bluuebunny/crossref_metadata_2025 huggingface dataset:
Extra‐cellular thiol metabolism in clones of human metastatic melanoma with different gamma‐glutamyl transpeptidase expression: Implications for cell response to platinum‐based drugs
Authors: Paolicchi Aldo , Lorenzini Evelina , Perego Paola , Supino Rosanna , Zunino Franco , Comporti Mario , Pompella Alfonso
Published: November 2004

Thiol redox status can affect important functions both intracellularly and extracellularly. The plasma membrane enzyme γ‐glutamyl transpeptidase (GGT), which plays a crucial role in cellular handling of thiols, is often expressed in malignant tumors, including melanoma, although its expression levels may vary widely among different tumors or cells of the same tumor. In an attempt to better understand the functional significance of GGT overexpression, we have examined the relationships between intra‐ and extra‐cellular thiol metabolism and GGT expression. Intra‐ and extra‐cellular distribution of glutathione and other low mol. wt. thiols and disulfides was investigated in two different Me665/2 human melanoma clones that originated from the same metastasis, but exhibiting high (2/60 clone) and low (2/21 clone) GGT activity. Intracellular content of glutathione was lower in GGT‐rich 2/60 cells, in spite of high GGT expression. A lower utilization of extracellular cystine was also observed in these cells. In both clones, a direct secretion of cysteine in the extracellular medium was detected, which was independent of GGT‐mediated catabolism of extracellular glutathione. Substantial amounts of glutathione, GSSG and glutathione‐cysteine disulfide were accumulated extracellularly only in the case of GGT‐poor 2/21 cells, while the same event was apparent in 2/60 cells only after the following inhibition of GGT activity. When exposed to the trinuclear platinum compound BBR 3464 or hydrogen peroxide, which are very reactive for sulfur‐containing nucleophiles, the 2/60 clone showed higher sensitivity than the 2/21 clone to both agents. These results suggest that the clone‐specific balance between transport of sulfur aminoacids and GGT activity results in profound differences in the capability of each clone to modify the thiol redox status of the extracellular milieu. The finding may have important implications in tumor cell behavior with particular reference to chemosensitivity, since thiols are recognized factors in modulation of cell sensitivity to platinum‐based anticancer drugs. © 2002 Wiley‐Liss, Inc.
Identification of bradykinin receptors in clinical cancer specimens and murine tumor tissues
Authors: Wu Jun , Akaike Takaaki , Hayashida Kazuyuki , Miyamoto Yoichi , Nakagawa Takenobu , Miyakawa Kazuhisa , Müller‐Esterl Werner , Maeda Hiroshi
Published: November 2004

Bradykinin (BK) has multiple pathophysiologic functions such as induction of vascular permeability and mitogenesis, and it triggers the release of other mediators such as nitric oxide in inflammatory and cancer tissues. To explore the pathophysiologic roles of BK in tumor, we examined the distribution of BK B2 receptors in human adenocarcinoma (lung, stomach), lymphoma (lymph node), hepatoma, squamous cell carcinoma (lung) and carcinoid (duodenum), and in mouse colon adenocarcinoma 38 (C‐38) and sarcoma 180 (S‐180) tumor tissues. Immunohistochemical staining of tumor tissues with an anti‐BK B2 receptor antibody, or autoradiography with the B2 receptor antagonist [125I]HOE 140 (D‐Arg‐[Hyp Thi D‐Tic Oic8]‐BK) and the B2 receptor agonist [3H]BK indicated the presence of B2 receptors in all human tumor cells and murine S‐180 and C‐38 cells. Specific binding of [3H]HOE 140 was observed in S‐180 cells with a Kd of 2.1 nM. Binding of [125I]HOE 140 to S‐180 cells was competed by an excess amount (20–100 times) of nonradiolabeled HOE 140 or BK, but not by BK B1 receptor agonist des‐Arg9‐BK. These results provide direct evidence that the BK B2 receptor is expressed in human cancer and experimental murine tumors, which suggests a potential role for BK in inducing pathologic signal transduction in cancer growth and progression, nitric oxide production and vascular permeability enhancement in tumors. BK antagonists may thus have applications in the modulation of cancer growth and in paraneoplastic syndromes. © 2001 Wiley‐Liss, Inc.
Sun exposure and interaction with family history in risk of melanoma, Queensland, Australia
Authors: Siskind Victor , Aitken Joanne , Green Adèle , Martin Nicholas
Published: November 2004

Sun exposure is the main environmental risk factor for melanoma, but the timing of exposure during life that confers increased risk is controversial. Here we provide the first report of the association between lifetime and age‐specific cumulative ultraviolet exposure and cutaneous melanoma in Queensland, Australia, an area of high solar radiation, and examine the association separately for families at high, intermediate and low familial melanoma risk. Subjects were a population‐based sample of melanoma cases diagnosed and registered in Queensland between 1982 and 1990 and their relatives. The analysis included 1,263 cases and relatives with confirmed cutaneous melanoma and 3,111 first‐degree relatives without melanoma as controls. Data on lifetime residence and sun exposure, family history and other melanoma risk factors were collected by a mailed questionnaire. Using conditional multiple logistic regression with stratification by family, cumulative sun exposure in childhood and in adulthood after age 20 was significantly associated with melanoma, with estimated relative risks of 1.15 per 5,000 minimal erythemal doses (MEDs) from age 5 to 12 years, and 1.52 per 5 MEDs/day from age 20. There was no association with sun exposure in families at high familial melanoma risk. History of nonmelanoma skin cancer (relative risk [RR] = 1.26) and multiple sunburns (RR = 1.31) were significant risk factors. These findings indicate that sun exposure in childhood and in adulthood are important determinants of melanoma but not in those rare families with high melanoma susceptibility, in which genetic factors are likely to be more important. © 2002 Wiley‐Liss, Inc.
Cu/Zn superoxide dismutase plays a role in angiogenesis
Authors: Marikovsky Moshe , Nevo Nava , Vadai Ezra , Harris‐Cerruti Catherine
Published: November 2004

