bluuebunny/crossref_metadata_2025 huggingface dataset:
Gene expression profiling of whole-blood samples from women exposed to hormone replacement therapy
Authors: Dumeaux Vanessa , Johansen Jostein , Børresen-Dale Anne-Lise , Lund Eiliv
Published: April 2006

The American Women's Health Initiative study published in July 2002 caused considerable concern among hormone replacement therapy (HRT) users and prescribers in many countries. This study is an exploratory research comparing the genome-wide expression profile in whole-blood samples according to HRT use. Within the Norwegian Women and Cancer study, 100 postmenopausal women (50 HRT users and 50 non-HRT users) born between 1943 and 1949 with normal to high body mass index and no other medication use were selected. After total RNA extraction, amplification, and labeling, the samples were hybridized together with a common reference (Universal human reference RNA, Stratagen) to Agilent Human 1A oligoarrays (G4110b, Agilent Technologies) containing 20,173 unique genes. Differentially expressed genes were used to build a classifier using the nearest shrunken centroid method (PAM). Then, we tested the significant changes in single genes by different methods like t test, Significance Analysis of Microarrays, and Bayesian ANOVA analysis. Results did not reveal any distinct gene list which predicted accurately HRT exposure (error rate, 0.40). Classifier performance slightly improved (error rate, 0.26) including only women who were using continuous combined HRT treatment. According to the small amplitude of expression alterations observed in whole blood, more quantitative technique and larger sample sizes will be needed to be able to investigate whether significant single genes are differentially expressed in HRT versus non-HRT users. Taken cautiously, significant enrichments in biological process of genes with small changes after HRT use were observed (e.g., receptor and transporter activities, immune response, frizzled signaling pathway, actin filament organization, and glycogen metabolism). [Mol Cancer Ther 2006;5(4):868–76]
Aerosol delivery of urocanic acid–modified chitosan/programmed cell death 4 complex regulated apoptosis, cell cycle, and angiogenesis in lungs of K-ras null mice
Authors: Jin Hua , Kim Tae Hee , Hwang Soon-Kyung , Chang Seung-Hee , Kim Hyun Woo , Anderson Hanjo K. , Lee Han-Woong , Lee Kee-Ho , Colburn Nancy H. , Yang Hsin-Sheng , Cho Myung-Haing , Cho Chong Su
Published: April 2006

The low efficiency of conventional therapies in achieving long-term survival of patients with lung cancer calls for development of novel treatment options. Although several genes have been investigated for their antitumor activities through gene delivery, problems surrounding the methods used, such as efficiency, specificity, and toxicity, hinder application of such therapies in clinical settings. Aerosol gene delivery as nonviral and noninvasive method for gene therapy may provide an alternative for a safer and more effective treatment for lung cancer. In this study, imidazole ring-containing urocanic acid–modified chitosan (UAC) designed in previous study was used as a gene carrier. The efficiency of UAC carrier in lungs was confirmed, and the potential effects of the programmed cell death protein 4 (PDCD4) tumor suppressor gene on three major pathways (apoptosis, cell cycle, and angiogenesis) were evaluated. Aerosol containing UAC/PDCD4 complexes was delivered into K-ras null lung cancer model mice through the nose-only inhalation system developed by our group. Delivered UAC/PDCD4 complex facilitated apoptosis, inhibited pathways important for cell proliferation, and efficiently suppressed pathways important for tumor angiogenesis. In summary, results obtained by Western blot analysis, immunohistochemistry, and terminal deoxynucleotidyl transferase–mediated nick end labeling assay suggest that our aerosol gene delivery technique is compatible with in vivo gene delivery and can be applied as a noninvasive gene therapy. [Mol Cancer Ther 2006;5(4):1041–9]
Molecular alterations after Polo-like kinase 1 mRNA suppression versus pharmacologic inhibition in cancer cells
Authors: Schmidt Mathias , Hofmann Hans-Peter , Sanders Karl , Sczakiel Georg , Beckers Thomas L. , Gekeler Volker
Published: April 2006

Multiple roles within mitosis have been assigned to Polo-like kinase 1 (Plk1), making it an attractive candidate for mitotic targeting of cancer cells. We have employed chimeric antisense oligonucleotides to investigate the molecular alterations after targeted interference with Plk1 in RKO human colon adenocarcinoma and PC3 prostate cancer cells. Suppression of Plk1 mRNA resulted in a dramatic increase of the mitotic index followed by the onset of apoptosis. Mitotically arrested cells displayed randomly separated condensed chromosomes and the occurrence of multiple spindle poles with well-formed asters. Induction of apoptosis was strictly dependent on cell cycle progression: Genetically engineered RKO cells with inducible expression of the cyclin-dependent kinase inhibitor p27Kip1 were completely refractory to Plk1 depletion-induced apoptosis when they were arrested in the G1 phase of the cell cycle. Various mitotic markers, including MPM-2, cdc25c, cyclin B1, or phosphorylated histone H3, were investigated to explore the molecular consequences of Plk1 depletion. Whereas most marker proteins showed similar alterations compared with treatment with paclitaxel, cdc25c was fully phosphorylated solely in paclitaxel-treated cells but only partially phosphorylated in Plk1-depleted cells, although both treatments caused a profound mitotic arrest. This differential phosphorylation of cdc25c was used to test whether a pharmacologic inhibitor of Plk1 would exert the same cellular effects as interference with Plk1 on a mRNA level. It was found that the differential electrophoretic mobility of cdc25c can serve as a reliable molecular marker to track inhibition of Plk1 by small-molecule inhibitors within a cell. [Mol Cancer Ther 2006;5(4):809–17]
Mode of action of the chloroethylating and carbamoylating moieties of the prodrug cloretazine
Authors: Ishiguro Kimiko , Seow Helen A. , Penketh Philip G. , Shyam Krishnamurthy , Sartorelli Alan C.
Published: April 2006

