bluuebunny/crossref_metadata_2025 huggingface dataset:
Processing of a Strong Biodegradable Poly[(R)‐3‐hydroxybutyrate] Fiber and a New Fiber Structure Revealed by Micro‐Beam X‐Ray Diffraction with Synchrotron Radiation
Authors: Iwata Tadahisa , Aoyagi Yoshihiro , Fujita Masahiro , Yamane Hideki , Doi Yoshiharu , Suzuki Yoshio , Takeuchi Akihisa , Uesugi Kentaro
Published: May 2004

Summary: Biodegradable poly[(R)‐3‐hydroxybutyrate] (P(3HB)) fibers with high tensile strength of 1.32 GPa were processed from ultra‐high‐molecular‐weight P(3HB) by a method combining cold‐drawing and two‐step‐drawing procedures at room temperature. The distribution of molecular structures in a mono‐filament was analyzed by micro‐beam X‐ray diffraction with synchrotron radiation. It was revealed that the P(3HB) fiber has a new core‐sheath structure consistent with two types of molecular conformations: a 21 helix conformation in the sheath region and a planar zigzag conformation in the core region.

P(3HB) fiber processed by cold‐drawing in ice water and two‐step drawing at room temperature, and subsequently annealing at 50 °C.

image

P(3HB) fiber processed by cold‐drawing in ice water and two‐step drawing at room temperature, and subsequently annealing at 50 °C.
Use of Cartesian Rotation Vectors in Brownian Dynamics Algorithms: Theory and Simulation Results
Authors: Naess Stine Nalum , Elgsaeter Arnljot
Published: May 2004

Summary: We have shown that the components of Cartesian rotation vectors can be used successfully as generalized coordinates describing angular orientation in Brownian dynamics simulations of non‐spherical nanoparticles. For this particular choice of generalized coordinates, we rigorously derived the conformation‐space diffusion equations from kinetic theory for both free nanoparticles and nanoparticles interconnected by springs or holonomic constraints into polymer chains. The equivalent stochastic differential equations were used as a foundation for the Brownian dynamics algorithms. These new algorithms contain singularities only for points in the conformation‐space where both the probability density and its first coordinate derivative equal zero (weak singularities). In addition, the coordinate values after a single Brownian dynamics time step are throughout the conformation‐space equal to the old coordinate values plus the respective increments. For some parts of the conformation‐space these features represent a major improvement compared to the situation when Eulerian angles describe rotational dynamics. The presented simulation results of the equilibrium probability density for free nanoparticles are in perfect agreement with the results from kinetic theory.

Simulation of p(eq)(Φ) for free nanoparticles.

image

Simulation of p(eq)(Φ) for free nanoparticles.
Electrochemical behaviour of Mo‐containing austenitic stainless steels in buffer solution
Authors: El‐Taib Heakal F. , Ameer M.A. , El‐Aziz A.M. , Fekry A.M.
Published: June 2004

The effect of pH on the electrochemical behavior of austenitic stainless steels in naturally aerated and nitrogen‐deaerated buffer solutions has been studied.

Potentiodynamic and ac impedance techniques were used. The results indicate that corrosion current (Icorr) decreases with pH. By examining the impedance data for the seven tested steels under various conditions, it seems that the total resistance (RT) value is a suitable indication parameter for explaining the role of molybdenum and the other supplementary alloying additions (Ni, N, Cu and Mn) on the passive film behaviors as a function of pH of the forming solutions. As a general trend, the RT values for all steels tended to be lower in the basic buffer than in the acidic solutions.
Expression profile of eukaryotic translation factors in human cancer tissues and cell lines
Authors: Joseph Pius , O'Kernick Christina M. , Othumpangat Sreekumar , Lei Yi‐Xiong , Yuan Bao‐Zhu , Ong Tong‐Man
Published: May 2004