Endothelial cells produce oxygen radicals spontaneously and this process is augmented by hypoxia/reoxygenation. Cu/Zn superoxide dismutase (SOD‐1) is an important enzyme in cellular oxygen metabolism. To determine whether alterations in SOD‐1 activity affect angiogenesis we used transgenic SOD‐1 (Tg‐SOD) mice with elevated level of SOD‐1. Angiogenesis induced subcutaneously by bFGF in Tg‐SOD mice was 3‐fold higher than in control non‐transgenic (ntg) mice. Oral administration of disulfiram (DSF), an inhibitor of SOD‐1, inhibited angiogenesis in Tg‐SOD mice as well as in CD1 nude mice. Effects of DSF on cultured cells were also tested. Application of DSF to cultured bovine capillary endothelial (BCE) cells caused inhibition of DNA synthesis and induction of apoptosis. These effects were prevented by addition of antioxidants, further indicating involvement of reactive oxygen species. DSF also reduced the level of glutathione and the production of H2O2 in BCE cells. Moreover, PC12‐SOD cells with elevated SOD‐1 were less sensitive to DSF treatment then control cells. These data indicate that the effects of DSF are mediated by inhibition of SOD‐1 activity. Tumor development is known to largely depend on angiogenesis. We found that oral administration of DSF to mice caused significant inhibition of C6 glioma tumor development and marked reduction (by 10–19‐fold) in metastatic growth of Lewis lung carcinoma. The data suggest a role for SOD‐1 in angiogenesis, establish DSF as a potential inhibitor of angiogenesis and raise the possibility that attenuating SOD‐1 activity may be important in treatment of angiogenesis‐dependent pathologies. © 2002 Wiley‐Liss, Inc.
Changes in lung‐cancer mortality trends in Spain
Authors: Franco José , Pérez‐Hoyos Santiago , Plaza Pedro
Published: November 2004

Several changes in smoking patterns over the past decades in Spain can be expected to result in a shift in lung‐cancer mortality rates. We examined time trends in lung‐cancer mortality from 1973–1997 using a log‐linear Poisson age‐period‐cohort model. The standardized lung‐cancer mortality rate for men almost doubled, from 31.4 per 100,000 in 1973 to 58.6 in 1997, with an average annual increase of 2.7%. Mortality increased for male generations born until 1952 as a consequence of the increasing cigarette smoking in successive birth cohorts. However, the slight downward trend observed for the 2 youngest generations suggests a more favorable outcome of the lung‐cancer epidemic among Spanish males in the coming years, if this trend continues. For women, mortality rates were 5 to 9 times lower than those for men, 6.3 per 100,000 in 1973 and 6.4 in 1997. However, the increasing mortality among younger generations born since 1942 reflects the rise in the prevalence of smoking women during the last decades and can be expected to spread to older age groups as a cohort effect, indicating the early phase of the smoking‐related lung‐cancer epidemic among Spanish females. The decreasing mortality trend observed in women until the late 1980s could be attributed to a lower exposure to environmental tobacco smoke at home as a result of a significant reduction in the prevalence of smoking men. © 2002 Wiley‐Liss, Inc.
Expression of cancer/testis antigens in cutaneous T cell lymphomas
Authors: Häffner Andreas C. , Tassis Anatoli , Zepter Karoline , Storz Monique , Tureci Oezlem , Burg Günter , Nestle Frank Oliver
Published: November 2004

Cancer/testis‐antigens (CTA), a novel and expanding family of immunogenic proteins detected by serological screening of recombinant cDNA expression libraries, encompass promising candidate targets for T‐cell based immunotherapy. We screened kryo‐preserved tissue of cutaneous T cell lymphoma (CTCL, n=36) such as mycosis fungoides (MF, n=17), pleomorphic cutaneous T‐cell lymphoma (n=8) and Sezary's syndrome (SS, n= 11) as well as a non‐malignant entity (small plaques parapsoriasis, SPP, n=5), for the expression of CTA by RT‐PCR and Northern blot hybridization. From a panel of eleven CTA (MAGE‐1, MAGE‐C1, MAGE‐3, BAGE, GAGE, SSX‐1, SSX‐2, SSX4, SCP‐1, NY‐ESO‐1 and TS85) (HOM‐Tes‐85), mRNA expression could be detected for SCP‐1 in 8/17 MF and 6/8 pleomorphic CTCL patients but was completely absent in small plaques parapsoriasis. SS patients had a more heterogeneous antigen expression pattern: Gage (1/11), MAGE‐1 (3/11), MAGE‐3 (6/11), MAGE‐C1 (5/11), NY‐ESO‐1 (7/11) and TS85 (5/11), with expression of MAGE‐3 confirmed by immunohistochemistry. CTA could provide defined targets for antigen‐based vaccination in a high percentage of cases with CTCL. SCP‐1 might serve as an additional diagnostic indicator in early and clinically indistinct lesions suspicious for cutaneous T‐cell lymphoma. © 2001 Wiley‐Liss, Inc.
K‐ras mutation in helicobacter pylori‐associated chronic gastritis in patients with and without gastric cancer
Authors: Hiyama Toru , Haruma Ken , Kitadai Yasuhiko , Masuda Hiroshi , Miyamoto Masaki , Tanaka Shinji , Yoshihara Masaharu , Shimamoto Fumio , Chayama Kazuaki
Published: November 2004