Cloretazine is an antitumor sulfonylhydrazine prodrug that generates both chloroethylating and carbamoylating species. The cytotoxic potency of these species was analyzed in L1210 leukemia cells using analogues with chloroethylating or carbamoylating function only. Clonogenic assays showed that the chloroethylating-only agent 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)hydrazine (90CE) produced marked differential cytotoxicity against wild-type and O6-alkylguanine-DNA alkyltransferase–transfected L1210 cells (LC10, 1.4 versus 31 μmol/L), indicating that a large portion of the cytotoxicity was due to alkylation of DNA at the O-6 position of guanine. Consistent with the concept that O-6 chloroethylation of DNA guanine progresses to interstrand cross-links, the comet assay, in which DNA cross-links were measured by a reduction in DNA migration induced by strand breaks, showed that cloretazine and 90CE, but not the carbamoylating-only agent 1,2-bis(methylsulfonyl)-1-[(methylamino)carbonyl]hydrazine (101MDCE), produced DNA cross-links and that cloretazine caused more DNA cross-links than 90CE at equimolar concentrations. Cell cycle analyses showed that 90CE and 101MDCE at concentrations of 5 and 80 μmol/L, respectively, produced similar degrees of G2-M arrest. 90CE produced selective inhibition of DNA synthesis after overnight incubation, whereas 101MDCE caused rapid and nonselective inhibition of RNA, DNA, and protein syntheses. Both 90CE and 101MDCE induced phosphorylation of histone H2AX, albeit with distinct kinetics. These results indicate that (a) differential expression of O6-alkylguanine-DNA alkyltransferase in tumor and host cells seems to be responsible for tumor selectivity exerted by cloretazine; (b) 101MDCE enhances DNA cross-linking activity; and (c) 90CE induces cell death at concentrations lower than those causing alterations in the cell cycle and macromolecular syntheses. [Mol Cancer Ther 2006;5(4):969–76]
Molecular biomarkers: their increasing role in the diagnosis, characterization, and therapy guidance in pancreatic cancer
Authors: Jimeno Antonio , Hidalgo Manuel
Published: April 2006

The rapidly expanding knowledge of the pathogenesis of pancreatic cancer at the molecular level is providing new targets for disease characterization, early diagnosis, and drug discovery and development. Gene mutation analysis has provided insight on the pathogenesis and progression from preinvasive lesions to invasive cancer. Gene and protein expression profiling has advanced our understanding of pancreatic ductal adenocarcinoma identifying genes that are highly expressed in pancreatic cancers, providing more insight into the clinicopathologic features of pancreatic cancer, and revealing novel features related to the process of tissue invasion by these tumors. The increasing knowledge of the pathway activation profile in pancreatic cancer is yielding new targets but also new markers to select patients and guide and predict therapy efficacy. The discovery of genetic factors of which the presence predisposes pancreatic cancer to successful targeting, such as the association of BRCA2/Fanconi anemia genes defects and sensitivity to mitomycin C, will eventually lead to a more individualized treatment approach. In summary, several decades of intensive research have originated multiple factors or biomarkers that are likely to be helpful in the diagnosis, characterization, and therapy selection of pancreatic cancer patients. A deep understanding of the relative relevance of each biomarker will be key to efficiently diagnose this disease and direct our patients towards the drugs more likely to be of benefit based on their particular profile. The development of new preclinical models is of paramount importance to achieve these goals. [Mol Cancer Ther 2006;5(4):787–96]
p53-Independent Apoptosis Disrupts Early Organogenesis in Embryos Lacking Both Ataxia-Telangiectasia Mutated and Prkdc
Authors: Gladdy Rebecca A. , Nutter Lauryl M.J. , Kunath Tilo , Danska Jayne S. , Guidos Cynthia J.
Published: April 2006

The ataxia-telangiectasia mutated (ATM) protein and the nonhomologous end-joining (NHEJ) pathway play crucial roles in sensing and repairing DNA double-strand breaks in postnatal cells. However, each pathway is dispensable for early embryogenesis. Loss of both ATM and Prkdc/Ku is synthetically lethal, but neither the developmental processes perturbed nor the mechanisms of lethality have been determined by previous reports. Here, we show that ATM and Prkdc collaborate to maintain genomic stability during gastrulation and early organogenesis, a period of rapid proliferation and hypersensitivity to DNA damage. At E7.5 to E8.5, ATM−/−Prkdcscid/scid embryos displayed normal proliferation indices but exhibited excessive apoptosis and elevated expression of Ser15-phosphorylated p53. Thus, this crucial regulatory residue of p53 can be phosphorylated in the absence of ATM or Prkdc. However, loss of p53 did not abrogate or delay embryonic lethality, revealing that apoptosis is p53 independent in these in ATM−/−Prkdcscid/scid embryos. Because mice with combined disruptions of ATM and other NHEJ components (ligase IV, Artemis) are viable, our data suggest a novel NHEJ-independent function for Prkdc/Ku that is required to complete early embryogenesis in the absence of ATM. (Mol Cancer Res 2006;4(5):311–8)
The Islamic Nature of the Saudi Regulations for Companies
Authors: Koraytem
Published: May 2006

