bluuebunny/crossref_metadata_2025 huggingface dataset:
Transgenic mice that express Cre recombinase in osteoclasts
Authors: Chiu W.S.M. , McManus J.F. , Notini A.J. , Cassady A.I. , Zajac J.D. , Davey R.A.
Published: July 2004

To study the physiological control of osteoclasts, the bone resorbing cells, we generated transgenic mice carrying the Cre recombinase gene driven by either the tartrate‐resistant acid phosphatase (TRAP) or cathepsin K (Ctsk) promoters. TRAP‐Cre and Ctsk‐Cre transgenic mouse lines were characterized by breeding with LacZ ROSA 26 (R26R) reporter mice and immunohistochemistry for Cre recombinase. The Cre transgene was functional in all lines, with Cre‐mediated recombination occurring primarily in the long bones, vertebrae, ribs, and calvaria. Histological analyses of the bones demonstrated that functional Cre protein was present in 1) osteoclasts (Ctsk‐Cre); 2) osteoclasts, columnar proliferating, and hypertrophic chondrocytes (TRAP‐Cre line 4); and 3) round proliferating chondrocytes (TRAP‐Cre line 3). In conclusion, we generated transgenic mouse lines that will enable the deletion of floxed target genes in osteoclasts, which will be valuable tools for studying the regulation of osteoclast function. genesis 39:178–185, 2004. © 2004 Wiley‐Liss, Inc.
Nuclear β‐catenin‐dependent Wnt8 signaling in vegetal cells of the early sea urchin embryo regulates gastrulation and differentiation of endoderm and mesodermal cell lineages
Authors: Wikramanayake Athula H. , Peterson Robert , Chen Jing , Huang Ling , Bince Joanna M. , McClay David R. , Klein William H.
Published: July 2004

The entry of β‐catenin into vegetal cell nuclei beginning at the 16‐cell stage is one of the earliest known molecular asymmetries seen along the animal–vegetal axis in the sea urchin embryo. Nuclear β‐catenin activates a vegetal signaling cascade that mediates micromere specification and specification of the endomesoderm in the remaining cells of the vegetal half of the embryo. Only a few potential target genes of nuclear β‐catenin have been functionally analyzed in the sea urchin embryo. Here, we show that SpWnt8, a Wnt8 homolog from Strongylocentrotus purpuratus, is zygotically activated specifically in 16‐cell‐stage micromeres in a nuclear β‐catenin‐dependent manner, and its expression remains restricted to the micromeres until the 60‐cell stage. At the late 60‐cell stage nuclear β‐catenin‐dependent SpWnt8 expression expands to the veg2 cell tier. SpWnt8 is the only signaling molecule thus far identified with expression localized to the 16–60‐cell stage micromeres and the veg2 tier. Overexpression of SpWnt8 by mRNA microinjection produced embryos with multiple invagination sites and showed that, consistent with its localization, SpWnt8 is a strong inducer of endoderm. Blocking SpWnt8 function using SpWnt8 morpholino antisense oligonucleotides produced embryos that formed micromeres that could transmit the early endomesoderm‐inducing signal, but these cells failed to differentiate as primary mesenchyme cells. SpWnt8‐morpholino embryos also did not form endoderm, or secondary mesenchyme‐derived pigment and muscle cells, indicating a role for SpWnt8 in gastrulation and in the differentiation of endomesodermal lineages. These results establish SpWnt8 as a critical component of the endomesoderm regulatory network in the sea urchin embryo. genesis 39:194–205, 2004. © 2004 Wiley‐Liss, Inc.
Realistic spatial sampling for MEG beamformer images
Authors: Barnes Gareth R. , Hillebrand Arjan , Fawcett Ian P. , Singh Krish D.
Published: July 2004

The spatial resolution achievable using magnetoencephalography (MEG) beamformer techniques is inhomogeneous across the brain and is related directly to the amplitude of the underlying electrical sources [Barnes and Hillebrand, Hum Brain Mapp 2003;18:1–12; Gross et al., Proc Natl Acad Sci USA 2001;98:694–699; Van Veen et al., IEEE Trans Biomed Eng 1997;44:867–860; Vrba and Robinson, Proc 12th Int Conf Biomagn 2001]. We set out to examine what an adequate level of spatial sampling of the brain volume is in a realistic situation, and what implications these inhomogeneities have for region‐of‐interest analysis. As a basis for these calculations, we used a simple retinotopic mapping experiment where stimuli were 17‐Hz reversing gratings presented in either left or right visual hemifield. Beamformer weights were calculated based on the covariance of the MEG data in a 0–80 Hz bandwidth. We then estimated volumetric full‐width half‐maximum (FWHM) maps at a range of sampling levels. We show that approximately 10% of the 1 mm cubic voxels in the occipital volume have a FWHM smoothness of <5 mm, and 80% <10 mm in three subjects. This was despite relatively low mean signal‐to‐noise ratios (SNR) values of 1.5. We demonstrate how visualization of these FWHM maps can be used to avoid some of the pitfalls implicit in beamformer region‐of‐interest analysis. Hum. Brain Mapping 23:120–127, 2004. © 2004 Wiley‐Liss, Inc.
Neural systems for sign language production: Mechanisms supporting lexical selection, phonological encoding, and articulation
Authors: San José‐Robertson Lucila , Corina David P. , Ackerman Debra , Guillemin Andre , Braun Allen R.
Published: July 2004