Mutations of an oncogene, K‐ras, are associated with the development and progression of many types of human cancer. To elucidate the significance of K‐ras mutations in gastric carcinogenesis, we examined K‐ras mutations in gastric cancers and in Helicobacter pylori‐associated chronic gastritis (H. pylori‐CG), which is associated with an increased risk for the gastric cancer development. Specimens of gastric cancer and H. pylori‐CG were obtained from 64 gastric cancer patients with H. pylori‐CG, 99 cancer‐free H. pylori‐CG patients and 30 H. pylori‐negative healthy subjects. K‐ras mutations were examined by polymerase chain reaction‐single strand conformation polymorphism (PCR‐SSCP), followed by DNA sequencing analysis. K‐ras mutations were detected in 4 of 48 (8.3%) gastric cancers, in 10 of 163 (6.1%) H. pylori‐CG and none of the 30 H. pylori‐negative healthy subjects. In the gastric cancer patients, mutated K‐ras was detected in differentiated type cancers but not in any of the undifferentiated type cancers. K‐ras mutations in H. pylori‐CG were significantly more frequent in gastric cancer patients than in cancer‐free patients (10.9% vs. 3.0%, p = 0.044). In addition, K‐ras mutations in H. pylori‐CG were significantly more frequent in patients with K‐ras mutated gastric cancer than in patients with K‐ras unmutated gastric cancer (50.0% vs. 3.7%, p = 0.037). These data suggest that the genetic mechanism(s) of carcinogenesis differs between the differentiated type and the undifferentiated type of gastric cancer and that K‐ras mutations may be involved in the early stages of gastric carcinogenesis of the differentiated type. © 2001 Wiley‐Liss, Inc.
Changes in cell shape and anchorage in relation to the restriction point
Authors: Martinsson Hanna‐Stina , Zickert Peter , Starborg Maria , Larsson Olle , Zetterberg Anders
Published: November 2004

The restriction point (R) separates the G1 phase of continuously cycling cells into two functionally different parts. The first part, G1‐pm, represents the growth factor dependent post‐mitotic interval from mitosis to R, which is of constant length (3–4 h). The second part, G1‐ps, represents the growth factor independent, pre‐S phase interval of G1 that lasts from R to S and that varies in time from 1 to 10 h. G1‐pm cells rapidly exit (within 1 h) from the cell cycle and enter G0 as a response to serum withdrawal. The finding that R occurs at a set time after mitosis indicates that R may be related to the metabolic and/or structural changes that the cell underwent during the previous mitosis. We have recently shown that phosphorylation of the retinoblastoma tumor suppressor protein (pRb) is not the molecular mechanism behind R, as has been suggested previously. Here, we present an alternative explanation for R. In the present study, we applied a single cell approach using time‐lapse analysis, which revealed that upon serum starvation the G1‐pm cells rapidly underwent a transient change in cell shape from flat to spherical before exiting to G0. Platelet derived growth factor (PDGF) counteracted this change in shape and also prevented exit to G0 to the same extent. Furthermore epidermal growth factor (EGF) and insulin like growth factor (IGF‐1), which only partially counteracted this change, only partially counteracts exit to G0. These data clearly indicate a direct link between change in cell shape and exit to G0 in G1‐cells that have not passed R. © 2004 Wiley‐Liss, Inc.
Matricellular protein SPARC is translocated to the nuclei of immortalized murine lens epithelial cells
Authors: Yan Qi , Weaver Matt , Perdue Nikole , Sage E. Helene
Published: November 2004

The matricellular glycoprotein, secreted protein acidic and rich in cysteine (SPARC), has complex biological activities and is important for lens epithelial cell function and regulation of cataract formation. To understand how SPARC influences lens epithelial cell activity and homeostasis, we have studied the subcellular distribution of SPARC in murine lens epithelial cells in vitro. We demonstrate that endogenous SPARC is located in the cytoplasm of either quiescent or dividing lens epithelial cells in culture. However, cytoplasmic SPARC was translocated into the nuclei of immortalized lens epithelial cells upon a significant reduction of intracellular SPARC in these cells. Recombinant human (rh) SPARC added to the culture media was quickly and efficiently internalized into the cytosol of SPARC‐null lens epithelial cells. Moreover, cytoplasmic rhSPARC was also translocated into the nucleus after exogenous rhSPARC was removed from the culture media. The translocation of SPARC into the nucleus was therefore triggered by the reduction of SPARC protein normally available to the cells. A mouse SPARC–EGFP chimeric fusion protein (70 kDa) was expressed in lens epithelial cells and 293‐EBNA cells, and was observed both in the cytoplasm and culture medium, but not in the nucleus. SPARC does not appear to have a strong nuclear localization sequence. Alternatively, SPARC might pass through the nuclear pore complex by passive diffusion. SPARC therefore functions not only as an extracellular protein but also potentially as an intracellular protein to influence cellular activities and homeostasis. © 2004 Wiley‐Liss, Inc.
Different cation sensitivities and binding site domains of Na+–Ca2+–K+ and Na+–Ca2+ exchangers
Authors: Uehara Akira , Iwamoto Takahiro , Kita Satomi , Shioya Takao , Yasukochi Midori , Nakamura Yuki , Imanaga Issei
Published: November 2004