No Abstract
Vicarious Liability: A Study of the Liability of Employer and Employee in the Islamic Law of Tort
Authors: Basir bin Mohamad
Published: May 2006

No Abstract
The Operation of Retakaful (Islamic Reinsurance) Protection
Authors: Burhan Arbouna
Published: May 2006

No Abstract
Note on UAE Ministerial Decree No. 612 of 2000
Authors: Al Tamimi & Company
Published: May 2006

No Abstract
The Legal Environment of the Environment in the Gulf
Authors:   Meyer-Reumann
Published: May 2006

No Abstract
Process–microstructure–properties relationship during formation of AlN layers by physical vapour deposition
Authors: Figueroa U. , Salas O. , Oseguera J.
Published: April 2006

The relationship of processing, microstructure and properties during deposition of AlN layers on glass substrates by reactive magnetron sputtering was investigated. The AlN films were prepared with two working gas mixtures: 3 : 1 and 1 : 1 Ar/N2 volume ratios; three working pressure values: 0·2, 0·5 and 0·8 Pa and two target to substrate distances: 2·5 and 3 cm. The resulting films were analysed by scanning electron microscopy and energy dispersive X-ray microanalysis and X-ray diffractometry. In the ranges of processing variables studied, film growth morphology and orientation were mainly affected by working pressure, where deviations from expected behaviour were attributed to process instabilities. No significant influence of gas mixture composition or substrate to target distance was detected in the ranges studied. The effect of pressure was rationalised in terms of the associated energy of the Ar ion film bombardment, which was expected to cause only surface film modifications owing to its low estimated values, but enough to produce structural changes. The development of residual stresses and their effect on hardness and fracture behaviour of the films were mostly influenced by the type of columnar growth and film thickness.
Do trainees follow up their operative cases? An audit of myringoplasty follow-up
Authors: Banga R , Mirza S , Douglas SA , Gibbin KP
Published: April 2006

With the reduction in working hours brought on by Calmanisation and the European Working Time Directive there has been a simultaneous reduction in the number of hours of training received by SpRs. There are also plans to further shorten higher surgical training in the near future. In light of these facts it is important to identify any areas that can maximise training opportunities and learning. There are several papers evaluating training in the theatre and outpatient setting but very few of these include detailed information on the level of follow-up of SpRs' operative cases.
The English College wins the Rosin-Tanner Cup
Authors: Rosin David
Published: April 2006

The Royal College of Surgeons of England rugby club is flourishing but needs your support. It has a very young history when compared with the United Hospitals Cup (the oldest competition, dating back to 1874 and still being played despite many amalgamations of the London teaching hospitals). Our College club was founded in 2003 to play against the Royal College of Surgeons of Edinburgh for the Park–Parker Cup. The first game was played at the Rosslyn Park ground on the morning of the Calcutta Cup and, sadly, after suturing various parts of players' anatomy from both sides, I presented the Cup to the Edinburgh side who had been triumphant, reversing a large half-time lead by the English College. The next two years belonged to England winning in Edinburgh and in London.
Early herbals from the Royal College of Surgeons library
Authors: Craig Tina
Published: April 2006

On 14 March 2006 the British Society for the History of Medicine held its 12th biennial Poynter lecture at the College. It was given by Dr David Allen and entitled 'Remedies from our natural flora: piecing together an under-rated tradition'. Before the lecture delegates were able to view the Hunterian Museum and a selection of the following early herbals were put on display in the library. From various parts of Europe knowledge and techniques were developing and ideas were being shared, sometimes, as this article points out, without due acknowledgement to their originator.
The profession strikes back on selection into training
Authors: Ribeiro Bernard
Published: April 2006

It is rare for the profession to identify a single cause that unites it so firmly as has the selection of its future doctors. Accusations of bias, nepotism and paternalism in the time-honoured method of selection by interview have given way to e-selection in the electronic age.
Orientação sobre saúde bucal em um Centro de Saúde
Authors: Castellanos Roberto Augusto
Published: May 2006

Foi realizado estudo com o fim de verificar qual a orientação sobre saúde bucal dada aos clientes que pela primeira vez compareceram a um centro de saúde. Durante o período de 2 semanas foram observados 25 clientes; o método utilizado foi o da "observação participante''. Os dados necessários para o "diagnóstico educativo" foram colhidos com o auxílio de uma ficha. Da análise destes dados concluiu-se não haver uma adequada orientação com relação à saúde bucal, por parte do pessoal responsável. Sugere-se como "tratamento educativo" revisão das normas em relação à saúde da boca e desenvolvimento de um programa educativo, incidental e planejado, integrado às diferentes atividades realizadas pelo Centro. Propõe-se um conteúdo programático responsabilizando o dentista pelo adestramento do pessoal, execução e avaliação do programa. Ressalta-se a importância do centro de saúde para o desenvolvimento de programas integrados, preventivos, curativos e educativos.
Estudo comparativo entre meios de captação de vapores de mercúrio para avaliação do risco de intoxicação profissional
Authors: Colacioppo Sérgio
Published: May 2006