Several studies have demonstrated the overexpression of certain eukaryotic translation factors in human cancer cell lines and in malignant tissues. In this study, with human cancer cell lines derived from lungs, breast, prostate, and skin, we have examined the expression profile of 36 translation factors consisting of 27 initiation factors, 8 elongation factors, and 1 termination factor. Translation initiation factors 2C2 and 4E1 and translation elongation factors 1A2 and 1δ were found overexpressed (2‐ to 2000‐fold) in many of the cancer cell lines compared to their corresponding normal cell lines. Among the translation factors analyzed, translation elongation factor 1A2 exhibited the most significant alteration in expression: 10‐ to 2000‐fold overexpression was noticed in nine out of ten cancer cell lines analyzed. Whether the overexpression of translation elongation factor 1A2 can be used as a potential tumor marker was tested with the cancer profiling array (BD Biosciences, Palo Alto, CA) consisting of 241 paired cDNA samples generated from 13 different cancer/noncancer tissue types. Overexpression of translation elongation factor 1A2 was noticed in several tumor tissue samples, most notably in the human colon cancer samples which exhibited at least a twofold overexpression among 35% of the samples analyzed. Besides colon, tumor samples derived from lungs, kidney, rectum, and ovary also exhibited more than a twofold overexpression of translation elongation factor 1A2 in at least 20% of the samples analyzed. These results indicate that human carcinogenesis is often associated with alterations in the expression of various translation factors especially the overexpression of eukaryotic translation elongation factor 1A2. © 2004 Wiley‐Liss, Inc.
Nkx2.1 transcription factor in lung cells and a transforming growth factor‐β1 heterozygous mouse model of lung carcinogenesis
Authors: Kang Yang , Hebron Haroun , Ozbun Laurent , Mariano Jennifer , Minoo Parviz , Jakowlew Sonia B.
Published: May 2004

The Nkx2.1 homeobox gene and transforming growth factor‐β1 (TGF‐β1) are essential for organogenesis and differentiation of the mouse lung. NKX2.1 is a marker of human lung carcinomas, but it is not known whether this gene participates in early tumorigenesis. Addition of TGF‐β1 to TGF‐β1‐responsive nontumorigenic mouse lung cells cotransfected with a NKX2.1Luc luciferase reporter and either a Sp1 or Sp3 plasmid showed a significant increase or decrease, respectively, in NKX2.1Luc transcription. Cotransfection of Sp3 and dominant‐negative TGF‐β type II receptor plasmids negated the effect of Sp1. Cotransfected Sp1 plasmid with either dominant‐negative Smad2 or Smad3 or Smad4 plasmids significantly decreased NKX2.1Luc transcription. Electrophoretic mobility shift assays revealed binding of Sp1 and Smad4 to the NKX2.1 promoter. With a TGF‐β1 heterozygous mouse model, Nkx2.1 mRNA and protein in lungs of TGF‐β1 heterozygous mice were significantly lower compared to wildtype (WT) littermates. Competitive reverse transcription (RT)‐polymerase chain reaction (PCR) and immunostaining showed that Nkx2.1 mRNA and protein decreased significantly in adenomas and adenocarcinomas compared to normal lung tissue. Our in vitro data showed that regulation of Nkx2.1 by TGF‐β1 occurs through TGF‐β type II receptor and Smad signaling, with Sp1 and Sp3 in lung cells. Our in vivo data showed reduced Nkx2.1 in lungs of TGF‐β1 heterozygous mice compared to WT mice, that is detectable in adenomas, and that is further reduced in carcinogenesis, and that correlates with reduction of Sp1, Sp3, and Smads in lung adenocarcinomas. Our findings suggest that reduced Nkx2.1 and TGF‐β1 signaling components may contribute to tumorigenesis in the lungs of TGF‐β1 heterozygous mice. Published 2004 Wiley‐Liss, Inc.
Cannabis‐induced propriospinal myoclonus
Authors: Lozsadi Dora A. , Forster Alan , Fletcher Nicholas A.
Published: June 2004

We report on a case of a 25‐year‐old woman with clusters of myoclonus induced by a single exposure to inhaled cannabis. Investigations excluded a structural abnormality of the spine. Multi‐channel surface EMG with parallel frontal EEG recording confirmed the diagnosis of propriospinal myoclonus. © 2004 Movement Disorder Society
Bionanotechnology based on silica nanoparticles
Authors: Tan Weihong , Wang Kemin , He Xiaoxiao , Zhao Xiaojun Julia , Drake Timothy , Wang Lin , Bagwe Rahul P.
Published: May 2004

We have developed uniform core/shell nanoparticles, consisting of a silica layer coating and pigments or magnetite core, using a water‐in‐oil microemulsion method. The nanoparticles are highly luminescent and photostable with the size ranging from 5 nm to 400 nm. Bioconjugation of these silica nanoparticles adds unique biofunctions with various molecules such as enzymes, antibodies, and DNA molecules. Significant advantages have been shown in using bioconjugated nanoparticles for biosensing and bioimaging, such as cell staining, DNA detection and separation, rapid single bacterium detection, and biotechnological application in DNA protection. © 2004 Wiley Periodicals, Inc. Med Res Rev, 24, No. 5, 621–638, 2004
AMPA receptor ligands: Synthetic and pharmacological studies of polyamines and polyamine toxins
Authors: Strømgaard Kristian , Mellor Ian
Published: May 2004