We examined inhibitory effects of external multivalent cations Ni2+, Co2+, Cd2+, La3+, Mg2+, and Mn2+ on reverse‐mode exchange of the K+‐dependent Na+/Ca2+ exchanger NCKX2 and the K+‐independent exchanger NCX1 expressed in CCL‐39 cells by measuring the rate of Ca2+ uptake with radioisotope tracer and electrophysiological techniques. The apparent affinities for block of Ca2+ uptake by multivalent cations was higher in NCKX2 than NCX1, and the rank order of inhibitory potencies among these cations was different. Additional experiments also showed that external Li+ stimulated reverse‐mode exchange by NCX1, but not NCKX2 in the presence of 5 mM K+. Thus, both exchangers exhibited differential sensitivities to not only K+ but also many other external cations. We attempted to locate the putative binding sites within the α motifs for multivalent cations by site‐directed mutagenesis experiments. The cation affinities of NCKX2 were altered by mutations of amino acid residues in the α‐1 motif, but not by mutations in the α‐2 motif. These results contrast with those for NCX1 where mutations in both α‐1 and α‐2 motifs have been shown previously to affect cation affinities. Susceptibility tests with sulfhydryl alkylating agents suggested that the α‐1 and α‐2 motifs are situated extracellularly and intracellularly, respectively, in both exchangers. A topological model is proposed in which the extracellular‐facing α‐1 motif forms an external cation binding site that includes key residues N203, G207C, and I209 in NCKX2, while both α‐1 and α‐2 motifs together form the binding sites in NCX1. © 2004 Wiley‐Liss, Inc.
Skeletal development of Macrochelys temminckii (Reptilia: Testudines: Chelydridae)
Authors: Sheil Christopher A.
Published: November 2004

Few descriptions of the development and sequence of chondrification and ossification of the entire skeleton of turtles exist, particularly compared to other groups of reptiles. In this study, the embryonic skeleton and its ontogenesis are described for the Alligator Snapping Turtle, Macrochelys temminckii (Chelydridae). Morphological descriptions utilize cleared and double‐stained embryonic specimens and form the basis of comparison of the ontogenesis of the skeleton between this species and its extant sister taxon, Chelydra serpentina. The embryonic chondrocranium, as well as the sequences of formation and ossification of the entire skeleton, are compared between these closely related species, and afford a unique opportunity to examine differences in their patterns of skeletal formation. In M. temminckii, the first elements to ossify (Stage 17) are associated with the dermatocranium and upper jaw, followed by elements of the palate, lower jaw, and long bones of the limbs. In both species the majority of endochondral braincase elements (prootic, opisthotic, supraoccipital, and exoccipital) ossify after the majority of dermal elements of the skull. The sequences of formation of the chondral primordia of the limb elements, as well as ossification of autopodial elements, are generally congruent between these species. J. Morphol. 263:71–106, 2005. © 2004 Wiley‐Liss, Inc.
Simultaneous detection of DNA synthesis, activation and cytokine secretion in collagen II (250–270)‐activated T lymphocytes by flow cytometry
Authors: Zhu Ping , Li Xueyi , Ding Jin , Fan Chunmei , Wang Yanhong , Wang Hongkun , Chen Zhinan
Published: November 2004

T cell activation and secretion of cytokines from activated peripheral blood mononuclear cells (PBMC) in culture have traditionally been measured by 3H‐thymidine incorporation for assessment of cell proliferation. However, this method has many disadvantages that limit its usage in analyzing antigen‐specific T responses, because of the low specific frequencies of the cells. Collagen II (250–270) may be an important autoantigen involved in the pathology of rheumatoid arthritis (RA). To further study the specific T cells response to CII 250–270, we developed an improved method for measuring lymphocyte proliferation and activation, and intracellular cytokine production, by flow cytometry at the single cell level. BrdU, an analog of thymidine, was incorporated into cellular DNA as a marker of individual cell proliferation. The cells were fixed and permeabilized, and a monoclonal antibody against BrdU conjugated with a fluorescent dye was used to measure BrdU incorporation. A Tris staining technique for the simultaneous determination of cell surface activation markers (CD69 or CD25) and intracellular cytokine production was also used and the parameters were assessed by 3‐color flow cytometry. Optimal conditions were selected to improve the sensitivity and specificity of the assays. This method allowed simultaneous detection of lymphocytic DNA synthesis, phenotype analysis and cytokine production at the single cell level, and thus it may be a useful tool for analyzing immune responses.
Comparing quality of care in non‐profit and for‐profit nursing homes: a process perspective
Authors: Chesteen Susan , Helgheim Berit , Randall Taylor , Wardell Don
Published: November 2004

Using data from a sample of nursing homes, this paper uses an operations centric approach to test the economic hypothesis asserting that quality in non‐profit healthcare entities will exceed quality in for‐profit counterparts [Arrow, K., 1963. Uncertainty and welfare economics of medical care. The American Economic Review, 5, 941–973]. For‐profit healthcare entities face an inherent conflict between providing profits to investors and health welfare to patients. Thus, non‐profit entities exist as a signal and evidence of higher quality services. To date, research examining differences in quality between for‐profit and non‐profit nursing homes has focused on a direct link between outcome quality and non‐profit status. These studies have produced inconclusive or mixed results. We argue that non‐profit or for‐profit status and outcome quality are linked via two intermediate factors, namely process quality and input quality. Consistent with many prior studies, we report no direct link between non‐profit status and outcome quality. However, we report that process quality is indeed higher at non‐profit nursing homes than for‐profit nursing homes, but that input quality is lower. We also examine the association between outcome quality with process and input quality. We report that different aspects of process quality are tied to better outcome quality, but report several notable exceptions. This research provides support for Arrow's hypothesis at the process level and gives insights into the link between process quality, input quality and outcome quality in the nursing home environment.
*-REPRESENTATION TYPE OF *-DOUBLES OF FINITE-DIMENSIONAL ALGEBRAS
Authors: Mazorchuk Volodymyr , Turowska Lyudmila
Published: November 2004

We determine when the $*$-double of a finite-dimensional complex algebra is $*$-finite, $*$-tame and $*$-wild.