Estudo comparativo entre os meios de captação de vapores de mercúrio mais viáveis: absorção em permanganato de potássio em meio ácido, absorção em solução de iodo e iodeto, adsorção em carvão ativo e adorção em hopcalita. É descrito um processo de produção de atmosfera padrão de vapores de mercúrio para testar os diferentes meios, e o que maior acuidade e precisão apresentou foi o que utiliza absorção em permanganato em meio ácido.
Entre a saúde coletiva e a saúde mental: um instrumental metodológico para avaliação da rede de Centros de Atenção Psicossocial (CAPS) do Sistema Único de Saúde
Authors: Onocko-Campos Rosana Teresa , Furtado Juarez Pereira
Published: May 2006

Trata-se de discussão preliminar sobre possível instrumental metodológico para pesquisa avaliativa da rede de Centros de Atenção Psicossocial (CAPS) do SUS. Problematiza-se a relevância que a área da saúde mental deveria ter para a saúde coletiva, considerando a alta prevalência de transtornos psíquicos e relativa carência de estudos da interface dessas áreas. Destacam-se as características dos CAPS para demonstrar que são serviços particularmente complexos. Considera-se imprescindível a aproximação das duas áreas para a constituição de um campo interdisciplinar de saberes e práticas, e aponta-se a necessidade dessa convergência para o desenvolvimento de um processo avaliativo sistemático dos CAPS. Levando-se em conta a complexidade do objeto e visando gerar subsídios para a Reforma Psiquiátrica Brasileira, com base em instrumentos da pesquisa avaliativa, propõe-se: a importância de se resgatar a participação de diversos atores no processo avaliativo, a necessidade de coletar e sistematizar diversos estudos desenvolvidos na academia sobre o tema, e a importância de promover um novo território de pesquisa no âmbito das políticas públicas de saúde, que possa subsidiar formuladores, gestores e equipes na reformulação de suas práticas.
Trabalho técnico em laboratórios de pesquisa e desenvolvimento em saúde: um estudo de caso
Authors: Teixeira Mareia de Oliveira , Nunes Tânia C. M. , Mello José Manoel C. de
Published: May 2006

Este artigo pretende discutir algumas questões em torno do processo de trabalho dos técnicos de nível médio, a partir do estudo de dois laboratórios de pesquisa e desenvolvimento (P&D) pertencentes à Fundação Oswaldo Cruz (Fiocruz). Essa discussão, contudo, não pode ser dissociada da análise, mesmo que parcial, dos demais processos de trabalho envolvidos nas atividades de P&D no interior dos laboratórios. Assim, a identificação desses atores, de suas atividades e especificidades é parte constituinte dessa investigação. A partir da incorporação de técnicas de análise de cunho etnográfico, conhecemos as interações entre os diversos atores, suas atividades, além da organização do trabalho no interior dos laboratórios. Através da análise da distribuição de atribuições, e das interações entre os atores, identificamos algumas tendências no(s) processo(s) de trabalho nos laboratórios de P&D em saúde.
Aneurisma tóraco-abdominal inflamatório
Authors: Rocha Eduardo Faccini , Luccas George Carchedi , Baldini Neto Luis
Published: May 2006

Os autores relatam o caso de um paciente apresentando aneurisma tóraco-abdominal tipo IV de etiologia inflamatória. Esse paciente foi submetido à correção cirúrgica eletiva através de incisão tóraco-abdominal, rotação medial das vísceras, com dificuldade, devido às aderências, e utilização de perfusão visceral durante o pinçamento supracelíaco, com um circuito de circulação extracorpórea modificado.
St Paul's Footbridge, Ebbw Vale, Wales—landmark structure
Authors: Williams D. E.
Published: May 2006

The paper outlines the design processes involved in the creation of St Paul's Footbridge, a new landmark footbridge at Ebbw Vale, South Wales. The provision of a landmark footbridge forms part of the council's broader strategy to stimulate recovery and regeneration of this area through delivery of quality urban infrastructure design. Regular effective communication throughout the team, drawing on the creative flair of an artist and practical expertise of contractor and fabricator, resulted in a striking structure being delivered for the Ebbw Valley. The team and framework set up to deliver the footbridge and the constraints affecting the design and construction of the bridge are described. The parameters that affected the design of the deck and its foundations together with the fabrication/erection issues that were encountered are also presented. Finally, some factors to be considered when designing infrastructure projects for disabled access are reported.
Nighttime Evapotranspiration from Alfalfa and Cotton in a Semiarid Climate
Authors: Tolk Judy A. , Howell Terry A. , Evett Steven R.
Published: May 2006

Nighttime evapotranspiration (ETN) has typically been neglected in estimating water loss from land surfaces. Our objective was to quantify the contribution of ETN to daily (24‐h) ET (ET24) of irrigated and dryland cotton (Gossypium hirsutum L.) and irrigated alfalfa (Medicago sativa L.) grown in a semiarid climate. The results were then examined using a Penman–Monteith ET model which separates control of ET into its radiation (equilibrium) and atmospheric demand (imposed) components. Nighttime ET was measured at Bushland, TX using weighing lysimeters containing monolithic soil cores of Pullman clay loam (fine, mixed, superactive thermic Torrertic Paleustoll) for alfalfa in 1998 and cotton in 2001. Measured ratios of ETN to ET24 ranged from an average of 3% for a dryland cotton crop to 7.2% for irrigated alfalfa over a season. In the largest events, ETN was as much as 12% of ET24 with single nighttime losses approaching 2 mm. Model calculations showed that virtually all ETN was the result of imposed atmospheric conditions, primarily vapor pressure deficit. However, ETN was also related to sensible heat transfer to the canopy. Nighttime ET can be an important part of total ET of irrigated crops in a semiarid environment.
Research Designs in Mathematics and Science Education—Continuing the Dialogue
Authors: Schorr Roberta Y.
Published: May 2006

