist Janine M. , Duckworth Janine A.
Published: December 2002

The brushtail possum (Trichosurus vulpecula) zona pellucida (ZP) is composed of three major glycoproteins, designated ZP1, ZP2, and ZP3 based on their size and homology with eutherian ZP proteins. These proteins are candidate antigens for the development of an immunocontraceptive vaccine to control the fertility of the brushtail possum in New Zealand, where it is an introduced pest. In order to further their immunological and functional characterization, recombinant possum ZP proteins were produced in Escherichia coli (E. coli) strain JM109, M15, SG13009, or BL21 codon plus. Each of the proteins produced possessed a N‐terminal six histidine tag (His)6 to facilitate purification and consisted of amino acid (aa) residues 18–471 of possum ZP1, aa residues 40–311 of ZP2 (ZP2‐N), aa residues 305–634 of ZP2 (ZP2‐C), and aa residues 23–342 of ZP3. Immunoblot using anti‐RGS(His)4 antibodies and polyclonal rabbit anti‐porcine ZP antibodies detected major bands at 54 kDa for ZP1, 32 kDa for ZP2‐N, 39 kDa for ZP2‐C, and 40 kDa for ZP3. Immunization of male and female rabbits with ZP2‐N, ZP2‐C, and ZP3 purified on Ni‐NTA resin under denaturing conditions generated antibodies reactive with recombinant ZP proteins on Western blot and with native ZP proteins in possum ovarian sections using immunofluorescence. Antibodies generated against ZP1 in the same way were reactive with recombinant ZP proteins on Western blot only. The recombinant possum ZP proteins and specific antibodies produced in this study give an indication of the antigenic relationship of the possum ZP proteins and are vital tools for future studies of sperm‐ZP binding in marsupials and for the evaluation of ZP‐based contraceptive vaccines in possums and other marsupials. Mol. Reprod. Dev. 64: 136–143, 2003. © 2003 Wiley‐Liss, Inc.
Isolation and partial characterization of three pregnancy‐associated glycoproteins from the ewe placenta
Authors: El Amiri Bouchra , Remy Benoit , Sousa Noelita Melo , Joris Bernard , Ottiers Nicole Gerardin , Perenyi Zsolt , Mboko Henri Banga , Beckers Jean‐Francois
Published: December 2002

Pregnancy‐associated glycoproteins (PAGs) are synthesized in the outer epithelial layer of the placenta in artiodactyls. In this work, three novel ovine PAGs were isolated from late‐pregnancy fetal cotyledons and characterized biochemically. The isolation procedure included acid and ammonium sulfate precipitations and anion and cation exchange chromatographies. The isolated PAGs have different NH2‐terminal amino acid sequences (RGSXLTILPLRNMRDIVY, ISRVSXLTIHPLRNIMDML, and RGSNLTIHPLRNIRD) and apparent molecular masses (55, 57, and 59 kDa). Each shows several isoforms with different pI values. The three proteins share high sequence identity with each other and with other ovine, bovine, and caprine PAGs. They have not been described previously. The ovPAG‐59 sequence differs from the previously identified ovPAG‐4 sequence (determined by DNA cloning and sequencing) at only one position among the 15 N‐terminal residues. The newly characterized ovPAGs and the procedure used to isolate them will be helpful in producing new antisera for investigating PAG secretion in pregnant ewes. Mol. Reprod. Dev. 64: 199–206, 2003. © 2003 Wiley‐Liss, Inc.
Classical cadherin and catenin expression in normal myometrial tissues and uterine leiomyomas
Authors: Tai Chin‐Tao , Lin Wu‐Chou , Chang Wei‐Chun , Chiu Tsan‐Hung , Chen George T.C.
Published: December 2002