Overt production of ASL signs was evaluated using H215O PET to differentiate brain systems that support sign language production at the lexical‐selection and phonological‐articulatory levels. Subjects were 16 right‐handed, congenitally deaf native ASL signers (10 women, six men; age 20 to 29 years). Scans were performed while subjects (1) passively viewed ASL nouns, (2) repeated nouns, (3) generated verbs in response to these nouns, (4) passively viewed videotaped segments depicting transitive actions, and (5) generated a verb to describe these actions. Conjunctions between the two verb‐generation tasks revealed left‐lateralized activation of perisylvian, frontal, and subcortical regions commonly observed in spoken language generation tasks and implicated in processes of semantic feature binding and lexical selection. Analysis of noun repetition minus viewing condition revealed activation of distinct systems supporting phonological encoding and articulation, including bilateral activation of sensorimotor areas and association cortices in the temporal, parietal, and occipital lobes. In addition, lexical‐selection and articulatory processes were associated with activation of different corticostriatal‐thalamocortical circuits: articulation with activation of the motor, and lexical‐selection with activation of the prefrontal circuits, respectively. The results collectively provide insight into dissociable neural systems underlying these psycholinguistic functions. In addition, activation of regions that are typically associated with the auditory system during sign production suggests that these regions may support modality‐independent linguistic processes, or may indicate cross‐modal plasticity within the deaf brain. Hum Brain Mapp 23:156–167, 2004. Published 2004 Wiley‐Liss, Inc.
“Aha!” effects in a guessing riddle task: An ERP study
Authors: Mai Xiao‐Qin , Luo Jing , Wu Jian‐Hui , Luo Yue‐Jia
Published: July 2004

In the August 2004 issue of Human Brain Mapping, it should have been noted that Drs. Yue‐Jia Luo and Jing Luo contributed equally to their ERP study of “Aha!” effects in a guessing riddle task [Hum Brain Mapp 22(4):261–270]. Correspondence should be addressed to Dr. Yue‐Jia Luo at luoyj@psych.ac.cn. Hum Brain Mapp 23:128, 2004. © 2004 Wiley‐Liss, Inc.
Effects of NQO1 deficiency on levels of cyclopurines and other oxidative DNA lesions in liver and kidney of young mice
Authors: Zhou Guo‐Dong , Randerath Kurt , Donnelly Kirby C. , Jaiswal Anil K.
Published: July 2004

I‐compounds are bulky indigenous DNA adducts that can be detected by 32P‐postlabeling. A subgroup, termed type II I‐compounds, represents DNA lesions induced by oxidative stress. Several major type II I‐compounds have been identified as dinucleotides containing 3′‐terminal 8,5′‐cyclo‐2′‐deoxyadenosine (cA). Levels of type II I‐compounds depend on the pro‐oxidant status of the cell. For example, enhanced formation of such oxidative DNA lesions in newborn rodents appears to be a consequence of incomplete development of neonatal antioxidant defense systems. We tested the hypothesis that young mice deficient in NAD(P)H:quinone oxidoreductase 1 (NQO1), an antioxidant enzyme catalyzing the detoxification of quinones and their derivatives, show increased formation of these oxidative DNA lesions. Type II I‐compound levels were determined by 32P‐postlabeling in liver and kidney DNA of untreated male wild‐type or NQO1‐null C57BL/6 mice of different ages. NQO1 catalytic activities and contents were measured by spectrophotometric and Western blotting techniques, respectively. Elevated oxidative adduct levels including those containing cA were detected in NQO1‐null compared to wild‐type mice at 10, 30 and 90 days in liver and at 30 and 90 days in kidney DNA. Furthermore, there were statistically significant inverse relationships between type II I‐compound levels and NQO1 activities in wild‐type mice up to 30 days of age. Taken together, the results suggest that NQO1 plays an important role in attenuating endogenous oxidative DNA damage in vivo. Our results show also that type II I‐compounds represent useful and sensitive biomarkers with utility in studies of oxidative DNA damage and its consequences. © 2004 Wiley‐Liss, Inc.
The role of fibroblasts in the modulation of integrin‐dependent interactions between the gastric cell line HGT‐1 and fibronectin
Authors: Nejjari Mimoun , Anderson Wena , Pourreyron Céline , Jacquier Marie‐France , Scoazec Jean‐Yves , Remy Lionel
Published: July 2004

Fibronectin plays an important role in gastric cancer progression. However, little is known about the microenvironmental factors modulating integrin‐dependent interactions between gastric cancer cells and fibronectin. We therefore studied the regulation by fibroblasts of the integrin‐dependent adhesion and migration of the gastric cancer cell line HGT‐1 onto fibronectin. We first determined, by immunofluorescence, immunoblotting and flow cytometry, that HGT‐1 cells expressed α3, α5, α6, αV and β1 integrin chains, and the αVβ3 and αVβ5 dimers. We verified that HGT‐1 cells xenografted to the immunosuppressed newborn rat retained the integrin repertoire detected in vitro and were able to induce the formation of tumors rich in fibronectin. By using an in vitro assay in the presence of neutralizing antibodies, we verified that HGT‐1 adhesion and migration onto fibronectin involved β1, αV and α5 integrin chains; we verified, by using an in situ adhesion test to rat gastric wall frozen sections, that in situ HGT‐1 adhesion to fibronectin was integrin dependent. In coculture experiments, we showed that organ‐specific fibroblasts from stomach, lung and dermis were able to induce, in a site‐specific manner, the expression of β1, α5 and αV integrin chains in HGT‐1 cells, their integrin‐dependent adhesion and migration on fibronectin and their capacity to secrete oncofetal fibronectin. In conclusion, our results show the capacity for tissue‐derived fibroblasts to modulate the integrin‐dependent interactions between the gastric cell line HGT‐1 and fibronectin. They strongly suggest that, in gastric cancer, stromal fibroblasts contribute to promote fibronectin‐mediated local invasion by tumor cells. © 2004 Wiley‐Liss, Inc.
Potential of human γδ T lymphocytes for immunotherapy of cancer
Authors: Kabelitz Dieter , Wesch Daniela , Pitters Elke , Zöller Margot
Published: July 2004

