bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation of graft copolymers from deproteinized and high ammonia concentrated natural rubber latices with methyl methacrylate
Authors: Nakason C. , Kaesaman A. , Yimwan N.
Published: November 2002

Deproteinized natural rubber (DPNR) latex was prepared by the incubation of fresh natural latex with a proteolytic enzyme. The DPNR latex was later used to prepare a graft copolymer with methyl methacrylate (MMA). High ammonia (HA) concentrated latex was also used to prepare a graft copolymer with MMA. The appropriate reaction time was 3 h at a reaction temperature of 50°C. The conversion percentage of the graft reaction with DPNR was higher than that of the system with HA. The grafting efficiency percentage decreased with an increasing concentration of MMA in the graft reaction. In a comparison of the two types of latices, it was found that the reaction with DPNR provided higher grafting efficiency. Furthermore, a larger quantity of grafted poly(methyl methacrylate), a larger average particle size, and fewer free natural rubber molecules were also observed in the grafting system with DPNR. The difference between the reactions of the DPNR and HA latices was attributed to the removal of proteins, which acted as free‐radical scavengers. They terminated the free‐radical species during the graft copolymerization. © 2002 Wiley Periodicals, Inc. J Appl Polm Sci 87:68–75, 2003
Linkage and interaction of loci on 1q23 and 16q12 may contribute to susceptibility to systemic lupus erythematosus
Authors: Tsao Betty P. , Cantor Rita M. , Grossman Jennifer M. , Kim Sung K. , Strong Noel , Lau Chak S. , Chen Chung‐Jen , Shen Nan , Ginzler Ellen M. , Goldstein Rose , Kalunian Kenneth C. , Arnett Frank C. , Wallace Daniel J. , Hahn Bevra H.
Published: November 2002

Objective

Six recent genome scans of different systemic lupus erythematosus (SLE) multiplex family cohorts showed multiple putative susceptibility loci. In the present study, we examined 4 previously identified loci to replicate findings of significant linkage to 1q23 and 16q12, and to support findings of suggestive linkage to 14q21‐23 and 20p12 in a cohort of 115 multiethnic nuclear families containing 145 SLE‐affected sibpairs.

Methods

Model‐free, multipoint linkage analyses (SIBPAL2, SAGE version 4.0) and exclusion mapping (GeneHunter) were performed.

Results

Linkages to 1q23 (peak at D1S2675, mean allele sharing [MAS] 0.56; P = 0.003) and to 16q12 (peaks between D16S753 and D16S757, MAS 0.57; P = 0.003) were confirmed, but linkage evidence at 20p12 was weak and inconsistent (MAS 0.52–0.56; from P = 0.005 to P not significant). Evidence for linkage to 1q23 and 16q12 was stronger in 68 non‐Caucasian affected sibpairs than in 77 Caucasian affected sibpairs. Exclusion mapping ruled out linkage at 14q21‐23 (λs [sib recurrence risk or genotypic risk ratio] = 1.8). Because the pericentromeric region of chromosome 16 has been identified by genome scans in several autoimmune diseases, we postulated that it might harbor an autoimmune modifier gene. To explore this possibility, we tested for an interaction between 16q12 and 1q23, and between 16q12 and 20p12. Haplotype sharing at 1q23 increased concomitantly with increased haplotype sharing at 16q12 (P = 0.008 by nonparametric Jonckheere‐Terpstra exact statistical test). No evidence supporting an interaction between 16q12 and 20p12 was observed. Analysis of sibpairs sharing 2 alleles at 16q12 also showed increased allele sharing at 1q23 (MAS from 0.56 to 0.65).

Conclusion

These data support the presence of SLE susceptibility genes at 1q23 and 16q12, particularly in non‐Caucasians. The skewed distribution of haplotypes suggests that genetic interaction of these two loci may affect SLE susceptibility.
Association of novel polymorphisms with the expression of SPARC in normal fibroblasts and with susceptibility to scleroderma
Authors: Zhou Xiaodong , Tan Filemon K. , Reveille John D. , Wallis Debra , Milewicz Dianna M. , Ahn Chul , Wang Andrew , Arnett Frank C.
Published: November 2002

Objective

Fibroblasts from patients with systemic sclerosis (SSc) have an activated phenotype characterized by increased synthesis of extracellular matrix (ECM) components. SPARC (secreted protein, acidic and rich in cysteine) regulates the deposition or assembly of ECM components. The aim of this study was to investigate the role of SPARC in SSc susceptibility by functional and genetic association studies.

Methods

Complementary DNA (cDNA) microarrays were used to obtain gene expression data on cultured dermal fibroblasts from SSc patients. SPARC protein levels were assessed by Western blotting. Five polymorphic microsatellite markers within 5 cM of the SPARC gene (chromosome 5q31‐32) were genotyped in Choctaw Indians, a population previously shown to have a high prevalence of SSc. Discovery of single‐nucleotide polymorphisms (SNPs) was accomplished by sequencing the SPARC cDNA. These SNPs were then genotyped in a multi‐ethnic cohort of SSc patients to determine potential associations with disease susceptibility in a broader population of SSc patients, as well as with various clinical and immunologic features of SSc. The functional relevance of these SNPs with regard to transcript stability of SPARC was also assessed.