Uterine leiomyomas are the most common benign uterine tumors in the women of reproductive age. Previous studies have suggested that uterine leiomyomas are monoclonal tumors derived from a single neoplastic myometrial cell. However, the neoplastic transformation of myometrium to leiomyomas remains to be elucidated. The classical cadherins are a gene family of integral membrane glycoproteins that mediate calcium‐dependent cell–cell adhesion in a homophilic manner. These cell adhesion molecules (CAMs) have been shown to play pivotal roles in tumorigenesis. Catenins are intracellular proteins that link the cytoplasmic domains of the cadherins to the cytoskeletons to promote the biological functions of these CAMs. In this study, we compared the expression of E‐, N‐, and P‐cadherins and α‐, β‐, and γ‐catenins in the uterine leiomyomas and the counterparts of normal myometrium of the same patients by using semiquantitative reverse transcription‐polymerase chain reaction (RT‐PCR) and Western blot analysis. Of these, E‐cadherin (E‐cad) was not detected in both uterine leiomyomas and myometrium, P‐cadherin (P‐cad) was similarly expressed in these two tissues, but N‐cadherin (N‐cad) mRNA and protein expression levels in uterine leiomyomas were significantly greater than those observed in the myometrium. Catenins were not differentially expressed in uterine myometrium and leiomyomas. The overexpression of N‐cad in uterine leiomyomas suggests that this CAM may play a central role in the development of uterine leiomyomas. Mol. Reprod. Dev. 64: 172–178, 2003. © 2003 Wiley‐Liss, Inc.
Raman spectroscopy of heavily doped polycrystalline and microcrystalline silicon
Authors: Lengsfeld P. , Brehme S. , Brendel K. , Genzel Ch. , Nickel N. H.
Published: December 2002

Raman measurements of heavily doped laser crystallized poly‐Si and as‐deposited μc‐SH show significant differences between the two materials. Poly‐Si samples exhibit the Fano effect just like heavily doped c‐Si samples. This is not true for the heavily doped μc‐SH samples.
Complexes of point defects and impurities in electron‐irradiated n‐type Cz‐Si pre‐doped with hydrogen
Authors: Nakanishi A. , Fukata N. , Suezawa M.
Published: December 2002

Complexes of point defects and impurities in electron‐irradiated n‐type Czochralski‐grown Si (CSi) pre‐doped with hydrogen (H) were studied and the results compared with those in high‐purity specimens. Specimens were n‐type (1.3 Ω cm) Cz‐Si. They were irradiated with 3 MeV electrons at room temperature after hydrogen doping. Optical absorption spectra were measured at 7 K. Spectra were recorded in three wavenumber ranges: 800–1000, 1800–2200 and around 2700 cm–1. In the first range, optical absorption peaks were observed due to H*2, VO0 (neutral charge state) and VO– (negatively charged state). The concentration of the VO pair in n‐type specimens was higher than that in high‐purity specimens. In the second range, peaks were observed due to H*2 and complexes of self‐interstitials and H2. In the third range, peaks were observed due to V2. Due to the isochronal annealing, VO0 decreased in two stages, 75–200 and 200–400 °C. In the first stage, two new peaks appeared, at 2126 and 2151 cm–1. They disappeared in the second stage. The activation energies of the first and second stages were about 0.8 and 1.6 eV, respectively.
Photoluminescence studies of isotopically enriched silicon
Authors: Karaiskaj D. , Thewalt M.L. W. , Ruf T. , Cardona M.
Published: December 2002

We report the first high resolution photoluminescence studies of isotopically pure silicon. New information is obtained on isotopic effects on the indirect band gap energy, phonon energies, and phonon broadenings, which is in good agreement with previous results obtained in germanium and diamond. Remarkably, the line widths of the no‐phonon boron and phosphorus bound exciton transitions in the 28Si sample (99.896% 28Si) are much sharper than in natural Si, revealing new fine structure in the boron bound exciton luminescence. Most surprisingly, the small splittings of the neutral acceptor ground state in natural Si are absent in the photoluminescence spectra of acceptor bound excitons in isotopically purified 28Si, demonstrating conclusively that they result from the randomness of the Si isotopic composition.
Screening for cyanobacterial hepatotoxins in herring and salmon from the Baltic Sea
Authors: Sipiä Vesa O. , Lahti Kirsti , Kankaanpää Harri T. , Vuorinen Pekka J. , Meriluoto Jussi A. O.
Published: December 2002