α‐Amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole propionic acid (AMPA) receptors (AMPAR), subtype of the ionotropic glutamate receptors (IGRs), mediate fast synaptic transmission in the central nervous system (CNS), and are involved in many neurological disorders, as well as being a key player in the formation of memory. Hence, ligands affecting AMPARs are highly important for the study of the structure and function of this receptor, and in this regard polyamine‐based ligands, particularly polyamine toxins, are unique as they selectively block Ca2+‐permeable AMPARs. Indeed, endogenous intracellular polyamines are known to modulate the function of these receptors in vivo. In this study, recent developments in the medicinal chemistry of polyamine‐based ligands are given, particularly focusing on the use of solid‐phase synthesis (SPS) as a tool for the facile generation of libraries of polyamine toxin analogues. Moreover, the recent development of highly potent and very selective AMPAR ligands is described. Additionally, we provide a detailed account on the mechanism and site of action of AMPAR blockade by polyamine‐based ligands, including examples of how these ligands are used as tools to study AMPAR, and a comparison with their action on other ionotropic receptors. © 2004 Wiley Periodicals, Inc. Med Res Rev, 24, No. 5, 589–620, 2004
2‐Octylcynanoacrylate‐assisted microvascular anastomosis in a rat model: Long‐term biomechanical properties and histological changes
Authors: Ong Yee Siang , Yap Karen , Ang Erik S.W. , Tan Kok Chai , Ng Robert T.H. , Song Irene C.
Published: June 2004

The aim of this study was to establish the long‐term biomechanical and histological properties of 2‐octylcyanoacrylate‐assisted microvascular anastomosis over conventional suture‐only anastomosis in the laboratory rat model. The biomechanical and histological properties of three groups of vessels were compared: 1) vessels with 2‐octylcyanoacrylate‐assisted anastomoses (study group); 2) vessels with suture‐only anastomoses (control group); and 3) normal unoperated vessels (sham group). In total, 144 adult rats were used, and these were studied at 1 week, 1 month, 3 months, and 6 months postanastomosis. At 6 months, the tensile strength of study vessels was significantly higher than control vessels. The stiffness of study and control vessels was similar at all time intervals. Histologically, there was no evidence that 2‐ octylcyanoacrylate caused toxicity to vessel walls, and there was less perivasacular foreign‐body giant‐cell reaction in the study group compared to the control group. Long‐term follow‐up showed that microvascular anastomosis with 2‐octylcyanoacrylate in rat femoral arteries had superior tensile strength and similar stiffness to vessels anastomosed with sutures only, without adverse effects to surrounding tissues. © 2004 Wiley‐Liss, Inc.
Block copolymerizations of higher 1‐olefins with traditional polar monomers using metallocene‐type single component lanthanide initiators
Authors: Yasuda Hajime , Desurmont Guillaume
Published: May 2004

Block copolymerizations of 1‐pentene or 1‐hexene with methyl methacrylate or ε‐caprolactone were explored using [Me2Si(2‐SiMe3‐4‐t‐BuMe2SiC5H2)2YH]2 (1) or [Me2Si(2‐SiMe3‐4‐t‐BuC5H2)2SmH]2 (2) as an initiator in toluene or in neat mixtures by the successive additions of monomers in this order. Random copolymerizations of 1‐pentene with 1‐hexene, and random copolymerization of ethylene with 1‐hexene were also performed using 1 as an initiator. Copyright © 2004 Society of Chemical Industry
Orientation effects on the deformation and fracture properties of high‐density polyethylene/ethylene vinyl acetate (HDPE/EVA) blends
Authors: Na Bing , Zhang Qin , Wang Yong , Fu Qiang
Published: May 2004

In this paper, the tensile deformation and fracture toughness of high‐density polyethylene (HDPE)/ethylene vinyl acetate (EVA) blends, obtained by dynamic packing injection moulding, have been comprehensively investigated in different directions of rectangle samples, including longitudinal, latitudinal and oblique directions relative to the flow direction. Two kinds of EVA were used with VA content 16 wt% (16EVA) and 33 wt% (33EVA) to control the interfacial interactions. The results indicate that molecular orientation and interfacial interaction play very important roles to determine the tensile behaviour and fracture toughness. Biaxial‐reinforcement of tensile strength was seen for HDPE/16EVA blends but only uniaxial‐reinforcement was observed for HDPE/33EVA blends. The difference is caused by the different interfacial interactions as highlighted by the peel test, scanning electron microscopy (SEM) observation as well as theoretical evaluation. Very high impact strength, decreasing with increasing EVA content, was observed when the fracture propagation is perpendicular to the shear flow direction, while a low impact strength, increasing slightly increasing with EVA content, was seen when the fracture propagation is parallel to the shear flow. The fracture of oblique samples is always along the flow direction instead of along the impact direction or tensile direction. The tensile behaviour and fracture toughness are discussed on the basis of the formation of transcrystalline zones, orientation of EVA particles and matrix toughness of HDPE in different directions. Copyright © 2004 Society of Chemical Industry
Crystallization and melting behaviour of polypropylene ‘catalloys’
Authors: Zheng Qiang , Lin Zhonghua , Peng Mao
Published: May 2004