Results

Microarrays demonstrated increased expression of SPARC, along with other ECM genes, in SSc patients compared with normal controls. SSc fibroblasts also had increased SPARC protein levels. Three of 5 microsatellite markers near SPARC showed significant associations with SSc in the Choctaw SSc patients. Sequencing of SPARC cDNA revealed 3 novel SNPs in the 3′‐untranslated region at +998 (C→G), +1551 (C→G), and +1922 (T→G). Homozygosity for the C allele at SNP +998 was significantly increased in SSc patients across ethnic lines. SPARC SNPs +1551 and +1922 demonstrated correlations with Raynaud's phenomenon and pulmonary fibrosis, respectively. Functional studies of SPARC SNP +998 in normal fibroblast cultures suggested a correlation between the SNP +998 C allele polymorphism and an increased messenger RNA half‐life.

Conclusion

This study is the first to show that polymorphisms of the SPARC gene are associated with susceptibility to, and clinical manifestations of, SSc and that they may also be functionally important in influencing SPARC expression in skin fibroblasts.
Matrix homeostasis in aging normal human ankle cartilage
Authors: Aurich Matthias , Poole A. Robin , Reiner Agnes , Mollenhauer Christine , Margulis Arkady , Kuettner Klaus E. , Cole Ada A.
Published: November 2002

Objective

To study age‐related (as opposed to arthritis‐related) changes in collagen and proteoglycan turnover.

Methods

Macroscopically nondegenerate normal ankle cartilage obtained from 30 donors (ages 16–75 years) was processed for in situ hybridization to detect messenger RNA (mRNA) of type IIB collagen (CIIB); antibodies to the C‐propeptide of type II collagen (CPII), to the type II collagen (CII) collagenase‐generated cleavage neoepitope (Col2‐3/4Cshort), and to the CII denaturation product (Col2‐3/4m) were used for immunohistochemistry analysis and immunoassay. In addition, immunoblotting was used to detect the 4 collagenases. Assays were also performed to detect glycosaminoglycan (GAG) content and the 846 epitope of aggrecan.

Results

There were no significant changes in CII, GAG, and the content of the 846 epitope after the age of 30 years. Both mRNA for CIIB and the CPII were present in all zones, and CPII content did not change significantly with age. While the collagenase‐cleaved CII showed a trend to increase with age, the denatured collagen did not. However, the molar ratio of cleaved versus denatured collagen was positively correlated with age. All 4 collagenases were detectable in the ankle cartilage but showed no identifiable changes in content with age.

Conclusion

Synthesis and degradation of CII is associated with the pericellular matrix and is maintained at a steady state throughout life. The contents of CII and proteoglycan did not change. There was a significant reduction in the denaturation of CII with age, relative to collagenase‐mediated cleavage. These observations reveal that, in aging of the intact ankle articular cartilage, there is no evidence of molecular degenerative changes of the kind observed in osteoarthritis, thereby distinguishing aging from the osteoarthritis process.
Regional planning implementation and its impact on integration of a mental health care network
Authors: Fleury Marie Josée , Mercier Céline , Denis Jean‐Louis
Published: November 2002

This article questions the effectiveness of a managerial tool in changing a health‐care system. The process of implementing regional planning and its impact on creating integrated service networks is examined, using a case study and a multi‐dimensional analytic model. This model highlights the influence of contextual, structural, cultural and dynamic factors on forming networks. The regional planning developed in the province of Québec (Canada), aimed at a major transformation of the mental health‐care system. In each district, organizations working with people who have serious mental disorders were mobilized to plan and implement a more coordinated, continuous and diversified supply of services, under the direction of a regional health body. This study outlines the limitations of regional planning as a tactic for transforming the system. It recommends instead developing more diversified integration strategies to further the process of forming integrated service networks within a complex system. In conclusion, a brief discussion deals with the difficulties related to the study of systemic change implementation. Copyright © 2002 John Wiley & Sons, Ltd.
NMR diffusion coefficient study of steroid–cyclodextrin inclusion complexes
Authors: Cameron Kenneth S. , Fielding Lee
Published: November 2002

The complexes formed by the steroid rocuronium bromide with four different cyclodextrins (β‐cyclodextrin, γ‐cyclodextrin, Org 26054 and Org 25969) were investigated. The diffusion coefficients of the steroid–cyclodextrin complexes were 6–15% lower than those of the native cyclodextrins, consistent with a 1 : 1 stoichiometry for all of the complexes. Copyright © 2002 John Wiley & Sons, Ltd.
Pulsed field gradient NMR investigation of solubilization equilibria in amino acid and dipeptide terminated micellar and polymeric surfactant solutions
Authors: Hickok Robin S. , Wedge Seamus A. , Hansen Alexandar L. , Morris Kevin F. , Billiot Fereshteh Haddadian , Warner Isiah M.
Published: November 2002

Pulsed field gradient NMR spectroscopy was used to investigate the association of toluene, chlorobenzene and benzyl alcohol with amino acid and dipeptide terminated polymerized surfactants (PS). The diffusion coefficient for each probe was measured in the presence and absence of the polymers and the mole fraction of bound probe molecules, fb, was calculated. For all solutions investigated, the probes associated more strongly with unpolymerized surfactant micelles than with corresponding PS. For example, the toluene fb values for association with sodium undecanoyl valinate micelles and the PS poly(sodium undecanoyl valinate) were 0.88 and 0.15, respectively. The relatively weak probe–polymer association was attributed to the polarity and fluidity of the polymers' hydrocarbon cores and to the fact that these PS have smaller aggregation numbers than the corresponding unpolymerized surfactant micelles. Copyright © 2002 John Wiley & Sons, Ltd.
A one‐shot sequence for high‐resolution diffusion‐ordered spectroscopy
Authors: Pelta Michelle D. , Morris Gareth A. , Stchedroff Marc J. , Hammond Stephen J.
Published: November 2002