Nodularin, a cyclic pentapeptide hepatotoxin closely related to microcystins, is produced by the toxic brackish water cyanobacterium Nodularia spumigena which regularly forms blooms in the Baltic Sea. Baltic herring (Clupea harengus membras L.) and salmon (Salmo salar L.) were caught in the Baltic Sea during 1997 to assess levels of nodularin and microcystins resulting from the blooms. The total toxin content in herring muscle and salmon liver was measured with an enzyme-linked immunosorbent assay. Despite exceptionally heavy blooms of toxic Nodularia in the Baltic Sea during the summer of 1997, Baltic herring and salmon contained very low quantities of nodularin and microcystins (2.5–6.5 ng g–1 dry weight, not corrected for recovery, [30%]). These concentrations do not pose a health threat to humans, based on the World Health Organization value of tolerable daily intake. Moreover, the concentrations we found in salmon and herring were much lower than those reported for livers of European flounder (Platichthys flesus L.) or Atlantic cod (Gadus morhua L.) from the Baltic Sea during 1996–1999. We suspect that cyanobacterial hepatotoxins do not effectively accumulate in herring and salmon.
A Brown Tide Bloom Index based on the potential harmful effects of the brown tide alga, Aureococcus anophagefferens
Authors: Gastrich Mary Downes , Wazniak Catherine E.
Published: December 2002

Harmful algal blooms are an increasing phenomenon in coastal areas of the world. Recurring harmful brown tides caused by the minute alga, Aureococcus anophagefferens, are a regional problem in the northeast Atlantic states of the United States. Brown tide blooms may cause significant ecological impacts on natural resources. A Brown Tide Bloom Index was developed based on published scientific studies and agency reports that relates concentrations of the brown tide organism to potential negative impacts on natural resources including shellfish, seagrasses and protozoa. For the first time, the index provides terminology that can be used to convey accurate information about impacts to natural resources resulting from concentrations of brown tide to scientists, environmental managers and the public. The purpose of the Brown Tide Bloom Index is to provide a metric, based on available scientific studies, which can be used by environmental managers to communicate the magnitude of brown tide blooms and impacts to natural resources. The Brown Tide Bloom Index includes three categories of brown tide blooms: Category 1 blooms (algal concentrations at <35,000 cells ml−1) have no reported impacts; Category 2 blooms (≥35,000 to <200,000 cells ml−1) have potential negative impacts on feeding and growth in shellfish; Category 3 blooms (≥200,000 cells ml−1), discolor the water a yellow-brown and may cause severe impacts and mortality on shellfish, reduction in seagrasses and planktonic organisms.
Heavy metals in biota from Sundarban Wetland Ecosystem, India: Implications to monitoring and environmental assessment
Authors: Sarkar S. K. , Bhattacharya B. , Debnath S. , Bandopadhaya G. , Giri Sankar
Published: December 2002

The coastal environment of West Bengal is recognized as the most diversified and productive ecosystem among all the maritime states of India. This area faces organic pollution from domestic sewage and toxic pollution from industrial effluents leading to serious impacts on water and sediment quality as well as on biodiversity. This article aims at providing information on concentration levels of heavy metals (iron, zinc, copper, manganese, cadmium, and mercury) in the tissues of a suspension feeder bivalve Macoma birmanica, whole body tissues of five gastropods (Cerithidea cingulata, C. obtusa, Telescopium telescopium, Thais lacera and Nerita articulata) and four finfishes (Liza tade, Harpodon nehereus, Trichiurus sp., and Boleopthalmus sp.) collected from water bodies of Sagar Island (22° 19′ N; 80° 03′ E), the largest delta of Sundarbans.

A general trend with the following in decreasing order occurred: Fe>Zn>Mn>Cu>Cd>Hg. Both species-dependent variability and temporal variations were pronounced. A high degree of organ specificity was evident in M. birmanica where gill and mantle exhibited higher metal accumulation due to the ion exchange property of the mucous layer covering these organs. Gastropods and finfishes were differentially selective for a range of metals, reflecting the availability of the elements in the environment and the diet and digestive physiology of these organisms. An overall elevated concentration of these metals was observed during monsoon months when low pH and salinity prevailed in the ambient medium. A continuous monitoring program is recommended to establish the studied organisms as bioindicators and to identify future changes to conserve the “health” of this fragile ecosystem.
On the Mechanism of MgATP-dependent Gating of CFTR Cl− Channels
Authors: Vergani Paola , Nairn Angus C. , Gadsby David C.
Published: December 2002