AMS 2000 Mathematics subject classification: Primary 46K10; 16G60
Review Essay: Modernity and Religious Change in South Asian Islam
Authors: Zaman Muhammad Qasim
Published: November 2004

Over the course of the past several decades, Francis Robinson has done much to illuminate facets of the history and culture of the traditionally educated Muslim religious scholars, the ulama, of South Asia. “For far too long,” he writes, “[the] ulama have been treated as cardboard figures, caricatures of Muslim men of God…. [C]olonial administrators, and subsequently scholars, have rarely known enough to treat them as more than such; Western-educated Muslims, who have discovered new forms of authority, have often been concerned both to mock and to distance themselves from the mediators of religious authority; and the followers of ulama have been concerned to impose upon them an image of an ideal teacher and scholar at the cost of concealing aspects of their character, personality, and behaviour” (TheUlama of Farangi Mahall [hereafter FM], p. 148). The cost of letting the caricatures persist is high. In many instances, an understanding of the Muslim public sphere and of religious thought in modern Islam remains at best incomplete without serious attention to the ulama. And important facets of religious change likewise remain elusive unless the evolving discourses and the institutions of the ulama are brought within our purview. When more observers of Muslim societies come to recognise the ways in which the ulama are integral to the history of modern and not just of medieval Islam, it would be in some measure due to the influence of Robinson's writings. Among other things, Robinson's work is significant for its insistence that we consider how religious ideas, norms, and traditions shape politics instead of treating them as little more than symbols employed by the political elite for purposes of mass political mobilisation. At the same time, he has explored how religious identities and institutions have themselves evolved in the nineteenth and the twentieth centuries. And with the history and culture of the ulama as his primary point of reference, he has brought to light new perspectives on Islam in South Asia, as well as on the historical interaction between South Asia and the Muslim world at large.
Royal Asiatic Society Honorary Treasurer's Report to the 2004 AGM
Authors: Naylor C. C. F.
Published: November 2004

The Council's report and the accounts, which you have before you, cover a year in which the charitable activities of the Society continued in a manner broadly comparable with the past. As usual I am going to draw your attention to certain significant financial aspects and not go through all the detail.
ALADYN: A method to investigate auroral arc electrodynamics from satellite data
Authors: Marghitu O. , Klecker B. , Haerendel G. , McFadden J.
Published: November 2004

In the simplest representation of an auroral arc current system, the arc consists of a homogeneous block of increased conductance infinitely extended in longitudinal direction; field‐aligned current (FAC) sheets that flow in and out of the ionosphere at the boundaries of the arc are connected through Pedersen current across the arc, while the electrojet (EJ) that flows along the arc as Hall current is divergence‐free. To evaluate the deviation of the real arc current system from this ideal configuration, we developed the ALADYN (Auroral Arc Electrodynamics) method, based on a parametric model of the arc, that allows the derivation of the parameters by numerical fit to the experimental data. The method is illustrated with a wide, stable, winter evening arc, for which both Fast Auroral Snapshot (FAST) Explorer measurements at 3850 km altitude and ground optical data are available. We find that in order to obtain consistent results, one has to take into account, as a minimum, the ionospheric polarization, the contribution of the Hall current to the meridional closure of the FAC, and the coupling between the FAC and the EJ.
Magnetic fluctuations and Hall magnetohydrodynamic turbulence in the solar wind
Authors: Krishan V. , Mahajan S. M.
Published: November 2004

It is shown that the framework of Hall magnetohydrodynamics (Hall‐MHD), which can support three quadratic invariants and allows nonlinear states to depart fundamentally from the Alfvénic, is capable of reproducing in the inertial range the three branches of the observed solar wind magnetic fluctuation spectrum: the Kolmogorov branch f−5/3, steepening to with α1 ≃ 3–4 on the high‐frequency side and flattening to f−1 on the low‐frequency side. These fluctuations are found to be associated with the nonlinear Hall‐MHD shear Alfvén waves. The spectrum of the concomitant whistler‐type fluctuations is very different from the observed one. Perhaps the relatively stronger damping of the whistler fluctuations may cause their unobservability. The issue of the anisotropy of the turbulence is addressed briefly.
The intestinal anti‐inflammatory effect of quercitrin is associated with an inhibition in iNOS expression
Authors: Camuesco Desiree , Comalada Monica , Rodríguez‐Cabezas M Elena , Nieto Ana , Lorente Maria D , Concha Angel , Zarzuelo Antonio , Gálvez Julio
Published: November 2004

Quercitrin, 3‐rhamnosylquercetin, is a bioflavonoid with antioxidant properties, which exerts anti‐inflammatory activity in experimental colitis. In the present study, different in vivo experiments were performed in order to evaluate the mechanisms of action involved in this effect, with special attention to its effects on proinflammatory mediators, including nitric oxide (NO).

Experimental colitis was induced in female Wistar rats by incorporation of dextran sodium sulfate (DSS) in drinking water. Oral treatment of quercitrin (1 or 5 mg kg−1 day−1) to colitic rats ameliorated the evolution of the inflammatory process induced when administered in a preventative dosing protocol. When quercitrin (1 mg kg−1 day−1) was administered on established colitis, it facilitated the recovery of the inflamed mucosa.

The beneficial effects exerted by quercitrin were evidenced both histologically and biochemically, and were associated with an improvement in the colonic oxidative status, altered as a consequence of the colonic insult induced by DSS. In addition, a reduction of colonic NO synthase activity was observed, probably related to a decreased expression in the inducible form of the enzyme via downregulation in the colonic activity of the nuclear factor‐κB.