T lymphocytes are classified into 2 subsets based on their T‐cell receptor (TCR) expression. The vast majority of T cells expresses an αβ TCR heterodimer. These αβ T cells recognize antigenic peptides presented by MHC class I (for CD8+ T cells) or MHC class II molecules (for CD4+ T cells). Concepts of cancer immunotherapy are mostly concerned with activation of these MHC‐restricted αβ T cells. Until recently, a numerically small subset of T cells, which expresses an alternative TCR composed of a CD3‐associated γδ heterodimer, has received far less attention as a potential agent in cancer therapy. These γδ T cells share with αβ T cells certain effector functions such as cytokine production and potent cytotoxic activity but recognize different sets of antigens, usually in a non‐MHC‐restricted fashion. Different subsets of human γδ T cells recognize stress‐inducible MHC class I‐related molecules frequently expressed on epithelial tumor cells or phosphorylated metabolites which can be generated by tumor cells. In line with this, many tumor cells are highly susceptible to γδ T‐cell mediated lysis. In our article, we summarize the available evidence for a contribution of human γδ T cells in tumor defense and discuss potential strategies for the immunotherapy of tumors based on the endogenous activation and/or adoptive transfer of tumor‐reactive γδ T lymphocytes. © 2004 Wiley‐Liss, Inc.
von Hippel‐Lindau tumor suppressor protein stimulation by thrombin involves RhoA activation
Authors: Turcotte Sandra , Desrosiers Richard R. , Brand Geneviève , Béliveau Richard
Published: July 2004

Inactivation of the von Hippel‐Lindau (VHL) tumor suppressor gene is associated with the development of vascular tumors including renal cell carcinoma. Aside from the role played by the VHL protein (pVHL) in negative regulation of hypoxia‐inducible factor, 41F‐1α, pVHL also takes part in cytoskeletal organization. Thrombin is a serine protease involved in angiogenesis and in cancer progression and its action is mediated by the protease‐activated receptors (PARs). In several cell types, thrombin induces reorganization of the cytoskeleton along with RhoA activation. Thus, we conducted an investigation on the capacity of thrombin to regulate pVHL expression. Our results demonstrated that VHL mRNA and protein levels were increased by thrombin in cultured renal cancer cells. Cytoplasmic pVHL was redistributed to perinuclear regions and membrane fractions following thrombin treatments. Stimulation of Caki‐1 cells with PAR1, PAR2 and PAR4 agonist peptides demonstrated that PAR1 was the receptor involved in thrombin‐induced pVHL expression. Western blot analysis confirmed that these cells express PAR1 and that its expression was increased by thrombin. PAR1 activation by both thrombin and an agonist peptide stimulated renal cancer cell invasion through Matrigel. Interestingly, the upregulation of pVHL was dependent on RhoA because C3 exotoxin abolished pVHL induction. However, the pharmacological Rho kinase inhibitor, Y27632, did not influence pVHL expression in the presence of thrombin, suggesting that other RhoA effectors were involved in the process. Together, these results demonstrate that thrombin induces both pVHL expression via PAR1/RhoA activation as well as the stimulation of renal cancer cell invasion suggesting a role for thrombin in tumor invasion. © 2004 Wiley‐Liss, Inc.
Artificial ultraviolet radiation and ocular melanoma in Australia
Authors: Vajdic Claire M. , Kricker Anne , Giblin Michael , Mckenzie John , Aitken Joanne F. , Giles Graham G. , Armstrong Bruce K.
Published: July 2004

We examined risk of ocular melanoma with exposure to artificial sources of exposure to ultraviolet radiation (UVR) in a population‐based epidemiologic study of 290 cases of ocular melanoma and 893 controls aged 18–79 years in Australia in 1996–1998. Cases were identified through a prospective survey of all ophthalmologists and cancer registries in Australia; 91.8% participated. Controls were sourced from electoral rolls; 67.4% of those who were eligible and contactable participated, while 27.3% could not be contacted. Exposure to welding and use of sunlamps, including sunbeds and tanning booths, was measured by telephone interview. Analyses used unconditional logistic regression and included age, sex, region of birth, eye color, ocular and cutaneous sun sensitivity and personal sun exposure as covariates. Risk of choroid and ciliary body melanoma in 246 cases increased significantly with longer duration of use of sunlamps, first use before 21 years of age and first use after 1980. These effects were independent of personal sun exposure. Risk of these melanomas also increased with increasing duration of welding exposure, although the trend was not significant overall. There was no evidence that these exposures increased the risk of iris (n = 25) or conjunctival (n = 19) melanomas. Personal exposure to sunlamps and welding predicts risk of choroid and ciliary body melanoma in Australia. © 2004 Wiley‐Liss, Inc.
Association of lipoprotein lipase gene polymorphism with risk of prostate cancer in a japanese population
Authors: Narita Shintaro , Tsuchiya Norihiko , Wang Lizhong , Matsuura Shinobu , Ohyama Chikara , Satoh Shigeru , Sato Kazunari , Ogawa Osamu , Habuchi Tomonori , Kato Tetsuro
Published: July 2004