CFTR, the product of the gene mutated in cystic fibrosis, is an ATPase that functions as a Cl− channel in which bursts of openings separate relatively long interburst closed times (τib). Channel gating is controlled by phosphorylation and MgATP, but the underlying molecular mechanisms remain controversial. To investigate them, we expressed CFTR channels in Xenopus oocytes and examined, in excised patches, how gating kinetics of phosphorylated channels were affected by changes in [MgATP], by alterations in the chemical structure of the activating nucleotide, and by mutations expected to impair nucleotide hydrolysis and/or diminish nucleotide binding affinity. The rate of opening to a burst (1/τib) was a saturable function of [MgATP], but apparent affinity was reduced by mutations in either of CFTR's nucleotide binding domains (NBDs): K464A in NBD1, and K1250A or D1370N in NBD2. Burst duration of neither wild-type nor mutant channels was much influenced by [MgATP]. Poorly hydrolyzable nucleotide analogs, MgAMPPNP, MgAMPPCP, and MgATPγS, could open CFTR channels, but only to a maximal rate of opening ∼20-fold lower than attained by MgATP acting on the same channels. NBD2 catalytic site mutations K1250A, D1370N, and E1371S were found to prolong open bursts. Corresponding NBD1 mutations did not affect timing of burst termination in normal, hydrolytic conditions. However, when hydrolysis at NBD2 was impaired, the NBD1 mutation K464A shortened the prolonged open bursts. In light of recent biochemical and structural data, the results suggest that: nucleotide binding to both NBDs precedes channel opening; at saturating nucleotide concentrations the rate of opening to a burst is influenced by the structure of the phosphate chain of the activating nucleotide; normal, rapid exit from bursts occurs after hydrolysis of the nucleotide at NBD2, without requiring a further nucleotide binding step; if hydrolysis at NBD2 is prevented, exit from bursts occurs through a slower pathway, the rate of which is modulated by the structure of the NBD1 catalytic site and its bound nucleotide. Based on these and other results, we propose a mechanism linking hydrolytic and gating cycles via ATP-driven dimerization of CFTR's NBDs.
Immunotherapy with a posttranscriptionally modified DNA vaccine induces complete protection against metastatic neuroblastoma
Authors: Pertl Ursula , Wodrich Harald , Ruehlmann J. Michael , Gillies Stephen D. , Lode Holger N. , Reisfeld Ralph A.
Published: December 2002

The successful induction of a T-cell–mediated tumor-protective immunity against poorly immunogenic malignancies remains a major challenge for cancer immunotherapy. We achieved this by immunization with a tyrosine hydroxylase (mTH)–based DNA vaccine, enhanced with the posttranscriptional regulatory acting RNA element (WPRE), derived from woodchuck hepatitis virus in combination with an antibody-cytokine fusion protein (ch14.18–IL-2) that targets interleukin-2 (IL-2) to the tumor microenvironment. This DNA vaccine mTH-WPRE was carried by attenuated Salmonella typhimurium and applied by oral gavage in a mouse model of neuroblastoma. Mice immunized with the mTH-WPRE vaccine, and which additionally received a boost with suboptimal doses of ch14.18–IL-2, were completely protected against hepatic neuroblastoma metastases. In contrast, all controls presented with disseminated metastases. Both T-cell and natural killer (NK) cell–dependent mechanisms were involved in the induction of a systemic tumor-protective immunity. Thus, up-regulation of interferon-γ (IFN-γ) expression in CD8+ T cells occurred only in those animals that received the mTH-WPRE vaccine plus the ch14.18–IL-2 boost. Up-regulation of this proinflammatory cytokine was not observed in mice immunized with mTH-WPRE vaccine alone. A role for NK cells was indicated by the complete abrogation of systemic tumor-protective immunity in all animals that were depleted of NK cells in vivo. Taken together, these data demonstrate that immunization with a posttranscriptionally enhanced DNA vaccine encoding the WPRE sequence, combined with a boost of the ch14.18–IL-2 fusion protein, completely protects against hepatic metastases in a murine model of neuroblastoma and therefore may lead to a new strategy for immunotherapy and prevention of metastatic neuroblastoma.
Glycosphingolipid expression in acute nonlymphocytic leukemia: common expression of shiga toxin and parvovirus B19 receptors on early myeloblasts
Authors: Cooling Laura L. W. , Zhang De Sheng , Naides Stanley J. , Koerner Theodore A. W.
Published: December 2002