The crystallization and melting behaviour of polypropylene ‘catalloys’ (PP‐cats) as well as pure polypropylene (PP) were investigated using differential scanning calorimetry. The results showed that, for PP‐cats and PP, a single melting peak of PP appeared under slow cooling rate. When the cooling rate is fast enough in the non‐isothermal case, or the crystallization temperature is relatively high in the isothermal case, a shoulder peak appears in front of the melting peak with increasing ethylene content in PP‐cats. It is believed that this shoulder is induced by recrystallization of crystals initially formed during non‐isothermal or isothermal crystallization. When the ethylene component in PP‐cats reached a certain level, there existed a melting peak of polyethylene (PE) crystallized during the cooling process. Polarized optical microscopy (POM) showed that the spherulites formed by PP‐cats were much smaller and had less perfect morphology compared with that formed by pure PP at the same cooling rate. And with the increase of the cooling rate, the spherulites could not be clearly observed. Copyright © 2004 Society of Chemical Industry
An investigation into the degree and rate of polymerization of poly(methyl methacrylate) in the ionic liquid 1‐butyl‐3‐methylimidazolium hexafluorophosphate
Authors: Benton Michael G , Brazel Christopher S
Published: May 2004

Room‐temperature ionic liquids (ILs), including 1‐butyl‐3‐methylimidazolium hexafluorophosphate, [bmim+][PF6−], were investigated as replacements for volatile organic compounds in the free‐radical solution polymerization of poly(methyl methacrylate) (PMMA). The latter was synthesized in benzene and [bmim+][PF6−] at 70 °C via a free‐radical process and the degree and rate of polymerization were compared based on the solvent used. The degree of polymerization was found to be five times higher in [bmim+][PF6−] than in benzene, while the rate of reaction was approximately four times faster in [bmim+][PF6−]. The results indicate the potential for using ILs to produce high‐molecular‐weight polymers and block structures based on the increased free‐radical stability in ILs. Copyright © 2004 Society of Chemical Industry
Crystallization behavior of syndiotactic and atactic 1,2‐polybutadiene blends
Authors: Cai Jiali , Han Ying , Yuan Zuanru , Cheng Rongshi , Wang Zhiliu , Jiang Liansheng , Bi Jifu , Li Genxi
Published: May 2004

Two 1,2‐polybutadiene samples, ie syndiotactic 1,2‐polybutadiene (sPB) and atactic 1,2‐polybutadiene (aPB), were synthesized by using the same Iron(III) catalyst system, although with changing contents of the third catalyst component. Effects of the composition of aPB on the crystallization behavior of sPB have been characterized by wide‐angle X‐ray diffraction (WAXD) and differential scanning calorimetry (DSC). Analysis of the results indicates that the intensity of the (010) peak of sPB is influenced much more easily than that of the (200)/(110) peak by the amorphous aPB sample, but the structure of sPB does not change with the changing composition of sPB. aPB is thermodynamically miscible with sPB in the melt, and retards the melt crystallization of sPB. At the same time, non‐isothermal crystallization kinetic studies of neat sPB and 1/2.5 blends were carried out by DSC. The Avrami equations modified by Jeziorny and Privalko, were used to fit the primary stage of the non‐isothermal crystallizations of neat sPB and the 1/2.5 blends. A larger Avrami exponent for neat sPB than for the blends was observed, and possible reasons are discussed. The activation energies (ΔE) were determined to be −88 and −106 kJ mol−1 by the isoconversional Friedman method for neat sPB and sPB in the blends, respectively. Copyright © 2004 Society of Chemical Industry
A prostate stem cell antigen‐derived peptide immunogenic in HLA‐A24− prostate cancer patients
Authors: Matsueda Satoko , Yao Akihisa , Ishihara Yuki , Ogata Rika , Noguchi Masanori , Itoh Kyogo , Harada Mamoru
Published: May 2004

BACKGROUND

We attempted to identify prostate stem cell antigen (PSCA)‐derived peptides immunogenic in HLA‐A24+ prostate cancer patients.

METHODS

Peripheral blood mononuclear cells (PBMCs) were stimulated in vitro with each of three different PSCA‐derived peptides, which were prepared based on the HLA‐A24 binding motif, and their peptide‐specific and HLA‐A24‐restricted anti‐tumor responses were examined. Plasma levels of immunoglobulin G (IgG) against PSCA peptides were measured by enzyme‐linked immunosorbent assay (ELISA).