Immunohistochemical studies showed that quercitrin treatment reduced macrophage and granulocyte infiltration in the inflamed tissue.

British Journal of Pharmacology (2004) 143, 908–918. doi:10.1038/sj.bjp.0705941
Modulation of voltage‐gated channel currents by harmaline and harmane
Authors: Splettstoesser Frank , Bonnet Udo , Wiemann Martin , Bingmann Dieter , Büsselberg Dietrich
Published: November 2004

Harmala alkaloids are endogenous substances, which are involved in neurodegenerative disorders such as M. Parkinson, but some of them also have neuroprotective effects in the nervous system.

While several sites of action at the cellular level (e.g. benzodiazepine receptors, 5‐HT and GABAA receptors) have been identified, there is no report on how harmala alkaloids interact with voltage‐gated membrane channels.

The aim of this study was to investigate the effects of harmaline and harmane on voltage‐activated calcium‐ (ICa(V)), sodium‐ (INa(V)) and potassium (IK(V))‐channel currents, using the whole‐cell patch‐clamp method with cultured dorsal root ganglion neurones of 3‐week‐old rats. Currents were elicited by voltage steps from the holding potential to different command potentials.

Harmaline and harmane reduced ICa(V), INa(V) and IK(V) concentration‐dependent (10–500 μM) over the voltage range tested. ICa(V) was reduced with an IC50 of 100.6 μM for harmaline and by a significantly lower concentration of 75.8 μM (P<0.001, t‐test) for harmane. The Hill coefficient was close to 1. Threshold concentration was around 10 μM for both substances.

The steady state of inhibition of ICa(V) by harmaline or harmane was reached within several minutes. The action was not use dependent and at least partly reversible.

It was mainly due to a reduction in the sustained calcium channel current (ICa(L+N)), while the transient voltage‐gated calcium channel current (ICa(T)) was only partially affected.

We conclude that harmaline and harmane are modulators of ICa(V) in vitro. This might be related to their neuroprotective effects.

British Journal of Pharmacology (2005) 144, 52–58. doi:10.1038/sj.bjp.0706024
Structure, conformation and biological activity of a novel lipodepsipeptide from Pseudomonas corrugata: cormycin A
Authors: SCALONI Andrea , DALLA SERRA Mauro , AMODEO Pietro , MANNINA Luisa , VITALE Rosa Maria , SEGRE Anna Laura , CRUCIANI Oscar , LODOVICHETTI Francesca , GRECO Maria Luigia , FIORE Alberto , GALLO Monica , D'AMBROSIO Chiara , CORAIOLA Manuela , MENESTRINA Gianfranco , GRANITI Antonio , FOGLIANO Vincenzo
Published: November 2004

Cationic lipodepsipeptides from Pseudomonas spp. have been characterized for their structural and antimicrobial properties. In the present study, the structure of a novel lipodepsipeptide, cormycin A, produced in culture by the tomato pathogen Pseudomonas corrugata was elucidated by combined protein chemistry, mass spectrometry and two-dimensional NMR procedures. Its peptide moiety corresponds to L-Ser-D-Orn-L-Asn-D-Hse-L-His-L-aThr-Z-Dhb-L-Asp(3-OH)-L-Thr(4-Cl) [where Orn represents ornithine, Hse is homoserine, aThr is allo-threonine, Z-Dhb is 2,3-dehydro-2-aminobutanoic acid, Asp(3-OH) is 3-hydroxyaspartic acid and Thr(4-Cl) is 4-chlorothreonine], with the terminal carboxy group closing a macrocyclic ring with the hydroxy group of the N-terminal serine residue. This is, in turn, N-acylated by 3,4-dihydroxy-esadecanoate. In aqueous solution, cormycin A showed a rather compact structure, being derived from an inward orientation of some amino acid side chains and from the ‘hairpin-bent’ conformation of the lipid, due to inter-residue interactions involving its terminal part. Cormycin was significantly more active than the other lipodepsipeptides from Pseudomonas spp., as demonstrated by phytotoxicity and antibiosis assays, as well as by red-blood-cell lysis. Differences in biological activity were putatively ascribed to its weak positive net charge at neutral pH. Planar lipid membrane experiments showed step-like current transitions, suggesting that cormycin is able to form pores. This ability was strongly influenced by the phospholipid composition of the membrane and, in particular, by the presence of sterols. All of these findings suggest that cormycin derivatives could find promising applications, either as antifungal compounds for topical use or as post-harvest biocontrol agents.
Mutational analysis of histidine residues in human organic anion transporter 4 (hOAT4)
Authors: ZHOU Fanfan , PAN Zui , MA Jianjie , YOU Guofeng
Published: November 2004

Human organic anion transporter 4 (hOAT4) belongs to a family of organic anion transporters which play critical roles in the body disposition of clinically important drugs, including anti-HIV therapeutics, antitumour drugs, antibiotics, anti-hypertensives and anti-inflammatories. hOAT4-mediated transport of the organic anion oestrone sulphate in COS-7 cells was inhibited by the histidine-modifying reagent DEPC (diethyl pyrocarbonate). Therefore the role of histidine residues in the function of hOAT4 was examined by site-directed mutagenesis. All five histidine residues of hOAT4 were converted into alanine, singly or in combination. Single replacement of His-47, or simultaneous replacement of His-47/52/83 or His-47/52/83/305/469 (H-less) led to a 50–80% decrease in transport activity. The decreased transport activity of these mutants was correlated with a decreased amount of cell-surface expression, although the total cell expression of these mutants was similar to that of wild-type hOAT4. These results suggest that mutation at positions 47, 47/52/83 and 47/52/83/305/469 impaired membrane expression rather than function. We also showed that, although most of the histidine mutants of hOAT4 were sensitive to inhibition by DEPC, H469A (His-469→Ala) was completely insensitive to inhibition by this reagent. Therefore modification of His-469 is responsible for the inhibition of hOAT4 by DEPC.
NMR characterization of the interaction between the C-terminal domain of interferon-γ and heparin-derived oligosaccharides
Authors: VANHAVERBEKE Cécile , SIMORRE Jean-Pierre , SADIR Rabia , GANS Pierre , LORTAT-JACOB Hugues
Published: November 2004