Diffusion‐ordered spectroscopy (DOSY) is a powerful method for the NMR analysis of mixtures such as crude synthetic products, biofluids or biological extracts. Mixtures can be analysed without the need for any physical separation, and the method requires only standard NMR pulsed field gradient hardware. Existing pulse sequences for DOSY require extensive and time‐consuming phase cycling for clean results. A new sequence is reported here which allows clean spectra with good lineshapes to be obtained using as little as one transient per gradient value. Asymmetric bipolar field gradient pulse pairs are used in conjunction with extra balancing gradient pulses, selecting a unique coherence transfer pathway but minimizing eddy current effects and field‐frequency lock disturbance. Using the new sequence, high‐resolution proton DOSY spectra can be obtained in less than 1 min. Copyright © 2002 John Wiley & Sons, Ltd.
Typical masonry failures and repairs: a German Engineer's view
Authors: Dialer Christian P
Published: November 2002

Masonry is one of the oldest or maybe the oldest building material of all. Starting with a very short historical review, the paper gives some remarks on the basic mechanical and material behaviour of the discontinuous, nonlinear behaviour of masonry as a jointed block structure. It is important to keep in mind that there is a big difference in masonry on different sides of the Atlantic.

Basic principles and statements dealing with the compressive (uniaxial, biaxial) and shear strength are derived. Typical failures and repairs are discussed. Taking into account the complex structure and the large variety with respect to block sizes, block qualities, mortars, bond forces and the overall geometry, the designer is forced to use alternative modelling techniques to the finite element method (FEM).

One alternative is the distinct element method (DEM), which allows large rotations of the blocks and large deformations, e.g. separations in and of the joints. This method is well established for analysing rock masses, but, as is demonstrated in this paper, it is also well suited to investigate masonry failure mechanisms. The discontinuous non‐homogeneous behaviour of masonry can be modelled very well, and the results can be favourably compared with real cracking behaviour.
Revisiting the dividend puzzle
Authors: Baker H.Kent , Powell Gary E. , Veit E.Theodore
Published: November 2002

This paper revisits the dividend puzzle, described here as questions about the relevance of dividend policy and how managers should (and do) determine dividend policy. We examine theoretical and empirical research on dividends and share repurchases because they are the principal mechanisms by which corporations disburse cash to their shareholders. Despite a voluminous amount of study, researchers still do not have all the answers to the dividend puzzle. However, we are closer to its resolution. We also do not have definitive answers to why managers choose one method of cash distribution over the other. Solving the dividend puzzle may depend on understanding the effects of various market imperfections or frictions. Because various imperfections affect firms differently, dividend policy may vary substantially from one firm to another. Models that consider the competing frictions on a firm‐specific basis offer promise for resolving the dividend puzzle.
Shallow viscoplastic flow on an inclined plane
Authors: BALMFORTH N. J. , CRASTER R. V. , SASSI R.
Published: November 2002

Evolving viscoplastic flows upon slopes are an important idealization of many flows
in a variety of geophysical situations where yield stress is thought to play a role. For
such models, asymptotic expansions suitable for slowly moving shallow fluid layers
(lubrication theory) reduce the governing equations to a simpler problem in terms of
the fluid thickness. We consider the version of the theory for fluids described by the
Herschel–Bulkley constitutive law, and provide a variety of solutions to the reduced
equation, both numerical and analytical. For extruded inclined domes, we derive the
characteristic temporal behaviour of measures of the dome's dimensions.
The existence of Rayleigh–Bloch surface waves
Authors: LINTON C. M. , McIVER M.
Published: November 2002

Rayleigh–Bloch surface waves arise in many physical contexts including water waves
and acoustics. They represent disturbances travelling along an infinite periodic structure. In the absence of any existence results, a number of authors have previously
computed such modes for certain specific geometries. Here we prove that such waves
can exist in the absence of any incident wave forcing for a wide class of structures.
On Sex, Drugs and Good Manners: Raja Ali Haji as Lexicographer
Authors: van der Putten Jan
Published: November 2002

The first monolingual Malay dictionary was compiled by Raja Ali Haji out of concern that the Malay language and culture were in a process of ongoing degeneration. He also included words referring to sex and bodily functions so that Malays would know when and where not to use them. The dictionary is thus a refreshing alternative to somewhat Victorian-inspired dictionaries from the nineteenth century.
In this ready-to-live world street design is a major issue. The Clean Street Paradox
Authors: Kenniff Thomas-Bernard
Published: November 2002

In the Berkeley Prize essay
competition for 2002 (see p119),
architecture students were asked to
consider the role of the street in
fostering public life by addressing the
following Question:

Throughout history, the Street has
served as a mediator between our
public and private lives. With rapid
change occurring today in every culture,
the traditional social value of the street
is also undergoing change and in many
instances is losing this human element.
As an architect, how do you address
this issue?

A third year student at the University of Waterloo,
Thomas-Bernard Kenniff, was awarded the prize for the following essay.
Superoxide anions mediate veratridine‐induced cytochrome c release and caspase activity in bovine chromaffin cells
Authors: Jordán Joaquín , Galindo María F , Tornero Daniel , Benavides Amparo , González Constancio , Agapito María T , González‐Garcia Carmen , Ceña Valentín
Published: November 2002

Mitochondrial mechanisms involved in veratridine‐induced chromaffin cell death have been explored.