RESULTS

Among three PSCA peptides, the PSCA 76–84 peptide most effectively induced peptide‐specific cytotoxic T lymphocytes (CTLs) from PBMCs of HLA‐A24+ prostate cancer patients. Cytotoxicity was dependent on peptide‐specific and CD8+ T cells. The PSCA 76–84 peptide‐stimulated PBMCs showed a significant level of cytotoxicity against prostate cancer cells in an HLA‐A24‐restricted manner. IgG reactive to the PSCA 76–84 peptide was detected in half of patients.

CONCLUSIONS

The PSCA 76–84 peptide should be considered for use in clinical trials of immunotherapy for HLA‐A24+ patients. © 2004 Wiley‐Liss, Inc.
Molecular alterations associated with LNCaP cell progression to androgen independence
Authors: Shi Xu‐Bao , Ma Ai‐Hong , Tepper Clifford G. , Xia Liang , Gregg Jeffrey P. , Gandour‐Edwards Regina , Mack Philip C. , Kung Hsing‐Jien , deVere White Ralph W.
Published: May 2004

BACKGROUND

There is no effective therapy currently available for androgen‐independent (AI) prostate cancer (CaP). This is largely due to lack of information about the molecular mechanisms by which androgen‐dependent tumor cells progress to androgen independence. In this study, we investigated molecular alterations occurring in AI LNCaP cells.

METHODS

We established and characterized three AI LNCaP sublines that exhibited a wide range of cytogenetic alterations. In order to understand why androgen‐sensitive LNCaP cells can survive in an androgen‐deprived environment, we analyzed the expression of signaling proteins associated with proliferation and survival of AI cells. In addition, gene expression profiling was performed to gain insight into molecular alterations in these LNCaP sublines.

RESULTS

These LNCaP sublines exhibited heightened levels of androgen receptor (AR), HER2, MAPK, serine 473‐phosphorylated Akt, and Bcl‐2, implicating these proteins as mediators of AI growth. Gene expression profiling identified a common set of 66 genes that were differentially expressed in all three sublines compared to the parental LNCaP cells. Of these, 32 were apparently androgen regulated, while the remainder comprised an expression signature specific for androgen independence.

CONCLUSION

We have developed AI LNCaP cell models and identified several genes that are specifically expressed in these models. Elucidating the relative importance of these genetic changes will help define the molecular mechanism by which CaP progresses to androgen independence. © 2004 Wiley‐Liss, Inc.
Immunotherapy (APC8015, Provenge®) targeting prostatic acid phosphatase can induce durable remission of metastatic androgen‐independent prostate cancer: A phase 2 trial
Authors: Burch Patrick A. , Croghan Gary A. , Gastineau Dennis A. , Jones Lori A. , Kaur Judith S. , Kylstra Jelle W. , Richardson Ronald L. , Valone Frank H. , Vuk‐Pavlović Stanimir
Published: May 2004

BACKGROUND

Prostate cancer is the most commonly diagnosed malignancy in American men, yet treatment of its metastatic androgen‐independent form remains inadequate. This mandates development of new therapies such as immunotherapy. In this Phase 2 trial, we determined the efficacy of antigen presenting cells (APCs) loaded with PA2024, a recombinant fusion protein containing prostatic acid phosphatase (PAP) and GM‐CSF.

METHODS

We enrolled 21 patients with histologically documented androgen‐independent prostate carcinoma that could be evaluated by radionuclide bone scan or computed tomography scan. APC8015 was prepared from a leukapheresis product; it contained autologous CD54‐positive PA2024‐loaded APCs with admixtures of monocytes, macrophages, B and T cells. APC8015 was infused intravenously twice, 2 weeks apart. Two weeks after the second infusion, patients received three subcutaneous injections of 1.0 mg of PA2024 1 month apart. We monitored patients' physical condition, immune response, and laboratory parameters.

RESULTS

Nineteen patients could be evaluated for response to treatment. The median time to progression was 118 days. Treatment was tolerated reasonably well; most adverse effects were secondary to APC8015 and were NCI Common Toxicity Criteria Grade 1–2. Four of the 21 patients reported Grade 3–4 adverse events. Two patients exhibited a transient 25–50% decrease in prostate‐specific antigen (PSA). For a third patient, PSA dropped from 221 ng/ml at baseline to undetectable levels by week 24 and has remained so for more than 4 years. In addition, this patient's metastatic retroperitoneal and pelvic adenopathy has resolved. PBMC collected from patients for at least 16 weeks proliferated upon in vitro stimulation by PA2024. For the patient with responsive disease, PBMC could be stimulated for 96 weeks.