Glycosphingolipids (GSLs) are complex macromolecules on cell membranes that have been shown to play a role in neutrophil differentiation, activation, phagocytosis, and adhesion to both microorganisms and vascular endothelium. Because GSLs are often cryptic antigens on cell membranes, little is known regarding GSL expression in early myelopoiesis. To study the latter, myeloblasts were collected from patients with acute nonlymphocytic leukemia (ANLL) who required therapeutic leukocytopheresis for hyperleukocytosis. The neutral GSLs were isolated and identified by high-performance thin-layer chromatography (HPTLC), HPTLC immunostaining, gas chromatography, nuclear magnetic resonance, and fast atom bombardment–mass spectrometry. Like mature peripheral blood neutrophils, myeloblasts expressed glucosylceramide, lactosylceramide, and the neolacto-family GSLs, lactotriaosylceramide and neolactotetraosylceramide. Unlike neutrophils and chronic myeloid leukemia, most ANLL samples also expressed the globo-series GSLs, globotriaosylceramide and globotetraosylceramide. Globo GSL expression was strongly associated with a myeloblastic (ANLL M0-M2) and monoblastic phenotype (M5). A weak association was also noted with expression of either lymphoid (P < .10) or early hematopoietic markers (terminal deoxynucleotidyl transferase [TdT], CD34; P < .10). Globo-positive ANLL samples bound both shiga toxin and parvovirus B19 on HPTLC immunostaining. Based on these findings, we propose that neolacto and globo GSLs are expressed during early myeloid differentiation. Globotriaosylceramide expression on myeloblasts, and possibly myeloid stem cells, may have important implications for the use of shiga toxin as an ex vivo purging agent in autologous stem cell transplantation. Expression of globotetraosylceramide, the parvovirus B19 receptor, on myeloblasts may also explain the association between B19 infection, aplastic anemia, and chronic neutropenia of childhood.
Malaria-parasitized erythrocytes and hemozoin nonenzymatically generate large amounts of hydroxy fatty acids that inhibit monocyte functions
Authors: Schwarzer Evelin , Kühn Hartmut , Valente Elena , Arese Paolo
Published: December 2002

Plasmodium falciparum digests up to 75% of erythrocyte (red blood cell [RBC]) hemoglobin and forms hemozoin. Phagocytosed hemozoin and trophozoites inhibit important monocyte functions. Delipidized trophozoites and hemozoin were remarkably less toxic to monocytes. Parasitized RBCs and hemozoin contained large amounts of mostly esterified monohydroxy derivatives (OH-PUFAs), the stable end products of peroxidation of polyenoic fatty acids. The concentrations of OH-PUFA were 1.8 micromoles per liter RBCs in nonparasitized RBCs, 11.1 micromoles per liter RBCs in rings, 35 micromoles per liter RBCs in trophozoites; and approximately 90 micromoles per liter RBC equivalents in hemozoin. In parasitized RBCs and hemozoin a complex mixture of monohydroxy derivatives of arachidonic (HETEs) and linoleic (HODEs) acid was determined. Respectively, 13- and 9-HODE and 9- and 12-HETE were predominant in hemozoin and parasitized RBCs. The estimated concentrations of all HETE isomers were 33 and 39 micromoles per liter RBCs or RBC equivalents in trophozoites and hemozoin, respectively. No evidence of lipoxygenase activity was found, whereas the large number of positional and optical isomers, the racemic structure, and their generation by incubation of arachidonic acid with hemozoin indicated nonenzymatic origin via heme-catalysis. Sub/low micromolar concentrations of 12- and 15-HETE were toxic to monocytes, whereas HODE isomers were ineffective. Low micromolar concentrations of HETE isomers were estimated to be similarly present in monocytes after phagocytosis of trophozoites or hemozoin. Thus, specific products of heme-catalyzed lipid peroxidation appear to contribute to hemozoin toxicity to phagocytes and may thus play a role in increased cytoadherence, vascular permeability, and chemotaxis, as well as in immunodepression in malaria.
Tissue distribution of target antigen has a decisive influence on the outcome of adoptive cancer immunotherapy
Authors: Meunier Marie-Christine , Roy-Proulx Guillaume , Labrecque Nathalie , Perreault Claude
Published: December 2002