Exposure to veratridine (30 μM, 1 h) produces cytochrome c release to the cytoplasm that seems to be mediated by superoxide anions and that is blocked by cyclosporin A (10 μM), MnTBAP (10 nM), catalase (100 IU ml−1) and vitamin E (50 μM).

Following veratridine treatment, there is an increase in caspase‐like activity, blocked by vitamin E (50 μM) and the mitochondrial permeability transition pore blocker cyclosporin A (10 μM).

Superoxide anions open the mitochondrial permeability transition pore in isolated mitochondria, an effect that is blocked by vitamin E (50 μM) and cyclosporin A (10 μM), but not by the Ca2+ uniporter blocker ruthenium red (5 μM).

These results strongly suggest that under the stress situation caused by veratridine, superoxide anions become important regulators of mitochondrial function in chromaffin cells.

Exposure of isolated bovine chromaffin mitochondria to Ca2+ results in mitochondrial swelling. This effect was prevented by ruthenium red (5 μM) and cyclosporin A (10 μM), while it was not modified by vitamin E (50 μM).

Veratridine (30 μM, 1 h) markedly decreased total glutathione and GSH content in bovine chromaffin cells.

In conclusion, superoxide anions seem to mediate veratridine‐induced cytochrome c release, decrease in total glutathione, caspase activation and cell death in bovine chromaffin cells.

British Journal of Pharmacology (2002) 137, 993–1000. doi:10.1038/sj.bjp.0704953
The intracellular pathway of the acetylcholine‐induced contraction in cat detrusor muscle cells
Authors: An J Y , Yun H S , Lee Y P , Yang S J , Shim J O , Jeong J H , Shin C Y , Kim J H , Kim D S , Sohn U D
Published: November 2002

The present study was aimed to investigate intracellular pathways involved in acetylcholine (ACh)‐induced contraction in cat detrusor muscle cells

Contraction was expressed as per cent shortening of length of individually isolated smooth muscle cells obtained by enzymatic digestion. Dispersed intact and permeabilized cells were prepared for the treatment of drugs and antibody to enzymes, respectively. Using Western blot, we confirmed the presence of related proteins.

The maximal contraction to ACh was generated at 10−11 M. This response was preferentially antagonized by M3 muscarinic receptor antagonist ρ‐fluoro‐hexahydrosiladifenidol (ρF‐HSD) but not by the M1 antagonist pirenzepine and the M2 muscarinic receptor antagonist methoctramine. We identified G‐proteins Gq/11, Gs, G0, Gi1, Gi2 and Gi3 in the bladder detrusor muscle. ACh‐induced contraction was selectively inhibited by Gq/11 antibody but not to other G subunit.

The phosphatidylinositol‐specific phospholipase C (PI‐PLC) inhibitor neomycin reduced ACh‐induced contraction. However, the inhibitors of the phospholipase D, the phospholipase A2 and protein kinase C did not attenuate the ACh‐induced contraction. ACh‐induced contraction was inhibited by antibody to PLC‐β1 but not PLC‐β3 and PLC‐γ. Thapsigargin or strontium, which depletes or blocks intracellular calcium release, inhibited ACh‐induced contraction. Inositol 1,4,5‐triphosphate (IP3) receptor inhibitor heparin reduced ACh‐induced contraction.

These results suggest that in cat detrusor muscle contraction induced by ACh is mediated via M3 muscarinic receptor‐dependent activation of Gq/11 and PLC‐β1 and IP3‐dependent Ca2+ release.

British Journal of Pharmacology (2002) 137, 1001–1010. doi:10.1038/sj.bjp.0704954
Effects of the selective inhibition of platelet thromboxane synthesis on the platelet‐subendothelium interaction
Authors: De La Cruz J P , Villalobos M A , Escalante R , Guerrero A , Arrebola M M , Sánchez de la Cuesta F
Published: November 2002

Drugs that inhibit TxA2 synthesis are used to reduce platelet aggregation. The aim of this study was to compare the effects of a cyclo‐oxygenase (COX) inhibitor (acetylsalicylic acid, ASA), a thromboxane synthetase (TxS) inhibitor (dazoxiben) and a dual TxS inhibitor and TxA2 receptor blocker (DT‐TX 30) on platelet aggregation and the platelet‐subendothelium interaction in flow conditions.

The techniques used in this in vitro study were platelet aggregometry in whole blood, and measurement of platelet thromboxane B2 and prostaglandin E2 production and leucocyte production of 6‐keto‐PGF1α. The platelet‐subendothelium interaction was evaluated in rabbit aorta subendothelium preparations exposed to flowing blood at a shear stress of 800 s−1. Morphometric methods were used to calculate the percentage of subendothelium occupied by platelets.

The 50% inhibitory concentration (IC50) of DT‐TX 30 in whole blood was in the range of 10−7 μM (induced with collagen or arachidonic acid) to 10−5 μM (induced with thrombin) or 10−4 (induced with ADP). IC50 values under all experimental conditions were lower with DT–TX 30 than with ASA. For thromboxane B2 the IC50 were: ASA 0.84±0.05 μM, dazoxiben 765±54 μM, DT–TX 30 8.54±0.60 μM. Prostaglandin E2 was inhibited only by ASA (IC50 1.21±0.08 μM). Leucocyte 6‐keto‐PGF1α was inhibited by ASA (IC50 6.58±0.76 μM) and increased by dazoxiben and DT–TX 30. The greatest reduction in percentage subendothelial surface occupied by platelets after blood perfusion was seen after treatment with DT–TX 30 in the range of concentrations that inhibited collagen‐induced platelet aggregation (control group: 31.20±3.8%, DT‐TX 30 at 0.1 μM: 10.71±0.55%, at 1.0 μM: 6.53±0.44%, at 5.0 μM; 1.48±0.07%). All three drugs reduced thrombus formation, although ASA (unlike dazoxiben or DT–TX 30) increased the percentage surface occupied by adhesions.