A high fat intake has been associated with prostate cancer risk, and gene polymorphisms of lipoprotein lipase (LPL) play an important role in plasma lipoprotein metabolism. We herein analyzed the association of LPL gene polymorphisms with the risk of prostate cancer in a Japanese population. Three single nucleotide polymorphisms (SNPs) of LPL designated as Ser447stop, HindIII and PvuII were genotyped by the polymerase chain reaction‐restriction fragment length polymorphism method in 273 prostate cancer patients, 205 benign prostatic hyperplasia (BPH) patients and 230 male controls. The men with the CG + GG genotypes of the Ser447stop polymorphism had an increased risk of prostate cancer compared to those with the CC genotype [age‐adjusted odds ratio (aOR) = 1.625; 95% CI = 1.068–2.471; p = 0.023]. Furthermore, the increased risk associated with the CG + GG genotypes was more strongly observed in patients with high‐grade cancers (aOR = 2.843; 95% CI = 1.252–6.458; p = 0.039) or metastatic diseases (aOR = 2.300; 95% CI = 1.042–5.074; p = 0.013), whereas the risk was not significant in those with low‐ to intermediate‐grade cancers or nonmetastatic diseases. In the HindIII and PvuII polymorphisms, there was no significant difference between the prostate cancer patients and the controls, and no significant results as for tumor grade and stage. None of the 3 polymorphisms showed any association with the risk of BPH. Our results suggest that the LPL Ser447stop polymorphism is a common genetic modifier for the development of prostate cancer, particularly that of high‐grade and/or high‐stage, in a Japanese population. © 2004 Wiley‐Liss, Inc.
Type‐specific associations of human papillomavirus load with risk of developing cervical carcinoma in situ
Authors: Moberg Martin , Gustavsson Inger , Gyllensten Ulf
Published: July 2004

We have previously shown that high human papillomavirus (HPV) 16 load in Papanicolaou smears negative for dysplasia is strongly associated with risk for carcinoma in situ (CIS) of the cervix. Here we study the amount of HPV DNA for some of the most frequent high‐risk HPV types as determinants of progression to cervical CIS. Real‐time PCR is used to estimate the normalized viral load of HPV 16, 18, 31, 33, 35, 39, 45, 52, 58 and 67 in 457 cases of cervical CIS and 552 matched population controls. A total of 2,747 archival Pap smears from gynecologic health examinations, collected over a period of up to 26 years, were analyzed to assess viral load during the infection history. Cervical smear samples differ widely in amount of DNA, underscoring the need for normalization of HPV load to number of cells in the sample. The risk of developing cervical CIS increases with higher viral load for most of the HPV types studied. The range of copy numbers per cell does not differ between HPV types but the odds ratio for CIS in the percentile with highest viral load is substantially higher for HPV 16 (OR = 36.9; 95% CI = 8.9–153.2) than for HPV 31 (OR = 3.2; 95% CI = 1.1–9.1) or HPV 18/45 (OR = 2.6; 95% CI = 1.0–6.4). Therefore, HPV viral load may be predictive of future risk of cervical CIS at a stage when smears are negative for squamous abnormalities, but differences between HPV types need closer attention. © 2004 Wiley‐Liss, Inc.
Ethanol‐induced in vitro invasion of breast cancer cells: The contribution of MMP‐2 by fibroblasts
Authors: Aye Moe Moe , Ma Cuiling , Lin Hong , Bower Kimberly A. , Wiggins Richard C. , Luo Jia
Published: July 2004

Ethanol is a tumor promoter and may promote metastasis of breast cancer. However, the underlying cellular/molecular mechanisms remain unknown. Overexpression and high activity of matrix metalloproteinase‐2 (MMP‐2) are frequently associated with metastatic breast cancers and serve as a prognostic indicator of clinical outcome. MMP‐2 is predominantly expressed in stromal fibroblasts and plays a pivotal role in regulating the invasive behavior of breast tumor cells. We hypothesized that ethanol may enhance the invasion of breast tumor cells by modulating the activity of fibroblastic MMP‐2. With in vitro models (HS68 and CCD1056SK human fibroblasts), we showed that ethanol at physiologically relevant concentrations (50–200 mg/dl) activated MMP‐2; conversely, at a higher concentration (400 mg/dl), it inhibited the MMP‐2 activity. Consistently, conditioned medium collected from ethanol (50–200 mg/dl)‐exposed fibroblasts markedly enhanced the invasive potential of breast cancer cells and mammary epithelial cells overexpressing ErbB2/HER2 (BT474, SKBR‐3 and HB2ErbB2 cells) but had little effect on cells with low ErbB2 levels (BT20 and HB2 cells). In contrast, conditioned medium obtained from ethanol (400 mg/dl)‐treated fibroblasts inhibited cell invasion. Selective inhibitors of MMP‐2 (SB‐3CT and OA‐Hy) eliminated ethanol‐stimulated invasion, indicating that the effect of ethanol was mediated by MMP‐2. Ethanol activated conventional PKCs and JNKs in fibroblasts; inhibitors of PKC (Go6850 and Go6976) and JNKs (SP600125) significantly inhibited ethanol‐mediated MMP‐2 activation as well as cell invasion, indicating that PKCs and JNKs play a role in ethanol‐induced MMP‐2 activation and cell invasion in vitro. Thus, ethanol‐promoted breast cancer cell invasion may be mediated by the modulation of fibroblastic MMP‐2. © 2004 Wiley‐Liss, Inc.
Use of soil‐water balance components to assess yield of groundnut and sunflower under a high water table situation
Authors: Das Madhumita
Published: July 2004

This study aimed to evaluate the effect of water input on the yield of groundnut and sunflower grown by supplying irrigation under high water table conditions (1.2–1.75 m from the surface). Crop yield with respect to net irrigation depth and upward flux from the water table, and contribution of irrigation and groundwater to yield reveal that 4 or 6 cm water at 0.9 net irrigation (IW)/cumulative pan evaporation (CPE), and 4 or 5 cm water at 7 days interval and at 0.7 or 1.0 IW/CPE, are the suitable levels of irrigation for growing groundnut and sunflower respectively. The yield response to evapotranspiration (ET) was linear, while it was curvilinear with irrigation depth (IW). It was also curvilinear, that is quadratic, with IW in conjunction with downward drainage loss (D) in groundnut, and with D and upward flux (U) in both the crops. Consequent upon the precise estimate of predictive yield output, the functions developed for groundnut separately with ET, IW, D, IW with D, and D and U, and in sunflower, functions established by using ET or IW alone and in alliance with D and U, were found as best‐fit functions. The best‐fit functions offer some tools to be exploited for efficient utilization of irrigation water with respect to groundwater contribution towards maximum yield benefit of groundnut and sunflower grown on sandy loam to sandy clay loam Aeric Haplaquepts soil. Copyright © 2004 John Wiley & Sons, Ltd.
Molecular orientation of ultrahigh molecular weight polyethylene induced by various sliding motions
Authors: Sambasivan Sharadha , Fischer Daniel A. , Shen Ming C. , Hsu Stephen M.
Published: July 2004