Over the last century, the repertoire and range of research approaches in education have changed dramatically. During the Thorndike era, and well beyond, a wave of enthusiasm for experimentation dominated the field (Campbell & Stanley, 1963; Kilpatrick, 1992; Romberg, 1992).
Extracellular matrix scaffolds are repopulated by bone marrow‐derived cells in a mouse model of achilles tendon reconstruction
Authors: Zantop Thore , Gilbert Thomas W. , Yoder Mervin C. , Badylak Stephen F.
Published: April 2006

The extracellular matrix derived from porcine small intestinal submucosa (SIS‐ECM), an FDA‐approved material currently used clinically for rotator cuff repair, has been shown to attract bone marrow‐derived cells during in vivo remodeling of a subcutaneous implant and produce chemoattractant peptides following chemical degradation in vitro. The purpose of the present study was to determine if bone marrow‐derived cells participate in the long‐term remodeling of the Achilles tendon in a mouse model when repaired with SIS‐ECM. A 2‐mm gap was produced in the Achilles tendon of 40 chimeric mice produced to express green fluorescent protein (GFP) in all of their bone marrow‐derived cells. Tendons were repaired by replacing the resected section with autologous tendon tissue or with a single layer sheet of lyophilized SIS‐ECM. Four animals from each treatment group were sacrificed at 1, 2, 4, 8, and 16 weeks, and sections were harvested for histologic and fluorescence microscopy. Both groups showed accumulation of GFP‐expressing marrow‐derived cells at the site of tendon remodeling at 1 and 2 weeks that were associated with areas of angiogenesis and inflammation. By 16 weeks, the SIS‐ECM‐treated group showed GFP expressing cells throughout the remodeled tendon in the absence of any inflammatory response, while the autologous tendon repair group showed no GFP expressing cells within the tendon except for occasional cells in the lumen of blood vessels. An SIS‐ECM scaffold used for tendon repair recruits a population of bone marrow‐derived cells that participates in the long‐term remodeling process. The ability of SIS‐ECM to recruit a population of marrow‐derived cells to the remodeling site may alter the default mechanism of tendon healing. The involvement of these cells in the remodeling process may explain in part the process of site specific constructive remodeling as opposed to scar tissue formation when the ECM is used as a biologic scaffold for tendon reconstruction. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
Localization of cardiac L-type Ca2+channels to a caveolar macromolecular signaling complex is required for β2-adrenergic regulation
Authors: Balijepalli Ravi C. , Foell Jason D. , Hall Duane D. , Hell Johannes W. , Kamp Timothy J.
Published: April 2006

L-type Ca2+channels play a critical role in regulating Ca2+-dependent signaling in cardiac myocytes, including excitation-contraction coupling; however, the subcellular localization of cardiac L-type Ca2+channels and their regulation are incompletely understood. Caveolae are specialized microdomains of the plasmalemma rich in signaling molecules and supported by the structural protein caveolin-3 in muscle. Here we demonstrate that a subpopulation of L-type Ca2+channels is localized to caveolae in ventricular myocytes as part of a macromolecular signaling complex necessary for β2-adrenergic receptor (AR) regulation of ICa,L. Immunofluorescence studies of isolated ventricular myocytes using confocal microscopy detected extensive colocalization of caveolin-3 and the major pore-forming subunit of the L-type Ca channel (Cav1.2). Immunogold electron microscopy revealed that these proteins colocalize in caveolae. Immunoprecipitation from ventricular myocytes using anti-Cav1.2 or anti-caveolin-3 followed by Western blot analysis showed that caveolin-3, Cav1.2, β2-AR (not β1-AR), G protein αs, adenylyl cyclase, protein kinase A, and protein phosphatase 2a are closely associated. To determine the functional impact of the caveolar-localized β2-AR/Cav1.2 signaling complex, β2-AR stimulation (salbutamol plus atenolol) of ICa,Lwas examined in pertussis toxin-treated neonatal mouse ventricular myocytes. The stimulation of ICa,Lin response to β2-AR activation was eliminated by disruption of caveolae with 10 mM methyl β-cyclodextrin or by small interfering RNA directed against caveolin-3, whereas β1-AR stimulation (norepinephrine plus prazosin) of ICa,Lwas not altered. These findings demonstrate that subcellular localization of L-type Ca2+channels to caveolar macromolecular signaling complexes is essential for regulation of the channels by specific signaling pathways.
Energy landscape view of phase transitions and slow dynamics in thermotropic liquid crystals
Authors: Chakrabarti Dwaipayan , Bagchi Biman
Published: April 2006