In conclusion, the effect of specific blockage of TxS together with blockage of membrane receptors for TxA2 can surpass the effect of ASA in inhibiting the platelet‐subendothelium interaction in flow conditions.

British Journal of Pharmacology (2002) 137, 1082–1088. doi:10.1038/sj.bjp.0704963
Mechanism of nicotine‐evoked release of [3H]‐noradrenaline in human cerebral cortex slices
Authors: Woo Ran‐Sook , Park Eun‐Young , Shin Min‐Soo , Jeong Min‐Suk , Zhao Rong‐Jie , Shin Byuong‐Soo , Kim Chul‐Jin , Park Jin‐Woo , Kim Kee‐Won
Published: November 2002

The mechanism of stimulation of noradrenaline (NA) release by nicotine (NIC) was investigated in human cerebral cortex slices preloaded with [3H]‐noradrenaline.

NIC (10–1000 μM) increased [3H]‐NA release in a concentration‐dependent manner.

NIC (100 μM)‐evoked [3H]‐NA release was largely dependent on external Ca2+, and was attenuated by ω‐conotoxin GVIA (0.1 μM) but not by nitrendipine (1 μM).

Tetrodotoxin (1 μM) and nisoxetine (0.1 μM) attenuated the NIC (100 μM)‐evoked release of [3H]‐NA.

Mecamylamine (10 μM), dihydro‐β‐erythroidine (10 μM) and d‐tubocurarine (30 μM), but not α‐bungarotoxin (α‐BTX, 0.1 μM), attenuated the NIC (100 μM)‐evoked release of [3H]‐NA.

NIC (100 μM)‐evoked release of [3H]‐NA was not affected by 6‐cyano‐7‐nitroquinoxaline‐2,3‐dione (CNQX, 30 μM) and D(−)‐2‐amino‐5‐phosphonopentanoic acid (D‐AP5, 100 μM), but attenuated by MK‐801 (10 μM). MK‐801 (0.1–1000 μM) displaced the specific binding of [3H]‐nisoxetine with Ki values of 91.2 μM. NIC (100, 300 and 1000 μM) did not induce [3H]‐D‐aspartate release in human cerebral cortex slices.

NIC (100 μM)‐evoked release of [3H]‐NA was attenuated by 7‐nitroindazole (10 μM), NG‐nitro‐L‐arginine methyl ester HCl (L‐NAME, 30 μM), NG‐monomethyl‐L‐arginine acetate (L‐NMMA, 300 μM). [3H]‐NA release induced by NIC (100 μM) was attenuated by methylene blue (3 μM) and 1H‐[1,2,4]oxadiazole[4,3‐α]quinoxalin‐1‐one (ODQ, 10 μM), and enhanced by zaprinast (30 μM).

In conclusion, NIC stimulates the release of [3H]‐NA through activation of α‐BTX‐insensitive nicotinic acetylcholine receptors in the human cerebral cortex slices and this action of NIC is associated with modulation of the NO/cGMP pathway.

British Journal of Pharmacology (2002) 137, 1063–1070. doi:10.1038/sj.bjp.0704975
Cag pathogenicity island-specific responses of gastric epithelial cells to
Helicobacter pylori
infection
Authors: Guillemin Karen , Salama Nina R. , Tompkins Lucy S. , Falkow Stanley
Published: November 2002

Helicobacter pylori
infects over half the world's population and causes a wide range of diseases, including gastritis, peptic ulcer, and two forms of gastric cancer.
H. pylori
infection elicits a variety of phenotypic responses in cultured gastric epithelial cells, including the expression of proinflammatory genes and changes in the actin cytoskeleton. Both of these responses are mediated by the type IV secretion system (TFSS) encoded by the
cag
pathogenicity island (
cag
PAI
). We used human cDNA microarrays to examine the temporal transcriptional profiles of gastric AGS cells infected with
H. pylori
strain G27 and a panel of isogenic mutants to dissect the contributions of various genes in the
cag
PAI
. Infection with G27 induced expression of genes involved in the innate immune response, cell shape regulation, and signal transduction. A mutant lacking the
cagA
gene, which encodes an effector molecule secreted by the TFSS and required for the host cell cytoskeletal response, induced the expression of fewer cytoskeletal genes. A mutant lacking
cagE
, which encodes a structural component of the TFSS, failed to up-regulate a superset of host genes, including the
cagA
-dependent genes, and many of the immune response genes. A mutant lacking the entire
cag
PAI
failed to induce both the
cagE
-dependent genes and several transiently expressed
cagE
independent genes. Host cell transcriptional profiling of infection with isogenic strains offered a detailed molecular picture of
H. pylori
infection and provided insight into potential targets of individual virulence determinants such as tyrosine kinase and Rho GTPase signaling molecules.
RETRACTED: Estrogen receptor-interacting protein that modulates its nongenomic activity-crosstalk with Src/Erk phosphorylation cascade
Authors: Wong Chi-Wai , McNally Christopher , Nickbarg Elliot , Komm Barry S. , Cheskis Boris J.
Published: November 2002