CONCLUSIONS

This study demonstrates a definite clinical response of androgen‐independent prostate cancer to APC immunotherapy. Currently we are studying this mode of therapy in Phase 3 trials. © 2004 Wiley‐Liss, Inc.
Antisense MDM2 oligonucleotides restore the apoptotic response of prostate cancer cells to androgen deprivation
Authors: Mu Zhaomei , Hachem Paul , Agrawal Sudhir , Pollack Alan
Published: May 2004

BACKGROUND

Early in the malignant transformation of prostate epithelial cells, the apoptotic response to androgen deprivation (AD) is lost and the principle response is a slowing of cell growth. In this study, we tested whether interruption of MDM2 function using antisense MDM2 oligonucleotide (AS) affects the apoptotic response of prostate cancer cells to AD.

METHODS

Wild type LNCaP cells and MDM2‐overexpressing (LNCaP‐MST) cells were treated with AS alone or in combination with AD. Protein levels of MDM2, p53, and p21 were determined by Western blotting. Cell viability was measure by trypan blue staining. Apoptotic cell death was confirmed by cell morphological changes, annexin V/propidium iodide staining and caspase‐3 + 7 activity. Overall cell survival was quantified by clonogenic assay.

RESULTS

AS inhibited MDM2 expression to a greater extent in LNCaP cells, as compared to LNCaP‐MST cells. AS enhanced the expression of p53 and p21 in both cell lines. The growth inhibitory and cell death effects of AS + AD were generally greater than AS alone in LNCaP cells. Treatment of LNCaP cells with AS + AD for 72 hr caused a significant increase in cell death (66%) over AD alone (13%), AS alone (33%), or AD + AS + R1881 (34% with synthetic androgen replacement) that was attributable mainly to apoptosis. Clonogenic survival reflected the same pattern.

CONCLUSIONS

Our results suggest that the apoptotic response of prostate cancer to AD is strongly influenced by MDM2 expression. Antisense MDM2 has broad potential as a therapeutic agent to sensitize prostate cancer cells to AD therapy by enhancing apoptotic cell death. © 2004 Wiley‐Liss, Inc.
Polo‐like kinase 1 is overexpressed in prostate cancer and linked to higher tumor grades
Authors: Weichert Wilko , Schmidt Mathias , Gekeler Volker , Denkert Carsten , Stephan Carsten , Jung Klaus , Loening Stefan , Dietel Manfred , Kristiansen Glen
Published: May 2004

BACKGROUND

Polo‐like kinase 1 (PLK1) is known to be one of the key players in the regulation of mitosis of both normal and malignant transformed cells. Moreover, several studies reported an overexpression of PLK1 in human malignancies compared to the corresponding tissue of origin.

METHODS

In this study, expression of PLK1 was investigated by immunohistochemistry in 78 tissue specimens of prostate carcinoma and in adjacent normal prostate tissue as well as in benign prostate hyperplasia. PLK1 expression was semiquantitavely scored and subsequently correlated to clinicopathological parameters and patient prognosis.

RESULTS

No significant PLK1 expression was observed in normal prostate glandular epithelium and stroma. Specimens of benign prostate hyperplasia were PLK1‐negative as well. In contrast, 52.6% of all prostate carcinomas showed strong expression of PLK1. High grade intraepithelial lesions, if present, stained almost invariably in the same manner as the respective invasive tumors. Expression of PLK1 correlated positively with Gleason grade (P = 0.011). No other significant correlations of PLK1 expression with either tumor stage, WHO tumor grade, preoperative PSA, age, or resection margins could be established. In an analysis for differences in PSA‐relapse‐free survival time, PLK1 expression was not a prognostic marker.

CONCLUSIONS

These results demonstrate a high rate of PLK1‐positivity in prostate cancer which suggests involvement of PLK1 in tumorigenesis and progression in this tumor entity. Therefore, targeted strategies focussing on PLK1 inhibition might represent a promising new chemotherapeutic approach in prostate cancer. © 2004 Wiley‐Liss, Inc.
Characterization and comparative analyses of transcriptomes from the normal and neoplastic human prostate
Authors: Clegg Nigel , Abbott Denise , Ferguson Camari , Coleman Roger , Nelson Peter S.
Published: May 2004

BACKGROUND

The prostate gland is a highly specialized organ with functional attributes that serve to enhance the fertility of mammalian species. Pathological processes affecting the prostate include benign prostate hypertrophy and prostate carcinoma; diseases that account for major morbidity and mortality in middle‐aged and elderly men. To facilitate studies of biological processes uniquely represented in the prostate and assess molecular alterations associated with prostate carcinoma, we sought to establish the diversity of gene expression in the normal and neoplastic prostate through the compilation and analysis of a prostate transcriptome.