Adoptive transfer of allogeneic T cells has unmatched efficacy to eradicate leukemic cells. We therefore sought to evaluate in kinetic terms interactions between T cells and allogeneic leukemic cells. T cells primed against the model B6dom1 minor histocompatibility antigen were adoptively transferred in irradiated B10 (B6dom1-positive) and congenic B10.H7b (B6dom1-negative) recipients, some of which were also injected with EL4 leukemia/lymphoma cells (B6dom1-positive). A key finding was that the tissue distribution of the target epitope dramatically influenced the outcome of adoptive cancer immunotherapy. Widespread expression of B6dom1 in B10 recipients induced apoptosis and dysfunction of antigen-specific T cells. Furthermore, in leukemic B10 and B10.H7b hosts, a massive accumulation of effector/memory B6dom1-specific T cells was detected in the bone marrow, the main site of EL4 cell growth. The accumulation of effector/memory cells in recipient bone marrow was EL4 dependent, and its kinetics was different from that observed in recipient spleen. We conclude that strategies must be devised to prevent apoptosis of adoptively transferred T cells confronted with a high antigen load and that local monitoring of the immune response at the site of tumor growth may be mandatory for a meaningful assessment of the efficacy of adoptive immunotherapy.
Megakaryocyte polyploidization is associated with a functional gene amplification
Authors: Raslova Hana , Roy Lydia , Vourc'h Claire , Le Couedic Jean Pierre , Brison Olivier , Metivier Didier , Feunteun Jean , Kroemer Guido , Debili Najet , Vainchenker William
Published: December 2002

It is believed that polyploidy induces an orchestrated increase in gene expression. To know whether all alleles remain functional during megakaryocyte polyploidization, we used a well-established fluorescence in situ hybridization technique which allows one to simultaneously detect pre-mRNAs and assess ploidy level in a single cell. All alleles of GPIIb, GPIIIa,VWF, β-actin, hsp70,c-mpl, Fli-1, and FOG-1 genes are transcriptionally active in megakaryocytes from 4N to 32N. All X chromosomes in male cells are transcriptionally active but only half of them are transcriptionally active in female megakaryocytes, as revealed by the transcriptional activity of the GATA-1gene. Nuclear untranslated XIST RNA accumulates on the inactivated X chromosomes, indicating that they are subjected to a normal inactivation process. Altogether, our results demonstrate that megakaryocyte polyploidization results in a functional gene amplification whose likely function is an increase in protein synthesis parallel with cell enlargement.
Revealing lymphoma growth and the efficacy of immune cell therapies using in vivo bioluminescence imaging
Authors: Edinger Matthias , Cao Yu-An , Verneris Michael R. , Bachmann Michael H. , Contag Christopher H. , Negrin Robert S.
Published: December 2002

Cancer therapeutics have achieved success in the treatment of a variety of malignancies, however, relapse of disease from small numbers of persistent tumor cells remains a major obstacle. Advancement of treatment regimens that effectively control minimal residual disease and prevent relapse would be greatly accelerated if sensitive and noninvasive assays were used to quantitatively assess tumor burden in animal models of minimal residual disease that are predictive of the human response. In vivo bioluminescence imaging (BLI) is an assay for the detection of small numbers of cells noninvasively and enables the quantification of tumor growth within internal organs. Fusion genes that encode bioluminescent and fluorescent reporter proteins effectively couple the powerful in vivo capabilities of BLI with the subset-discriminating capabilities of fluorescence-activated cell sorting. We labeled 2 murine lymphoma cell lines with dual function reporter genes and monitored radiation and chemotherapy as well as immune-based strategies that employ the tumorcidal activity of ex vivo–expanded CD8+ natural killer (NK)–T cells. Using BLI we were able to visualize the entire course of malignant disease including engraftment, expansion, metastasis, response to therapy, and unique patterns of relapse. We also labeled the effector NK-T cells and monitored their homing to the sites of tumor growth followed by tumor eradication. These studies reveal the efficacy of immune cell therapies and the tempo of NK-T cell trafficking in vivo. The complex cellular processes in bone marrow transplantation and antitumor immunotherapy, previously inaccessible to investigation, can now be revealed in real time in living animals.
Transcriptional accessibility for genes of multiple tissues and hematopoietic lineages is hierarchically controlled during early hematopoiesis
Authors: Akashi Koichi , He Xi , Chen Jie , Iwasaki Hiromi , Niu Chao , Steenhard Brooke , Zhang Jiwang , Haug Jeff , Li Linheng
Published: December 2002