Numerous studies have demonstrated that estrogens induce rapid and transient activation of the Src/Erk phosphorylation cascade. Activation of this cascade triggers vital cellular functions including cell proliferation and differentiation. However, the details of the molecular mechanism of this process remain to be elucidated. We have identified a previously uncharacterized nuclear receptor-interacting protein designated as modulator of nongenomic activity of estrogen receptor (MNAR). Here we show that MNAR modulates estrogen-receptor (ER) interaction with members of the Src family of tyrosine kinases, which leads to a stimulation of Src enzymatic activity and activation of Erk1 and Erk2 kinases. We also show that MNAR, through activation of the Src/Erk phosphorylation cascade, affects ER transcriptional activity and ultimately ER-mediated gene expression. These data reveal that MNAR mediates the crosstalk between two important classes of signal transducing molecules and suggest that ER “genomic” and “nongenomic” activities are interrelated.
The phage λ CII transcriptional activator carries a C-terminal domain signaling for rapid proteolysis
Authors: Kobiler Oren , Koby Simi , Teff Dinah , Court Donald , Oppenheim Amos B.
Published: November 2002

ATP-dependent proteases, like FtsH (HflB), recognize specific protein substrates. One of these is the λ CII protein, which plays a key role in the phage lysis-lysogeny decision. Here we provide evidence that the conserved C-terminal end of CII acts as a necessary and sufficient cis-acting target for rapid proteolysis. Deletions of this conserved tag, or a mutation that confers two aspartic residues at its C terminus do not affect the structure or activity of CII. However, the mutations abrogate CII degradation by FtsH. We have established an
in vitro
assay for the λ CIII protein and demonstrated that CIII directly inhibits proteolysis by FtsH to protect CII and CII mutants from degradation. Phage λ carrying mutations in the C terminus of CII show increased frequency of lysogenization, which indicates that this segment of CII may itself be sensitive to regulation that affects the lysis-lysogeny development. In addition, the region coding for the C-terminal end of CII overlaps with a gene that encodes a small antisense RNA called OOP. We show that deletion of the end of the
cII
gene can prevent OOP RNA, supplied in trans, interfering with CII activity. These findings provide an example of a gene that carries a region that modulates stability at the level of mRNA and protein.
Expression profiling of CD34
+
hematopoietic stem/ progenitor cells reveals distinct subtypes of therapy-related acute myeloid leukemia
Authors: Qian Zhijian , Fernald Anthony A. , Godley Lucy A. , Larson Richard A. , Le Beau Michelle M.
Published: November 2002

One of the most serious consequences of cytotoxic cancer therapy is the development of therapy-related acute myeloid leukemia (t-AML), a neoplastic disorder arising from a multipotential hematopoietic stem cell. To gain insights into the molecular basis of this disease, we performed gene expression profiling of CD34
+
hematopoietic progenitor cells from t-AML patients. Our analysis revealed that there are distinct subtypes of t-AML that have a characteristic gene expression pattern. Common to each of the subgroups are gene expression patterns typical of arrested differentiation in early progenitor cells. Leukemias with a –5/del(5q) have a higher expression of genes involved in cell cycle control (
CCNA2
,
CCNE2
,
CDC2
), checkpoints (
BUB1
), or growth (
MYC
), and loss of expression of the gene encoding IFN consensus sequence-binding protein (
ICSBP
). A second subgroup of t-AML is characterized by down-regulation of transcription factors involved in early hematopoiesis (TAL1, GATA1, and EKLF) and overexpression of proteins involved in signaling pathways in myeloid cells (FLT3) and cell survival (BCL2). Establishing the molecular pathways involved in t-AML may facilitate the identification of selectively expressed genes that can be exploited for the development of urgently needed targeted therapies.
A previously undescribed chemical link between smoking and metabolic disease
Authors: Dickerson Tobin J. , Janda Kim D.
Published: November 2002

Over the past 20 years, protein glycation has been implicated in a variety of pathological states. Although smoking also can contribute to many of these diseases, the precise mechanism by which this occurs is not known. Previously, we have demonstrated that nornicotine, a constituent of tobacco and metabolite of nicotine, can catalyze aldol reactions under aqueous conditions. This finding has caused us to question whether this reaction has physiological consequences. We now report that nornicotine causes aberrant protein glycation and catalyzes the covalent modification of certain prescription drugs such as the commonly used steroid, prednisone. Furthermore, we show that the plasma of smokers as compared with nonsmokers contains higher concentrations of nornicotine-modified proteins, suggesting an unrecognized pathway for the development of the pathology of tobacco abuse.
Laminar specificity of functional MRI onset times during somatosensory stimulation in rat
Authors: Silva Afonso C. , Koretsky Alan P.
Published: November 2002

The blood oxygenation level-dependent (BOLD) response to somatosensory stimulation was measured in α-chloralose-anesthetized rats. BOLD fMRI was obtained at 40-ms temporal resolution and spatial resolution of 200 × 200 × 2,000 μm
3
by using a gated activation paradigm in an 11.7 T MRI. Results show a consistent heterogeneity of fMRI onset times and amplitudes. The earliest onset time (0.59 ± 0.17 s,
n
= 9) corresponded anatomically to layer IV, with superficial and deeper layers starting significantly later (1.27 ± 0.43 s in layers I–III, and 1.11 ± 0.45 s in layer VI). The amplitude of BOLD signal changes also varied with the cortical depth from the pial surface. Changes in the supragranular layers (8.3%) were 44% bigger than changes in the intermediate layers (5.5%), located only ≈700 μm below, and 144% larger than the bottom layer (3.5%), located ≈1.4 mm below the pial surface. The data presented demonstrate that BOLD signal changes have distinct amplitude and temporal characteristics, which vary spatially across cortical layers.
Neuroendocrine control of a sexually dimorphic behavior by a few neurons of the pars intercerebralis in
Drosophila
Authors: Belgacem Yesser Hadj , Martin Jean-René
Published: November 2002