Interferons are cytokines that play a complex role in the resistance of mammalian hosts to pathogens. IFNγ (interferon-γ) is secreted by activated T-cells and natural killer cells. IFNγ is involved in a wide range of physiological processes, including antiviral activity, immune response, cell proliferation and apoptosis, as well as the stimulation and repression of a variety of genes. IFNγ activity is modulated by the binding of its C-terminal domain to HS (heparan sulphate), a glycosaminoglycan found in the extracellular matrix and at the cell surface. In the present study, we analysed the interaction of isolated heparin-derived oligosaccharides with the C-terminal peptide of IFNγ by NMR, in aqueous solution. We observed marked changes in the chemical shifts of both peptide and oligosaccharide compared with the free state. Our results provide evidence of a binding through electrostatic interactions between the charged side chains of the protein and the sulphate groups of heparin that does not induce specific conformation of the C-terminal part of IFNγ. Our data also indicate that an oligosaccharide size of at least eight residues displays the most efficient binding.
A novel member of the GCN5-related N-acetyltransferase superfamily from Caenorhabditis elegans preferentially catalyses the N-acetylation of thialysine [S-(2-aminoethyl)-L-cysteine]
Authors: ABO-DALO Benjamin , NDJONKA Dieudonne , PINNEN Francesco , LIEBAU Eva , LÜERSEN Kai
Published: November 2004

The putative diamine N-acetyltransferase D2023.4 has been cloned from the model nematode Caenorhabditis elegans. The 483 bp open reading frame of the cDNA encodes a deduced polypeptide of 18.6 kDa. Accordingly, the recombinantly expressed His6-tagged protein forms an enzymically active homodimer with a molecular mass of approx. 44000 Da. The protein belongs to the GNAT (GCN5-related N-acetyltransferase) superfamily, and its amino acid sequence exhibits considerable similarity to mammalian spermidine/spermine-N1-acetyltransferases. However, neither the polyamines spermidine and spermine nor the diamines putrescine and cadaverine were efficiently acetylated by the protein. The smaller diamines diaminopropane and ethylenediamine, as well as L-lysine, represent better substrates, but, surprisingly, the enzyme most efficiently catalyses the N-acetylation of amino acids analogous with L-lysine. As determined by the kcat/Km values, the C. elegans N-acetyltransferase prefers thialysine [S-(2-aminoethyl)-L-cysteine], followed by O-(2-aminoethyl)-L-serine and S-(2-aminoethyl)-D,L-homocysteine. Reversed-phase HPLC and mass spectrometric analyses revealed that N-acetylation of L-lysine and L-thialysine occurs exclusively at the amino moiety of the side chain. Remarkably, heterologous expression of C. elegans N-acetyltransferase D2023.4 in Escherichia coli, which does not possess a homologous gene, results in a pronounced resistance against the anti-metabolite thialysine. Furthermore, C. elegans N-acetyltransferase D2023.4 exhibits the highest homology with a number of GNATs found in numerous genomes from bacteria to mammals that have not been biochemically characterized so far, suggesting a novel group of GNAT enzymes closely related to spermidine/spermine-N1-acetyltransferase, but with a distinct substrate specificity. Taken together, we propose to name the enzyme ‘thialysine Nε-acetyltransferase’.
Spermidine/spermine-N1-acetyltransferase-2 (SSAT2) acetylates thialysine and is not involved in polyamine metabolism
Authors: COLEMAN Catherine S. , STANLEY Bruce A. , JONES A. Daniel , PEGG Anthony E.
Published: November 2004

Spermidine/spermine-N1-acetyltransferase (SSAT1) is a short-lived polyamine catabolic enzyme inducible by polyamines and polyamine analogues. Induction of SSAT1 plays an important role in polyamine homoeostasis, since the N1-acetylated polyamines can be excreted or oxidized by acetylpolyamine oxidase. We have purified a recombinant human acetyltransferase (SSAT2) that shares 45% identity and 61% homology with human SSAT1, but is only distally related to other known members of the GNAT (GCN5-related N-acetyltransferase) family. Like SSAT1, SSAT2 is widely expressed, but did not turn over rapidly, and levels were unaffected by treatments with polyamine analogues. Despite similarity in sequence to SSAT1, polyamines were found to be poor substrates of purified SSAT2, having Km values in the low millimolar range and kcat values of <0.01 s−1. The kcat/Km values for spermine and spermidine for SSAT2 were <0.0003% those of SSAT1. Expression of SSAT2 in NIH-3T3 cells was not detrimental to growth, and did not reduce polyamine content or increase acetylpolyamines. These results indicate that SSAT2 is not a polyamine catabolic enzyme, and that polyamines are unlikely to be its natural intracellular substrates. A promising candidate for the physiological substrate of SSAT2 is thialysine [S-(2-aminoethyl)-L-cysteine], which is acetylated predominantly at the ε-amino group with Km and kcat values of 290 μM and 5.2 s−1. Thialysine is a naturally occurring modified amino acid that can undergo metabolism to form cyclic ketimine derivatives found in the brain and as urinary metabolites, which can undergo further reaction to form antioxidants. SSAT2 should be renamed ‘thialysine Nε-acetyltransferase’, and may regulate this pathway.
A crustacean Ca2+-binding protein with a glutamate-rich sequence promotes CaCO3 crystallization
Authors: ENDO Hirotoshi , TAKAGI Yasuaki , OZAKI Noriaki , KOGURE Toshihiro , WATANABE Toshiki
Published: November 2004