METHODS

We assembled and annotated ESTs derived from prostate cDNA libraries that were either produced in our laboratory or available from public sequence repositories such as CGAP, dbEST, and Unigene. Determinations of differential gene expression between the normal prostate, other normal tissues, and neoplastic prostate tissues was performed using statistical algorithms. Confirmation of differential expression was performed by quantitative PCR and Northern analysis.

RESULTS

A total of 99,448 high‐quality ESTs were assembled and annotated to produce a prostate transcriptome comprised of 24,580 distinct TUs. Comparative analyses of gene expression levels identified 61 TUs with exclusive expression in the prostate and 45 TUs with high levels of expression in the prostate relative to at least 25 other normal tissues (P > 0.99). Comparative analyses of ESTs derived from neoplastic prostate tissues identified 75 genes with dysregulated expression in cancer (P > 0.99).

CONCLUSIONS

The human prostate expresses a diverse repertoire of genes that reflect a functionally complex organ. The identification of genes with prostate‐restricted or enhanced expression may provide additional insights into the biochemical processes that interact to form the developmental, signaling, and metabolic pathways of the normal and neoplastic gland. © 2004 Wiley‐Liss, Inc.
Geometric phase effect at N‐fold electronic degeneracies in Jahn–Teller systems
Authors: Varandas A. J. C. , Xu Z. R.
Published: June 2004

The geometric phase effect at arbitrary integral N‐fold electronic degeneracies is investigated in Jahn–Teller systems. It is shown to be a property inherent to inversion of the adiabatic electronic wave vectors in the N‐dimensional electronic wave‐vector space. The relationship between the geometric phase and mixing angles has also been established. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Theoretical study of the double bond migration mechanism with participation of hydroxide ion
Authors: Kobychev Vladimir B. , Vitkovskaya Nadezhda M. , Trofimov Boris A.
Published: June 2004

The prototropic isomerization of the propene molecule in the presence of hydroxide ion was studied using ab initio Hartree–Fock and Møller–Plesset second‐order perturbation theory (MP2) approaches, as well as the density functional theory, in a gas‐phase and dimethyl sulfoxide solution. The results obtained within Born and Onsager models as well as the self‐consistent isodensity (SCIPCM) and the integral equation formalism (IEFPCM) versions of the polarizable continuum model suppose the proton migration mechanism involving formation of the intermediate complex of the allyl anion with a water molecule. This mechanism looks preferable compared with the traditional two‐stage one, even in the case of methylthiopropene molelcule, which forms a markedly more stable carbanion. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Long‐term depression in horizontal slices of the rat lateral amygdala
Authors: Kaschel Tobias , Schubert Manja , Albrecht Doris
Published: May 2004

Long‐term depression (LTD) is an enduring decrease in synaptic efficacy and is thought to underlie memory. In contrast to investigations of plasticity mechanisms in the amygdala in rat coronal slices, this study was done in horizontal slices. Field excitatory postsynaptic potentials (fEPSPs) and EPSPs, respectively, were recorded extracellularly and intracellularly from the lateral nucleus of the amygdala (LA). We show that low‐frequency stimulation (LFS) induces LTD in the LA, when stimulation electrodes were located in the LA. No significant differences were found between females and males. In dependence of strain variations, a reduction of GABAergic inhibition either reduced the magnitude of LTD or was a prerequisite for the induction of extracellularly recorded LA‐LTD. Theta pulse stimulation (TPS) of afferents within the LA caused a weaker LTD than LFS. Theta burst stimulation (TBS) given 20 min after the end of LFS reversed LTD, whereas high‐frequency stimulation (HFS) resulted in long‐term potentiation (LTP) that was significantly stronger than that obtained in naive slices. Therefore, primed induction of LTD facilitates high‐frequency‐induced LTP in the rat lateral amygdala. NMDARs as well as group II mGluRs were involved in the mediation of LA‐LTD. In contrast to data obtained by stimulation of afferents running within the LA, LFS of the external capsule fibers induced a weak LA‐LTD, and TPS was not able to induce LTD. This study showed for the first time that LTD can be induced in the LA by standard LFS (900 pulses at 1 Hz) and that LTP stimuli reversed LTD. The results also provide further evidence for the broad sensitivity of synaptic plasticity mechanisms to the history of prior activity. Synapse 53:141–150, 2004. © 2004 Wiley‐Liss, Inc.
Immunolocalization of CB1 receptor in rat striatal neurons: A confocal microscopy study
Authors: Fusco F.R. , Martorana A. , Giampà C. , De March Z. , Farini D. , D'Angelo V. , Sancesario G. , Bernardi G.
Published: June 2004