In
Drosophila
, locomotor activity is sexually dimorphic and the brain area controlling this dimorphism has been mapped. The neurons of the pars intercerebralis (PI) have been suggested to participate in such differences between males and females. However, the precise physical nature of the dimorphism, the identity of the PI neurons involved, and the nature of the neuronal signal coding the dimorphism remain unknown. In this study, we used a video-tracking paradigm to characterize further the pattern of locomotor activity in
Drosophila
. We show that the number of activity/inactivity periods (start/stop bouts) is also sexually dimorphic, and that it can be genetically feminized in males. Moreover, the transplantation of PI neurons from a female, or of feminized PI neurons from a donor male into a receiver wild-type male is sufficient to induce the feminization of locomotor behavior, confirming that this tiny cluster of ≈10 neurons is directly responsible for the sexual dimorphism in locomotor activity. Finally, feeding males with fluvastatin, a juvenile hormone (JH) inhibitor, also led to start/stop feminization, and this effect is reversible by the simultaneous application of methoprene, a JH analog, suggesting the existence of a neuroendocrine control, by JH, of such behavioral dimorphism.
Distinct neural systems subserve person and object knowledge
Authors: Mitchell Jason P. , Heatherton Todd F. , Macrae C. Neil
Published: November 2002

Studies using functional neuroimaging and patient populations have demonstrated that distinct brain regions subserve semantic knowledge for different classes of inanimate objects (e.g., tools, musical instruments, and houses). What this work has yet to consider, however, is how conceptual knowledge about people may be organized in the brain. In particular, is there a distinct functional neuroanatomy associated with person knowledge? By using event-related functional magnetic resonance imaging (fMRI), we measured neural activity while participants made semantic judgments about people or objects. A unique pattern of brain activity was associated with person judgments and included brain regions previously implicated in other aspects of social-cognitive functioning: medial prefrontal cortex, superior temporal cortex, intraparietal sulcus, and fusiform gyrus. These regions were generally marked by relatively little change from baseline brain activity for person judgments along with significant deactivations for object judgments. Together, these findings support the notion that person knowledge may be functionally dissociable from other classes of semantic knowledge within the brain.
A viral suppressor of RNA silencing differentially regulates the accumulation of short interfering RNAs and micro-RNAs in tobacco
Authors: Mallory Allison C. , Reinhart Brenda J. , Bartel David , Vance Vicki B. , Bowman Lewis H.
Published: November 2002

Two major classes of small noncoding RNAs have emerged as important regulators of gene expression in eukaryotes, the short interfering RNAs (siRNAs) associated with RNA silencing and endogenous micro-RNAs (miRNAs) implicated in regulation of gene expression. Helper component-proteinase (HC-Pro) is a viral protein that blocks RNA silencing in plants. Here we examine the effect of HC-Pro on the accumulation of siRNAs and endogenous miRNAs. siRNAs were analyzed in transgenic tobacco plants silenced in response to three different classes of transgenes: sense-transgenes, inverted-repeat transgenes, and amplicon-transgenes. HC-Pro suppressed silencing in each line, blocking accumulation of the associated siRNAs and allowing accumulation of transcripts from the previously silenced loci. HC-Pro-suppression of silencing in the inverted-repeat- and amplicon-transgenic lines was accompanied by the apparent accumulation of long double-stranded RNAs and proportional amounts of small RNAs that are larger than the siRNAs that accumulate during silencing. Analysis of these results suggests that HC-Pro interferes with silencing either by inhibiting siRNA processing from double-stranded RNA precursors or by destabilizing siRNAs. In contrast to siRNAs, the accumulation of endogenous miRNAs was greatly enhanced in all of the HC-Pro-expressing lines. Thus, our results demonstrate that accumulation of siRNAs and miRNAs in plants can be differentially regulated by a viral protein. The fact that HC-Pro affects the miRNA pathway raises the possibility that this pathway is targeted by plant viruses as a means to control gene expression in the host.
Metabolic specialization associated with phenotypic switching inCandidaalbicans
Authors: Lan Chung-Yu , Newport George , Murillo Luis A. , Jones Ted , Scherer Stewart , Davis Ronald W. , Agabian Nina
Published: November 2002

Phase and antigenic variation are mechanisms used by microbial pathogens to stochastically change their cell surface composition. A related property, referred to as phenotypic switching, has been described for some pathogenic fungi. This phenomenon is best studied inCandida albicans, where switch phenotypes vary in morphology, physiology, and pathogenicity in experimental models. In this study, we report an application of a custom Affymetrix GeneChip representative of the entireC. albicansgenome and assay the global expression profiles of white and opaque switch phenotypes of the WO-1 strain. Of 13,025 probe sets examined, 373 ORFs demonstrated a greater than twofold difference in expression level between switch phenotypes. Among these, 221 were expressed at a level higher in opaque cells than in white cells; conversely, 152 were more highly expressed in white cells. Affected genes represent functions as diverse as metabolism, adhesion, cell surface composition, stress response, signaling, mating type, and virulence. Approximately one-third of the differences between cell types are related to metabolic pathways, opaque cells expressing a transcriptional profile consistent with oxidative metabolism and white cells expressing a fermentative one. This bias was obtained regardless of carbon source, suggesting a connection between phenotypic switching and metabolic flexibility, where metabolic specialization of switch phenotypes enhances selection in relation to the nutrients available at different anatomical sites. These results extend our understanding of strategies used in microbial phase variation and pathogenesis and further characterize the unanticipated diversity of genes expressed in phenotypic switching.
A cell-free protein synthesis system for high-throughput proteomics
Authors: Sawasaki Tatsuya , Ogasawara Tomio , Morishita Ryo , Endo Yaeta
Published: November 2002