Thermotropic liquid crystals are known to display rich phase behavior on temperature variation. Although the nematic phase is orientationally ordered but translationally disordered, a smectic phase is characterized by the appearance of a partial translational order in addition to a further increase in orientational order. In an attempt to understand the interplay between orientational and translational order in the mesophases that thermotropic liquid crystals typically exhibit upon cooling from the high-temperature isotropic phase, we investigate the potential energy landscapes of a family of model liquid crystalline systems. The configurations of the system corresponding to the local potential energy minima, known as the inherent structures, are determined from computer simulations across the mesophases. We find that the depth of the potential energy minima explored by the system along an isochor grows through the nematic phase as temperature drops in contrast to its insensitivity to temperature in the isotropic and smectic phases. The onset of the growth of the orientational order in the parent phase is found to induce a translational order, resulting in a smectic-like layer in the underlying inherent structures; the inherent structures, surprisingly, never seem to sustain orientational order alone if the parent nematic phase is sandwiched between the high-temperature isotropic phase and the low-temperature smectic phase. The Arrhenius temperature dependence of the orientational relaxation time breaks down near the isotropic–nematic transition. We find that this breakdown occurs at a temperature below which the system explores increasingly deeper potential energy minima.
Admixture dynamics in Hispanics: A shift in the nuclear genetic ancestry of a South American population isolate
Authors: Bedoya Gabriel , Montoya Patricia , García Jenny , Soto Ivan , Bourgeois Stephane , Carvajal Luis , Labuda Damian , Alvarez Victor , Ospina Jorge , Hedrick Philip W. , Ruiz-Linares Andrés
Published: April 2006

Although it is well established that Hispanics generally have a mixed Native American, African, and European ancestry, the dynamics of admixture at the foundation of Hispanic populations is heterogeneous and poorly documented. Genetic analyses are potentially very informative for probing the early demographic history of these populations. Here we evaluate the genetic structure and admixture dynamics of a province in northwest Colombia (Antioquia), which prior analyses indicate was founded mostly by Spanish men and native women. We examined surname, Y chromosome, and mtDNA diversity in a geographically structured sample of the region and obtained admixture estimates with highly informative autosomal and X chromosome markers. We found evidence of reduced surname diversity and support for the introduction of several common surnames by single founders, consistent with the isolation of Antioquia after the colonial period. Y chromosome and mtDNA data indicate little population substructure among founder Antioquian municipalities. Interestingly, despite a nearly complete Native American mtDNA background, Antioquia has a markedly predominant European ancestry at the autosomal and X chromosome level, which suggests that, after foundation, continuing admixture with Spanish men (but not with native women) increased the European nuclear ancestry of Antioquia. This scenario is consistent with historical information and with results from population genetics theory.
Flexibly varying folding mechanism of a nearly symmetrical protein: B domain of protein A
Authors: Itoh Kazuhito , Sasai Masaki
Published: April 2006

The folding pathway of the B domain of protein A is the pathway most intensively studied by computer simulations. Recent systematic measurement of Φ values by Sato
et al.
[Sato, S., Religa, T. L., Daggett, V., & Fersht, A. R. (2004)
Proc. Natl. Acad. Sci. USA
101, 6952–6956], however, has shown that none of the published computational predictions is consistent with the detailed features of the experimentally observed folding mechanism. In this article we use a statistical mechanical model of folding to show that sensitive dependence of multiple transition state ensembles on temperature and the denaturant concentration is the key to resolving the inconsistency among simulations and the experiment. Such sensitivity in multiple transition state ensembles is a natural consequence of symmetry-breaking in a nearly symmetrical protein.
Proteasome inhibitors uncouple rhesus TRIM5α restriction of HIV-1 reverse transcription and infection
Authors: Wu Xiaolu , Anderson Jenny L. , Campbell Edward M. , Joseph Ajith M. , Hope Thomas J.
Published: April 2006

The primate TRIM5α proteins have recently been defined as cellular restriction factors, preventing primate infection by retroviruses from different species. For instance, rhesus TRIM5α (rhTRIM5α) restricts infection by HIV-1. Virtually all TRIM5α proteins block the early replication of retroviruses by preventing the accumulation of reverse transcription products, but the underlying mechanism remains unclear. In this article, we find that disrupting proteasome function alters rhTRIM5α localization and allows the normal generation of HIV-1 late reverse transcription products, even though HIV-1 infection and the generation of nuclear 1-LTR and 2-LTR viral cDNA forms remain impaired. This finding suggests rhTRIM5α restricts HIV infection in two distinct phases: (
i
) altering the normal passage of the reverse-transcribing viral genome to the nucleus and (
ii
) targeting the reverse transcription complex to be disrupted by the proteasome. Because proteasome inhibitor blocks the second phase, accumulation of a nonfunctional viral DNA genome can be readily observed. Defining each phase may reveal HIV-1 targets for future antiviral therapy in which dual blockade may be equally as effective as naturally occurring rhTRIM5α protein in preventing HIV-1 infection
in vivo
.
Functional differences between galactolipids and glucolipids revealed in photosynthesis of higher plants
Authors: Hölzl Georg , Witt Sandra , Kelly Amélie A. , Zähringer Ulrich , Warnecke Dirk , Dörmann Peter , Heinz Ernst
Published: April 2006

Galactolipids represent the most abundant lipid class in thylakoid membranes, where oxygenic photosynthesis is performed. The identification of galactolipids at specific sites within photosynthetic complexes by x-ray crystallography implies specific roles for galactolipids during photosynthetic electron transport. The preference for galactose and not for the more abundant sugar glucose in thylakoid lipids and their specific roles in photosynthesis are not understood. Introduction of a bacterial glucosyltransferase from
Chloroflexus aurantiacus
into the galactolipid-deficient
dgd1
mutant of
Arabidopsis thaliana
resulted in the accumulation of a glucose-containing lipid in the thylakoids. At the same time, the growth defect of the
dgd1
mutant was complemented. However, the degree of trimerization of light-harvesting complex II and the photosynthetic quantum yield of transformed
dgd1
plants were only partially restored. These results indicate that specific interactions of the galactolipid head group with photosynthetic protein complexes might explain the preference for galactose in thylakoid lipids of higher plants. Therefore, galactose in thylakoid lipids can be exchanged with glucose without severe effects on growth, but the presence of galactose is crucial to maintain maximal photosynthetic efficiency.
Nonconscious semantic processing of emotional words modulates conscious access
Authors: Gaillard Raphaël , Del Cul Antoine , Naccache Lionel , Vinckier Fabien , Cohen Laurent , Dehaene Stanislas
Published: April 2006