Wear and wear debris of ultrahigh molecular weight polyethylene (UHMWPE) in joint replacements have been recognized as one of the major contributors to the failure of orthopedic implants. The detailed wear mechanism of polyethylene under biomechanic motions is not well understood. In simulation wear bench tests, it was found that unidirectional sliding produces the least amount of wear, reciprocating motion increases wear significantly, and cross‐shear motion (similar to hip and knee joint motion in the human body) produces the highest amount of wear. Conventional wear theories are inadequate to explain this observation. This study utilizes resonant absorption of linearly polarized soft X‐rays at a synchrotron radiation beam line to measure the molecular orientation of a UHMWPE surface layer subjected to different wear motions. Carbon‐K‐edge partial‐electron‐yield X‐ray absorption measurements were done on the worn UHMWPE samples. X‐ray absorption measurements show conclusively that the molecular chains of UHMWPE align preferentially parallel to the direction of sliding. Examination under various wear motions showed that unidirectional shear produced the maximum chain orientation, whereas cross‐shear wear motions produced the least amount of orientation. When polymeric chains align, the surface layer tends to be more brittle and hard, thus resisting wear. When they do not align, loose chains may be subjected to both Mode I and Mode II fracture, hence increasing the wear rate. This molecular alignment observation may offer an explanation of why different wear motions have different wear characteristics. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 70B: 278–285, 2004
Removal of cupric ions from acidic sulfate solution using reticulated vitreous carbon rotating cylinder electrodes
Authors: Reade Gavin W , Nahle Ayssar H , Bond Peter , Friedrich Jens M , Walsh Frank C
Published: July 2004

The potentiostatic deposition of copper from acid sulfate solutions (0.50 mol dm−3 Na2SO4 at pH 2 and 298 K) was studied at four porosity grades (10, 30, 60 and 100 pores per linear inch, ppi) of reticulated vitreous carbon (RVC) rotating cylinder electrode (RCE). The rate of removal of cupric ions from a 200 cm3 volume of electrolyte was examined as a function of the grade of RVC foam, the electrode potential and the initial cupric ion concentration. For the 100 ppi material, the product of the mass transport coefficient and the electroactive area per unit volume of electrode (kmAe) was equal to 0.28 s−1 at a potential of −500 mV vs SCE for an initial cupric ion concentration of 0.85 mmol dm−3 and a constant rotation speed of 1500 rev min−1. Under the experimental conditions, an initial dissolved copper concentration of 63.5 ppm could be reduced to <0.1 ppm in approximately 60 min using a 100 ppi RVC RCE. SEM studies showed some non‐uniform deposition of metal due to heterogeneous nucleation of copper together with the development of rough deposits. Copyright © 2004 Society of Chemical Industry
Borate–nucleotide complex formation depends on charge and phosphorylation state
Authors: Kim Danny H. , Faull Kym F. , Norris Andrew J. , Eckhert Curtis D.
Published: July 2004

Flow injection analysis with electrospray ionization mass spectrometry was used to investigate borate–nucleotide complex formation. Solutions containing 100 µM nucleotide and 500 µM boric acid in water–acetonitrile–triethylamine (50 : 50 : 0.2, v/v/v; pH 10.3) showed that borate complexation with nicotinamide nucleotides was significantly influenced by the charge on the nicotinamide group and the number of phosphate groups on the adenine ribose. Borate binding decreased in the order of NAD+, NADH, NADP+ and NADPH. To investigate the relationship between complex formation and phosphorylation, association constants (KA) of borate–adenine (AMP, ADP, ATP), –guanine (GMP, GDP, GTP), –cytidine (CMP, CDP, CTP) and –uridine (UMP, UDP, UTP) complexes were compared. The results showed that the number of nucleotide phosphate groups was inversely proportional to the relative abundance of the borate complexes, with the KA of borate–nucleotide complex decreasing in the order mono‐, di‐ and tri‐phosphates (AMP ≈ GMP ≈ CMP ≈ UMP > ADP ≈ GDP ≈ CDP ≈ UDP > GTP > ATP ≈ CTP ≈ UTP). At pH 7.4, using ammonium bicarbonate buffer, only borate–NAD+ complex was observed. This indicates that the borate–NAD+ complex may be the most physiologically relevant of those studied. Copyright © 2004 John Wiley & Sons, Ltd.
Identification of low molecular weight proteins isolated by 2‐D liquid separations
Authors: Zhu Kan , Miller Fred R. , Barder Timothy J. , Lubman David M.
Published: July 2004