Hematopoietic stem cells (HSCs) maintain hematopoiesis by giving rise to all types of blood cells. Recent reports suggest that HSCs also possess the potential to generate nonhematopoietic tissues. To evaluate the underlying mechanisms in the commitment of HSCs into multitissue and multihematopoietic lineages, we performed oligonucleotide array analyses targeting for prospectively purified HSCs, multipotent progenitors (MPPs), common lymphoid progenitors (CLPs), and common myeloid progenitors (CMPs). Here we show that HSCs coexpress multiple nonhematopoietic genes as well as hematopoietic genes; MPPs coexpress myeloid and lymphoid genes; CMPs coexpress myeloerythroid, but not lymphoid genes, whereas CLPs coexpress T-, B-, and natural killer–lymphoid, but not myeloid, genes. Thus, the stepwise decrease in transcriptional accessibility for multilineage-affiliated genes may represent progressive restriction of developmental potentials in early hematopoiesis. These data support the hypothesis that stem cells possess a wide-open chromatin structure to maintain their multipotentiality, which is progressively quenched as they go down a particular pathway of differentiation.
Radioimmunotherapy of non-Hodgkin lymphomas
Authors: Cheson Bruce D.
Published: December 2002

Enthusiasm for the use of monoclonal antibodies, such as rituximab, has markedly changed the approach to patients with non-Hodgkin lymphomas (NHLs). Nevertheless, more effective therapies are needed. Radioimmunotherapy as a form of targeted radiation therapy may add significantly to our therapeutic options. Yttrium Y 90 ibritumomab tiuxetan, recently approved by the Food and Drug Administration, and iodine I 131 tositumomab have demonstrated a high level of activity in patients whose NHL has failed to respond to chemotherapy and rituximab. Toxicities have primarily included prolonged myelosuppression, with a potential risk of treatment-associated myelodysplastic syndrome and acute myelogenous leukemia. Ongoing clinical trials are attempting to better characterize the role of these promising agents.
Phase 1 and pharmacodynamic studies of G3139, a Bcl-2 antisense oligonucleotide, in combination with chemotherapy in refractory or relapsed acute leukemia
Authors: Marcucci Guido , Byrd John C. , Dai Guowei , Klisovic Marko I. , Kourlas Peter J. , Young Donn C. , Cataland Spero R. , Fisher Diane B. , Lucas David , Chan Kenneth K. , Porcu Pierluigi , Lin Zhong-Pin , Farag Sherif F. , Frankel Stanley R. , Zwiebel James A. , Kraut Eric H. , Balcerzak Stanley P. , Bloomfield Clara D. , Grever Michael R. , Caligiuri Michael A.
Published: December 2002

Overexpression of Bcl-2 is a potential mechanism for chemoresistance in acute leukemia and has been associated with unfavorable clinical outcome. We hypothesized that down-regulation of Bcl-2 would restore chemosensitivity in leukemic cells. To test this hypothesis, we performed a phase 1 study of G3139 (Genasense, Genta, Berkeley Heights, NJ), an 18-mer phosphorothioate Bcl-2 antisense, with fludarabine (FL), cytarabine (ARA-C), and granulocyte colony-stimulating factor (G-CSF) (FLAG) salvage chemotherapy in patients with refractory or relapsed acute leukemia. Twenty patients with refractory or relapsed acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL) were enrolled. G3139 was delivered by continuous infusion on days 1 to 10. FLAG chemotherapy was administered on days 5 to 10. Common side effects of this combination included fever, nausea, emesis, electrolyte imbalance, and fluid retention that were not dose limiting. Plasma pharmacokinetics of G3139 demonstrated steady-state concentration (Css) within 24 hours. Of the 20 patients, 9 (45%) had disease response, 6 (5 AML, 1 ALL) with complete remission (CR) and 3 (2 AML and 1 ALL) with no evidence of disease but failure to recover normal neutrophil and/or platelet counts or to remain in remission for at least 30 days (incomplete remission). Bcl-2 mRNA levels were down-regulated in 9 of the 12 (75%) evaluable patients. This study demonstrates that G3139 can be administered safely with FLAG chemotherapy and down-regulate its target, Bcl-2. The encouraging clinical and laboratory results justify the current plans for a phase 3 study in previously untreated high-risk AML (ie, age at least 60 years).