Whether masked words can be processed at a semantic level remains a controversial issue in cognitive psychology. Although recent behavioral studies have demonstrated masked semantic priming for number words, attempts to generalize this finding to other categories of words have failed. Here, as an alternative to subliminal priming, we introduce a sensitive behavioral method to detect nonconscious semantic processing of words. The logic of this method consists of presenting words close to the threshold for conscious perception and examining whether their semantic content modulates performance in objective and subjective tasks. Our results disclose two independent sources of modulation of the threshold for access to consciousness. First, prior conscious perception of words increases the detection rate of the same words when they are subsequently presented with stronger masking. Second, the threshold for conscious access is lower for emotional words than for neutral ones, even for words that have not been previously consciously perceived, thus implying that written words can receive nonconscious semantic processing.
Identification of S-nitrosylation motifs by site-specific mapping of the
S
-nitrosocysteine proteome in human vascular smooth muscle cells
Authors: Greco Todd M. , Hodara Roberto , Parastatidis Ioannis , Heijnen Harry F. G. , Dennehy Michelle K. , Liebler Daniel C. , Ischiropoulos Harry
Published: April 2006

S-nitrosylation, the selective modification of cysteine residues in proteins to form
S
-nitrosocysteine, is a major emerging mechanism by which nitric oxide acts as a signaling molecule. Even though nitric oxide is intimately involved in the regulation of vascular smooth muscle cell functions, the potential protein targets for nitric oxide modification as well as structural features that underlie the specificity of protein
S
-nitrosocysteine formation in these cells remain unknown. Therefore, we used a proteomic approach using selective peptide capturing and site-specific adduct mapping to identify the targets of S-nitrosylation in human aortic smooth muscle cells upon exposure to
S
-nitrosocysteine and propylamine propylamine NONOate. This strategy identified 20 unique
S
-nitrosocysteine-containing peptides belonging to 18 proteins including cytoskeletal proteins, chaperones, proteins of the translational machinery, vesicular transport, and signaling. Sequence analysis of the
S
-nitrosocysteine-containing peptides revealed the presence of acid/base motifs, as well as hydrophobic motifs surrounding the identified cysteine residues. High-resolution immunogold electron microscopy supported the cellular localization of several of these proteins. Interestingly, seven of the 18 proteins identified are localized within the ER/Golgi complex, suggesting a role for S-nitrosylation in membrane trafficking and ER stress response in vascular smooth muscle.
Evolution of a cytoplasmic tripartite motif (TRIM) protein in cows that restricts retroviral infection
Authors: Si Zhihai , Vandegraaff Nick , O’hUigin Colm , Song Byeongwoon , Yuan Wen , Xu Chen , Perron Michel , Li Xing , Marasco Wayne A. , Engelman Alan , Dean Michael , Sodroski Joseph
Published: April 2006

Primate tripartite motif 5α (TRIM5α) proteins mediate innate intracellular resistance to retroviruses. In humans,
TRIM5
is located in a paralogous cluster that includes
TRIM6
,
TRIM34
, and
TRIM22
. Although
TRIM6
and
TRIM34
orthologs are found in other mammals,
TRIM5
has to date been identified only in primates. Cow cells exhibit early blocks to infection by several retroviruses. We identify a cytoplasmic TRIM protein encoded by
LOC505265
that is responsible for the restriction of infection by several lentiviruses and N-tropic murine leukemia virus in cow cells. Susceptibility of N-tropic murine leukemia virus to 505265-mediated restriction is determined primarily by residue 110 of the viral capsid protein. Phylogenetically, cow
LOC505265
segregates with the
TRIM5
/
TRIM6
/
TRIM34
group, but is not an ortholog of known
TRIM
genes. The B30.2/SPRY domain of 505265 exhibits long variable regions, a characteristic of the proteins encoded by this paralogous group, and shows evidence of positive selection. Apparently, cows have independently evolved a retroviral restriction factor from the same TRIM family that spawned TRIM5 in primates. Particular features of this subset of cytoplasmic TRIM proteins may be conducive to the convergent evolution of virus-restricting factors.
Behavioral sensitization to amphetamine results from an uncoupling between noradrenergic and serotonergic neurons
Authors: Salomon Lucas , Lanteri Christophe , Glowinski Jacques , Tassin Jean-Pol
Published: April 2006