We report a cell-free system for the high-throughput synthesis and screening of gene products. The system, based on the eukaryotic translation apparatus of wheat seeds, has significant advantages over other commonly used cell-free expression systems. To maximize the yield and throughput of the system, we optimized the mRNA UTRs, designed an expression vector for large-scale protein production, and developed a new strategy to construct PCR-generated DNAs for high-throughput production of many proteins in parallel. The resulting system achieves high-yield expression and can maintain productive translation for 14 days. Additionally, in the integration of a PCR-directed system for template creation, at least 50 genes can be translated in parallel, yielding between 0.1 and 2.3 mg of protein by one person within 2 days. Assessment of correct protein folding by the products of this high-throughput protein-expression system were performed by enzymatic assays of kinases and by NMR spectroscopic analysis. The cell-free system, reported here, bypasses many of the time-consuming cloning steps of conventional expression systems and lends itself to a robotic automation for the high-throughput expression of proteins.
Engineered herpes simplex virus 1 is dependent on IL13Rα2 receptor for cell entry and independent of glycoprotein D receptor interaction
Authors: Zhou Guoying , Ye Guo-Jie , Debinski Waldemar , Roizman Bernard
Published: November 2002

In the first stage of engineering a herpes simplex virus (HSV)-1 that specifically targets human malignant glioma cells, we constructed a recombinant virus designated R5111 in which we have ablated the binding sites for sulfated proteoglycans in glycoproteins B and C, replaced the amino-terminal 148 aa in glycoprotein C by IL-13 flanked at its amino terminus with a signal peptide, and inserted a second copy of IL-13 after the amino acid 24 of glycoprotein D. In the process, the binding site for HveA, a viral entry receptor, was disrupted. We have also transformed a cell line (J1.1) lacking HSV-1 receptors to express IL13Rα2 receptor (J13R cells). We report the following: the R5111 recombinant virus replicates as well as wild-type virus in a variety of cell lines including cell lines derived from brain tumors. R5111 failed to replicate in the parent J1.1 cell line but multiplied to titers similar to those obtained in other cell lines in the J13R cell line. On the basis of the evidence that R5111 can use the IL13Rα2 receptor for entry, we conclude that HSV-1 can use receptors other than HveA or nectins, provided it can bind to them. The domains of gD that interact with HveA and nectin receptors are independent of each other. Lastly, the fusogenic activities of the glycoproteins in the viral envelope are not dependent on a set of unique interactions between glycoprotein D and its receptor. The construction of R5111 opens the way for construction of viruses totally dependent on selected receptors for entry or imaging of targeted cells.
Down-regulation of parkin protein in transient focal cerebral ischemia: A link between stroke and degenerative disease?
Authors: Mengesdorf Thorsten , Jensen Poul H. , Mies Günter , Aufenberg Christoph , Paschen Wulf
Published: November 2002

Ubiquitylated protein aggregates are characteristic features of neurodegenerative disorders that are also found in acute pathological states of the brain such as stroke. Many of the proteins connected to neurodegenerative diseases play a role in the ubiquitin-proteasomal pathway. Mutation of one of these proteins, the E3 ubiquitin ligase parkin, is the cause of autosomal recessive juvenile Parkinson's disease. Here we show that transient focal cerebral ischemia of 1-h duration induces marked depletion of parkin protein levels, to 60%, 36%, 33%, and 25% of controls after 1, 3, 6, and 24 h of reperfusion, but that ischemia does not cause lower protein levels of E2 ubiquitin-conjugating enzymes Ubc6, Ubc7, or Ubc9. After 3 h of reperfusion, when parkin protein levels were already reduced to <40% of control, ATP levels were almost completely recovered from ischemia and we did not observe DNA fragmentation, suggesting that parkin depletion preceded development of neuronal cell death. Up-regulation of the expression of parkin has been shown to protect cells from injury induced by endoplasmic reticulum (ER) dysfunction, and this form of cellular stress is also triggered by transient cerebral ischemia. However, in contrast to observations in neuroblastoma cells, we saw no up-regulation of parkin expression in primary neuronal cell cultures after induction of ER dysfunction. Our data thus suggest that ischemia-induced depletion of parkin protein may contribute to the pathological process resulting in cell injury by increasing the sensitivity of neurons to ER dysfunction and the aggregation of ubiquitylated proteins during the reperfusion period.
The inflationary effects of environmental fluctuations in source–sink systems
Authors: Gonzalez Andrew , Holt Robert D.
Published: November 2002

Ecological communities are open to the immigration of individuals and are variable through time. In open habitats immigration may permit populations of a species to persist locally even though local biotic and abiotic processes tend to exclude such “sink” populations. A general model for a sink population reveals that autocorrelated environmental variation can dramatically inflate local abundance and that such populations display a characteristic “outbreak” pattern. An experimental protist microcosm exhibits these predicted effects. Because the many ecological and environmental processes that set the rate of exclusion are typically autocorrelated, these theoretical and empirical results have broad implications for our understanding of community structure and highlight a previously unsuspected potential effect of anthropogenic climate change.