Proteins with molecular mass (Mr) <20 kDa are often poorly separated in 2‐D sodium dodecyl sulfate polyacrylamide gel electrophoresis. In addition, low‐Mr proteins may not be readily identified using peptide mass fingerprinting (PMF) owing to the small number of peptides generated in tryptic digestion. In this work, we used a 2‐D liquid separation method based on chromatofocusing and non‐porous silica reversed‐phase high‐performance liquid chromatography to purify proteins for matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometric (MALDI‐TOFMS) analysis and protein identification. Several proteins were identified using the PMF method where the result was supported using an accurate Mr value obtained from electrospray ionization TOFMS. However, many proteins were not identified owing to an insufficient number of peptides observed in the MALDI‐TOF experiments. The small number of peptides detected in MALDI‐TOFMS can result from internal fragmentation, the few arginines in its sequence and incomplete tryptic digestion. MALDI‐QTOFMS/MS can be used to identify many of these proteins. The accurate experimental Mr and pI confirm identification and aid in identifying post‐translational modifications such as truncations and acetylations. In some cases, high‐quality MS/MS data obtained from the MALDI‐QTOF spectrometer overcome preferential cleavages and result in protein identification. Copyright © 2004 John Wiley & Sons, Ltd.
Electron ionization‐induced fragmentation of N‐ and O‐alkoxymethylated carbostyril and phenanthridinone
Authors: Szmigielski Rafał , Danikiewicz Witold
Published: July 2004

Unimolecular fragmentation patterns of N‐alkoxymethylated carbostyril and phenanthridinone and their O‐alkoxymethyl isomers were studied. The main fragmentation reaction observed for the studied compounds is the elimination of an aldehyde molecule. The main products of this reaction are the appropriate N‐methyl derivatives, but ions with other structures are also formed. This reaction is supposed to proceed via 1,3‐H shift in the alkoxymethyl group in the case of the N‐alkoxymethyl derivatives and by a multi‐step mechanism for O‐alkoxymethylated compounds. Another important fragmentation common for all studied compounds is the loss of an alkyl radical from N‐ and O‐alkoxymethyl groups, yielding the appropriate stable isomeric cations, which, according to the results of the further fragmentation, undergo fast equilibration reaction via an ion–neutral complex. This process is accompanied by the unusually high kinetic energy release value. Copyright © 2004 John Wiley & Sons, Ltd.
Fragmentation study of peptide acetals and aldehydes using in‐source collision‐induced dissociation
Authors: Buré Corinne , Falher Guy Le , Lange Catherine , Delmas Agnès
Published: July 2004

The fragmentation of peptide acetals and peptide diols, corresponding to the hydrated form of the peptide aldehyde, is dominated by the successive losses of two molecules of MeOH and water, respectively. Using model peptides, the fragmentation mechanism, with respect to the loss of methanol and water, was elucidated. The first loss was certainly charge‐directed whereas the second probably occurred via the nucleophilic attack of the nitrogen of an amine on the C‐terminal carbon leading to a cyclic ion. Copyright © 2004 John Wiley & Sons, Ltd.
Repeated contact with subtoxic soman leads to synaptic vulnerability in hippocampus
Authors: Munirathinam Subramani , Bahr Ben A.
Published: July 2004

Soman, an anticholinesterase and dangerous nerve agent, produces convulsions, memory impairment, and cell loss in the brain, especially in the hippocampus. Soman‐induced accumulation of acetylcholine initiates mechanisms responsible for the development of incapacitating seizures. The prolonged epileptiform nature of these seizures causes the release of another excitatory neurotransmitter, glutamate, which has been linked to the toxic action of the nerve agent. Here, we tested whether subtoxic soman exposures influence the brain's sensitivity to glutamate‐based excitotoxicity. Over a 1‐week period, hippocampal slice cultures were exposed daily to a transient level of soman that produced no evidence of synaptic deterioration. After the subtoxic soman treatments, however, the tissue became vulnerable to a brief episode of glutamate receptor overstimulation that normally resulted in little or no excitotoxic damage. In those slice cultures treated with subtoxic soman, a decline in synaptic markers as well as an increase in spectrin breakdown occurred 24 hr after the mild excitotoxic event. Exposure to high soman concentrations alone produced similar synaptic degeneration, but without evident cell death, suggesting that synaptic decline is an early neurotoxicological response to the nerve agent. Interestingly, enhanced excitotoxic sensitivity caused the brain tissue to become susceptible to disparate insults initiated before or after the soman contact. These findings indicate that seemingly innocuous soman exposures leave the hippocampus sensitive to the types of insults implicated in traumatic brain injury and stroke. They also warn that asymptomatic contact with soman may lead to progressive synaptopathogenesis and that early indicators of soman exposure are critical to prevent potential brain injury. © 2004 Wiley‐Liss, Inc.
Fine structure of degeneration in the cochlear nucleus of the chinchilla after acoustic overstimulation
Authors: Kim J.J. , Gross J. , Potashner S.J. , Morest D.K.
Published: July 2004

To study plastic changes in the cochlear nucleus after acoustic stimulation, adult chinchillas were exposed once to a 4‐kHz octave‐band noise at 108 dB SPL for 3 hr. After survival times of 1, 2, 4, 8, and 16 weeks, samples were taken for electron microscopy from a part of the cochlear nucleus, where cochlear nerve fibers degenerated after the noise exposure. Progressive changes in fine structure were characterized as early, intermediate, and late stages of degeneration. Freshly occurring synaptic degeneration appeared in each period from 1–16 weeks. Endings with large round vesicles, putative excitatory synapses of the cochlear nerve, displayed progressive increases in neurofilaments and enlarged synaptic vesicles. Compared to controls, synaptic vesicles seemed fewer, often in small clusters in the interior of endings, and smaller in the synaptic zone. These early changes progressed to mitochondrial disintegration and overt “watery” degeneration. Some surviving endings, however, were shrunken and displaced partially by enlarged spaces in the synaptic complex. Dense‐cored vesicles gathered in these endings. In terminals with pleomorphic and flattened vesicles, presumed inhibitory endings, cytological changes appeared within 1 week and persisted for months. The synaptic endings darkened, some vesicles disintegrated, and many smaller flatter vesicles collapsed into heaps. Especially at the presynaptic membrane, vesicles were shriveled, but a few mitochondria were preserved. Without overt signs of synaptic degeneration, some of these cytological changes presumably reflect reduced synaptic activity in the inhibitory endings. These changes may contribute to a continuing process associated with abnormal auditory functions, including hyperacusis and tinnitus. © 2004 Wiley‐Liss, Inc.
Calendar year age estimates of Allerød–Younger Dryas sea‐level oscillations at Os, western Norway
Authors: Lohne Øystein S. , Bondevik Stein , Mangerud Jan , Schrader Hans
Published: July 2004