In rodents, drugs of abuse induce locomotor hyperactivity, and repeating injections enhances this response. This effect, called behavioral sensitization, persists many months after the last administration, thus mimicking long-term sensitivity to drugs observed in human addicts. We show here that, in naïve animals, noradrenergic and serotonergic systems, besides their behavioral activating effects, inhibit each other by means of the stimulation of α1b-adrenergic and 5-HT
2A
receptors and that this mutual inhibition vanishes with repeated injections of
d
-amphetamine; this uncoupling may be responsible for behavioral sensitization and for an increased reactivity of dopaminergic neurons. First, after repeated
d
-amphetamine injections, a
d
-amphetamine challenge induces a dramatic increase in cortical extracellular norepinephrine (NE) levels. This increased cortical NE release still occurs after 1 month of withdrawal but is diminished or blocked if sensitization is performed in the presence of prazosin, SR46349B, or both α1-adrenergic and 5-HT
2A
receptor antagonists, respectively. A strong correlation between increases in cortical extracellular NE levels and the expression of behavioral sensitization was found. Second, repeated
d
-amphetamine injections induce an increased reactivity of serotonergic neurons measured by cortical extracellular serotonin (5-HT) levels after the administration of a 5-HT releaser,
p
-chloroamphetamine. Third, knockout mice for α1b-adrenergic (α1b-AR KO) or 5-HT
2A
(5-HT
2A
-R KO) receptor, respectively, exhibit a behavioral and biochemical hyperreactivity to the acute injection of
p
-chloroamphetamine (α1b-AR KO; 5-HT levels) and
d
-amphetamine (5-HT
2A
-R KO; NE levels). Uncoupling between noradrenergic and serotonergic neurons may occur not only in addiction but also during chronic stressful situations, thus facilitating the onset of mental illness.
Bone-marrow-derived stem cells repair basement membrane collagen defects and reverse genetic kidney disease
Authors: Sugimoto Hikaru , Mundel Thomas M. , Sund Malin , Xie Liang , Cosgrove Dominic , Kalluri Raghu
Published: April 2006

Type IV collagen is a predominant component of basement membranes, and glomeruli of a kidney filter ≈70–90 liters of plasma every day through a specialized glomerular basement membrane (GBM). In Alport syndrome, a progressive disease primarily affecting kidneys, mutations in GBM-associated type IV collagen genes (COL4A3, COL4A4, or COL4A5) lead to basement membrane structural defects, proteinuria, renal failure, and an absence of all three GBM collagen triple helical chains because of obligatory posttranslational assembly requirements. Here, we demonstrate that transplantation of wild-type bone marrow (BM) into irradiated COL4A3
−/−
mice results in a possible recruitment of BM-derived progenitor cells as epithelial cells (podocytes) and mesangial cells within the damaged glomerulus, leading to a partial restoration of expression of the type IV collagen α3 chain with concomitant emergence of α4 and α5 chain expression, improved glomerular architecture associated with a significant reduction in proteinuria, and improvement in overall kidney histology compared with untreated COL4A3
−/−
mice or irradiated COL4A3
−/−
mice with BM from adult COL4A3
−/−
mice. The α3(IV) collagen produced by BM-derived podocytes integrates into the GBM and associates with other α-chains to form type IV collagen triple helical networks. This study demonstrates that BM-derived stem cells can offer a viable strategy for repairing basement membrane defects and conferring therapeutic benefit for patients with Alport syndrome.
Diffusion of isolated DNA molecules: Dependence on length and topology
Authors: Robertson Rae M. , Laib Stephan , Smith Douglas E.
Published: April 2006

The conformation and dynamics of circular polymers is a subject of considerable theoretical and experimental interest. DNA is an important example because it occurs naturally in different topological states, including linear, relaxed circular, and supercoiled circular forms. A fundamental question is how the diffusion coefficients of isolated polymers scale with molecular length and how they vary for different topologies. Here, diffusion coefficients
D
for relaxed circular, supercoiled, and linear DNA molecules of length
L
ranging from ≈6 to 290 kbp were measured by tracking the Brownian motion of single molecules. A topology-independent scaling law
D
∼
L
−ν
was observed with ν
L
= 0.571 ± 0.014, ν
C
= 0.589 ± 0.018, and ν
S
= 0.571 ± 0.057 for linear, relaxed circular, and supercoiled DNA, respectively, in good agreement with the scaling exponent of ν ≅ 0.588 predicted by renormalization group theory for polymers with significant excluded volume interactions. Our findings thus provide evidence in support of several theories that predict an effective diameter of DNA much greater than the Debye screening length. In addition, the measured ratio
D
Circular
/
D
Linear
= 1.32 ± 0.014 was closer to the value of 1.45 predicted by using renormalization group theory than the value of 1.18 predicted by classical Kirkwood hydrodynamic theory and agreed well with a value of 1.31 predicted when incorporating a recently proposed expression for the radius of gyration of circular polymers into the Zimm model.
Deficiency of the zinc finger protein ZPR1 causes neurodegeneration
Authors: Doran Beth , Gherbesi Norberto , Hendricks Gregory , Flavell Richard A. , Davis Roger J. , Gangwani Laxman
Published: April 2006

Mutations that cause reduced expression of the full-length Survival Motor Neurons (SMN) protein are a major cause of spinal muscular atrophy (SMA), a disease characterized by degeneration of the α-motor neurons in the anterior horn of the spinal cord. The severity of SMA may be influenced by the actions of modifier genes. One potential modifier gene is represented by
ZPR1
, which is down-regulated in patients with SMA and encodes a zinc finger protein that interacts with complexes formed by SMN. To test the functional significance of
ZPR1
gene down-regulation, we examined a mouse model with targeted ablation of the
Zpr1
gene. We report that ZPR1-deficient mice exhibit axonal pathology and neurodegeneration. These data identify ZPR1 deficiency as a contributing factor in neurodegenerative disorders.