The DD4 mRNA of the penaeid prawn Penaeus japonicus was shown previously to be expressed in the epidermis adjacent to the exoskeleton specifically during the post-moult period, when calcification of the exoskeleton took place. The encoded protein possessed a Ca2+-binding site, suggesting its involvement in the calcification of the exoskeleton. In the present study, an additional ORF (open reading frame) of 289 amino acids was identified at the 5′ end of the previous ORF. The newly identified part of the encoded protein included a region of approx. 120 amino acids that was highly rich in glutamate residues, and contained one or more Ca2+-binding sites. In an immunohistochemical study, signals were detected within calcified regions in the endocuticular layer of the exoskeleton. Bacterially expressed partial segments of the protein induced CaCO3 crystallization in vitro. Finally, a reverse transcription-PCR study showed that the expression was limited to an early part of the post-moult period, preceding significant calcification of the exoskeleton. These observations argue for the possibility that the encoded protein, renamed crustocalcin (CCN), promotes formation of CaCO3 crystals in the exoskeleton by inducing nucleation.
The application of sediment capping agents on phosphorus speciation and mobility in a sub-tropical dunal lake
Authors: Akhurst Darren , Jones Graham B. , McConchie David M.
Published: November 2004

Experimental sediment cores from Lake Ainsworth, Australia, were exposed to an induced 46-day, anoxic/oxic cycle in the laboratory, mimicking the seasonal thermal stratification cycle commonly observed in the lake’s waters every summer. Under oxic conditions the supply of phosphorus (P) and iron (Fe) to the overlying water was slow, however, induced anoxia led to an enhanced release of P and Fe from the sediments to the water column. An inverse relationship between total P, Fe and redox potential suggests that Lake Ainsworth sediments are redox sensitive. Phosphorus speciation analysis of Lake Ainsworth sediments revealed the presence of a large pool of organic P, reactive Fe-bound P, and CaCO3-bound P, the latter fraction decreasing during anoxic conditions. Two sediment-capping agents, a lanthanum modified bentonite clay and Bauxsol (a waste product from the aluminium smelting industry) were assessed for their ability to reduce the levels of P released from Lake Ainsworth sediments during the 46-day, anoxic/oxic cycle. The bentonite clay was highly effective at reducing plant available P in anoxic/oxic conditions, but levels of dissolved Fe were enhanced with its use. Although the use of Bauxsol to remove plant available P is not recommended in anoxic waters, its use in suspension in oxic waters warrants further study.
Electron transfer between hemes in mammalian cytochrome
c
oxidase
Authors: Pilet Eric , Jasaitis Audrius , Liebl Ursula , Vos Marten H.
Published: November 2004

Fast intraprotein electron transfer reactions associated with enzymatic catalysis are often difficult to synchronize and therefore to monitor directly in non-light-driven systems. However, in the mitochondrial respiratory enzyme cytochrome oxidase
aa
3
, the kinetics of the final electron transfer step into the active site can be determined: reverse electron flow between the close-lying and chemically identical hemes
a
3
and
a
can be initiated by flash photolysis of CO from reduced heme
a
3
under conditions where heme
a
is initially oxidized. To follow this reaction, we used transient absorption spectroscopy, with femtosecond time resolution and a time window extending to 4 ns. Comparison of the picosecond heme
a
3
-CO photodissociation spectra under different redox states of heme
a
shows significant spectral interaction between both hemes, a phenomenon complicating the interpretation of spectral studies with low time resolution. Most importantly, we show that the intrinsic electron equilibration, corresponding to a ΔG
0
of 45-55 meV, occurs in 1.2 ± 0.1 ns. This is 3 orders of magnitude faster than the previously established equilibration phase of ≈3 μs, which we suggest to reflect a change in redox equilibrium closely following CO migration out of the active site. Our results allow testing a number of conflicting predictions regarding this reaction between both experimental and theoretical studies. We discuss the potential physiological relevance of fast equilibration associated with this low-driving-force redox reaction.
A versatile statistical analysis algorithm to detect genome copy number variation
Authors: Daruwala Raoul-Sam , Rudra Archisman , Ostrer Harry , Lucito Robert , Wigler Michael , Mishra Bud
Published: November 2004

We have developed a versatile statistical analysis algorithm for the detection of genomic aberrations in human cancer cell lines. The algorithm analyzes genomic data obtained from a variety of array technologies, such as oligonucleotide array, bacterial artificial chromosome array, or array-based comparative genomic hybridization, that operate by hybridizing with genomic material obtained from cancer and normal cells and allow detection of regions of the genome with altered copy number. The number of probes (i.e., resolution), the amount of uncharacterized noise per probe, and the severity of chromosomal aberrations per chromosomal region may vary with the underlying technology, biological sample, and sample preparation. Constrained by these uncertainties, our algorithm aims at robustness by using a priorless maximuma posterioriestimator and at efficiency by a dynamic programming implementation. We illustrate these characteristics of our algorithm by applying it to data obtained from representational oligonucleotide microarray analysis and array-based comparative genomic hybridization technology as well as to synthetic data obtained from an artificial model whose properties can be varied computationally. The algorithm can combine data from multiple sources and thus facilitate the discovery of genes and markers important in cancer, as well as the discovery of loci important in inherited genetic disease.