A detailed shoreline displacement curve documents the Younger Dryas transgression in western Norway. The relative sea‐level rise was more than 9 m in an area which subsequently experienced an emergence of almost 60 m. The sea‐level curve is based on the stratigraphy of six isolation basins with bedrock thresholds. Effort has been made to establish an accurate chronology using a calendar year time‐scale by 14C wiggle matching and the use of time synchronic markers (the Vedde Ash Bed and the post‐glacial rise in Betula (birch) pollen). The sea‐level curve demonstrates that the Younger Dryas transgression started close to the Allerød–Younger Dryas transition and that the high stand was reached only 200 yr before the Younger Dryas–Holocene boundary. The sea level remained at the high stand for about 300 yr and 100 yr into Holocene it started to fall rapidly.

The peak of the Younger Dryas transgression occurred simultaneously with the maximum extent of the ice‐sheet readvance in the area. Our results support earlier geophysical modelling concluding a causal relationship between the Younger Dryas glacier advance and Younger Dryas transgression in western Norway. We argue that the sea‐level curve indicates that the Younger Dryas glacial advance started in the late Allerød or close to the Allerød–Younger Dryas transition. Copyright © 2004 John Wiley & Sons, Ltd.
A major widespread climatic change around 5300 cal. yr BP at the time of the Alpine Iceman
Authors: Magny Michel , Haas Jean Nicolas
Published: July 2004

Palaeoenvironmental and archaeological data from Arbon Bleiche, Lake Constance (Switzerland) give evidence of a rapid rise in lake‐level dated by tree‐ring and radiocarbon to 5320 cal. yr BP. This rise event was the latest in a series of three successive episodes of higher lake‐level between 5550 and 5300 cal. yr BP coinciding with glacier advance and tree‐limit decline in the Alps. This west‐central European climate change may have favoured the quick burial and the preservation of the Alpine Iceman recently found in the Tyrolean Alps. It has possible equivalents in many records from various regions in both hemispheres dating to 5600–5000 cal. yr BP and corresponds to global cooling and contrasting patterns of hydrological changes. This major mid‐Holocene climate event marks the Hypsithermal/Neoglaciation transition possibly resulting from a combination of different factors including orbital forcing, changes in ocean circulation and variations in solar activity. Copyright © 2004 John Wiley & Sons, Ltd.
Fluvial system response to Late Devensian (Weichselian) aridity, Baston, Lincolnshire, England
Authors: Briant Rebecca M. , Coope G. Russell , Preece Richard C. , Keen David H. , Boreham Steve , Griffiths Huw I. , Seddon Mary B. , Gibbard Philip L.
Published: July 2004

Little is known about the impact of Late Devensian (Weichselian) aridity on lowland British landscapes, largely because they lack the widespread coversand deposits of the adjacent continent. The concentration of large interformational ice‐wedge casts in the upper part of many Devensian fluvial sequences suggests that fluvial activity may have decreased considerably during this time. The development of optically stimulated luminescence (OSL) dating enables this period of ice‐wedge cast formation to be constrained for the first time in eastern England, where a marked horizon of ice‐wedge casts is found between two distinctive dateable facies associations. Contrasts between this horizon and adjacent sediments show clear changes in environment and fluvial system behaviour in response to changing water supply, in line with palaeontological evidence. In addition to providing chronological control on the period of ice‐wedge formation, the study shows good agreement of the radiocarbon and OSL dating techniques during the Middle and Late Devensian, with direct comparison of these techniques beyond 15 000 yr for the first time in Britain. It is suggested that aridity during the Late Devensian forced a significant decrease in fluvial activity compared with preceding and following periods, initiating a system with low peak flows and widespread permafrost development. Copyright © 2004 John Wiley & Sons, Ltd.
Reinvestigation of the classic late‐glacial Bølling Sø sequence, Denmark: chronology, macrofossils, Cladocera and chydorid ephippia
Authors: Bennike Ole , Sarmaja‐Korjonen Kaarina , SeppÄnen Anna
Published: July 2004

The late‐glacial Bølling period was first identified by Johs. Iversen on the basis of pollen results from Lake Bølling Sø in Denmark. Because there were no radiocarbon dates from the sequence the Bølling Chronozone (12 000–13 000 14C yr BP) was later established on the basis of dates from other sites. A new project is reinvestigating the sediments from the Bølling Sø sequence with AMS radiocarbon dating and multiproxy analyses. Here we present results of AMS radiocarbon dating, macrofossil analyses, cladoceran analyses (Cladocera concentrations and chydorid ephippia) and Pediastrum analyses (concentrations). The AMS dates on land plant remains show that the lower part of the sequence is around 12 500 14C yr BP, and thus clearly pre‐dates the Allerød chronozone. However, construction of a chronology for the sequence was problematic, partly because of reworking of macroscopic plant remains. The climate ameliorated after glacial conditions to such an extent that growth of plants could begin at ca. 12 500 14C yr BP, but the results of multiproxy analyses show little evidence for a further warming period during the pre‐Allerød part of the sequence. Lake productivity was low, and tree birch rare or maybe absent. This may reflect widespread occurrence of dead ice, unstable soils, heavy in‐wash of minerogenic matter to the lake, resulting in turbid water and rapid sedimentation. The early pioneer vegetation was characterised by Salix polaris and Dryas octopetala, and by herbs. The Allerød Chronozone, and especially its initial part, appears to have been relatively warm but reduced cladoceran concentrations and increased proportion of chydorid ephippia suggest that climate cooled in the middle Allerød and that the late Allerød was colder than the early part. The early Younger Dryas was probably colder than the late Younger Dryas. Clear warming is apparent at the beginning of the Holocene, where the first macrofossil evidence of trees (Betula pubescens, Populus tremula) is found. Copyright © 2004 John Wiley & Sons, Ltd.
Surface exposure dating of the Great Aletsch Glacier Egesen moraine system, western Swiss Alps, using the cosmogenic nuclide 10Be
Authors: Kelly Meredith A. , Kubik Peter W. , Von Blanckenburg Friedhelm , SchlÜchter Christian
Published: July 2004

Egesen moraines throughout the Alps mark a glacial advance that has been correlated with the Younger Dryas cold period. Using the surface exposure dating method, in particular the measurement of the cosmogenic nuclide 10Be in rock surfaces, we attained four ages for boulders on a prominent Egesen moraine of Great Aletsch Glacier, in the western Swiss Alps. The 10Be dates range from 10 460±1100 to 9040±1020 yr ago. Three 10Be dates between 9630±810 and 9040±1020 yr ago are based upon samples from the surfaces of granite boulders. Two 10Be dates, 10 460±1100 and 9910±970 yr ago, are based upon a sample from a quartz vein at the surface of a schist boulder. In consideration of the numerous factors that can influence apparently young 10Be dates and the scatter within the data, we interpret the weighted mean of four boulder ages, 9640±430 yr (including the weighted mean of two 10Be dates of the quartz vein), as a minimum age of deposition of the moraine.

All 10Be dates from the Great Aletsch Glacier Egesen moraine are consistent with radiocarbon dates of nearby bog‐bottom organic sediments, which provide minimum ages of deglaciation from the moraine. The 10Be dates from boulders on the Great Aletsch Glacier Egesen moraine also are similar to 10Be dates from Egesen moraines of Vadret Lagrev Glacier on Julier Pass, in the eastern Swiss Alps. Both the morphology of the Great Aletsch Glacier Egesen moraine and the comparison with 10Be dates from the inner Vadret Lagrev Egesen moraine support the hypothesis that the climatic cooling that occurred during the Younger Dryas cold episode influenced the glacial advance that deposited the Great Aletsch Glacier Egesen moraine. Because of the large size and slow response time of Great Aletsch Glacier, we suggest that the Great Aletsch Glacier Egesen moraine was formed during the last glacial advance of the multiphased Egesen cold period, the Kromer stage, during the Preboreal chron. Copyright © 2004 John Wiley & Sons, Ltd.
Enrichment of the glycoalkaloids α‐solanine and α‐chaconine from potato juice by Adsorptive Bubble Separation using a pH gradient
Authors: Backleh Marlène , Ekici Perihan , Leupold Günther , Coelhan Mehmet , Parlar Harun
Published: July 2004

For the first time, the solanidine alkaloids α‐solanine and α‐chaconine could be quantitatively enriched from potato juice by Adsorptive Bubble Separation (ABS) with a pH gradient. The enrichment into the foam was influenced by the pH value, bubble size, and gas flow rate. The efficiency was highest on using diluted samples with a concentration between 2 and 6 mg L–1 of the alkaloids at pH 6.0. The experiments with a standard solution of each alkaloid confirmed that these substances can be quantitatively enriched into the ‘spumat’ without surface active potato proteins. The transfer into the foam fraction under these conditions was similar to that from the aqueous potato extract.
Exponential attractors for a singularly perturbed Cahn‐Hilliard system
Authors: Efendiev Messoud , Miranville Alain , Zelik Sergey
Published: July 2004

Our aim in this article is to give a construction of exponential attractors that are continuous under perturbations of the underlying semigroup. We note that the continuity is obtained without time shifts as it was the case in previous studies. Moreover, we obtain an explicit estimate for the symmetric distance between the perturbed and unperturbed exponential attractors in terms of the perturbation parameter. As an application, we prove the continuity of exponential attractors for a viscous Cahn‐Hilliard system to an exponential attractor for the limit Cahn‐Hilliard system. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An iterative procedure for solving a Cauchy problem for second order elliptic equations
Authors: Johansson Tomas
Published: July 2004

An iterative method for reconstruction of solutions to second order elliptic equations by Cauchy data given on a part of the boundary, is presented. At each iteration step, a series of mixed well‐posed boundary value problems are solved for the elliptic operator and its adjoint. The convergence proof of this method in a weighted L2 space is included. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Remark on the Hopf Bifurcation Theorem
Authors: Krasnosel'skii A. M. , Rachinskii D. I.
Published: July 2004

A simple generalization of the Hopf Bifurcation Theorem for scalar higher order ordinary differential equations is suggested. We study the degenerate case where several roots of the characteristic polynomial cross the imaginary axis at the same point for some value λ0 of the parameter λ. The main result is that if N1 roots cross the imaginary axis from the left to the right and N2 roots cross it from the right to the left, then λ0 is a Hopf bifurcation point whenever N1 ≠ N2. In particular, in the classical Hopf Bifurcation Theorem the numbers Nj are 0 and 1. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Natural history of posttraumatic cervical dystonia
Authors: Frei Karen P. , Pathak Mayank , Jenkins Stephen , Truong Daniel D.
Published: July 2004

We studied a case series of 9 patients with posttraumatic cervical dystonia, in whom involuntary muscle spasms and abnormal head postures occurred within 7 days after cervical injury. Patients were examined, treated with botulinum toxin as necessary, and were followed up to 5 years. Based on our observations of these cases, we propose that complex regional pain syndrome (CRPS) could represent a variant of posttraumatic cervical dystonia that may develop over time after the initiation of dystonia. © 2004 Movement Disorder Society