Several lines of evidence indicate that cannabinoids, among other functions, are involved in motor control. Although cannabinoid receptors (CB1) mRNA has been observed in medium‐sized spiny neurons of the striatum, a description of the precise localization of CB1 at a protein level among striatal cells is still lacking. Therefore, we performed immunohistochemical studies with light and confocal microscopy to identify neuronal subpopulations that express CB1 and to assess the distribution of the receptor within these neurons. In our single label light microscopy study, CB1 was observed in most medium‐sized neurons of the caudate‐putamen. However, CB1 was also present in large‐sized neurons scattered throughout the striatum. Our dual‐label study showed that 89.3% of projection neurons in matrix contain CB1, and that 56.4% of projection neurons in patch are labeled for CB1. To investigate the presence of CB1 among the different subclasses of striatal interneurons we performed a double‐labeling study matching CB1 and each of the striatal interneuron markers, namely, choline acetyl‐transferase, parvalbumin, calretinin, and nitric oxide synthase. Our double‐label study showed that most parvalbumin immunoreactive interneurons (86.5%), more than one‐third (39.2%) of cholinergic interneurons, and about one‐third (30.4%) of the NOS‐positive neurons are labeled for CB1. Calretinin‐immunolabeled neurons were devoid of CB1. Synapse 53:159–167, 2004. © 2004 Wiley‐Liss, Inc.
How a new realistic mobility model can affect the relative performance of a mobile networking scheme
Authors: Tugcu Tuna , Ersoy Cem
Published: June 2004

The validity of the mobility model used to evaluate a cellular network determines the validity of the evaluation. In the literature, unrealistic assumptions on mobility are exercised for the sake of simplicity. In this paper, we present a novel mobility model which is realistic in the sense that it captures themoving‐in‐groups,conscious travelingandinertialbehaviours of the subscribers while respecting thenon‐pass‐throughfeature of structures like households and preserving the autonomy of the subscribers. The mobility and call patterns of the subscribers are determined according to the locus of the subscriber over a real map. Thus, our model allows the subscribers to leave home or arrive home, walk or drive in the streets, get on the highways at specific entry points together with numerous hot and blind spots in the terrain, like city centers and lakes. The call pattern of a subscriber is affected by the type of structure he is in. The model can work on real maps to simulate the mobility patterns in real life. We have evaluated the proposed model against the well‐known way point mobility model. We also analyzed the effect of the mobility model on systems with and without guard channels. Copyright © 2004 John Wiley & Sons, Ltd.
Designing a wireless network with directional antennas: frequency division issue
Authors: Wu Yiwen , Hui Joseph
Published: June 2004

We design a mobile ad‐hoc network (MANET), where nodes are equipped with several multi‐beam adaptive array (MBAA) systems. Such devices provide a great advantage for both space and frequency freedom, and produce a much better network throughput than traditional systems based on single frequency, omnidirectional transmission. A license‐free bandwidth up to 7 GHz is available centered at 60 GHz. The problem to divide this bandwidth into several channels is described as frequency division issue in this paper. We have provided a possible solution for such a problem in our paper, formulated as a (K,M) list‐coloring problem of the associated graph. Major results are presented based on two different models for connection requests. In addition, a numerical test is performed to verify the analysis. Copyright © 2004 John Wiley & Sons, Ltd.
The relationship of peer victimization to social anxiety and loneliness in adolescent females
Authors: Storch Eric A , Masia‐Warner Carrie
Published: May 2004

This study examined the relationship of overt and relational victimization to social anxiety, loneliness, and prosocial behaviours in a sample of female adolescents. The Social Experience Questionnaire, Social Anxiety Scale for Adolescents, and Asher Loneliness Scale were administered to 561 girls in the ninth, tenth, and eleventh grades of an urban parochial high school. Consistent with prior work, overt and relational victimization were positively associated with fear of negative evaluation, social avoidance of general and new situations, and loneliness. In addition, prosocial behaviours from peers moderated the effects of relational victimization on loneliness. Implications of these findings for the role of peer victimization and prosocial behaviours in female relationships are discussed.
Adolescent adjustment in a nationally collected sample: identifying group differences by adoption status, adoption subtype, developmental stage and gender☆
Authors: Burrow Anthony L , Tubman Jonathan G , Finley Gordon E
Published: May 2004

The current study investigated group differences in adolescent adjustment by adoption status and adoption subtype in a national sample, in contrast to group differences based on developmental stage or gender. Secondary analyses of the National Longitudinal Study of Adolescent Health were performed to describe group differences in a broad range of adjustment measures (a) between adoptees and non‐adoptees, (b) between different‐race adoptees and same‐race adoptees and, (c) across adolescent developmental stage and gender groups. Based upon a developmental deviance hypothesis, the current study hypothesized that early adolescent different‐race adoptees would fair better across measures of academic performance, familial relationships, psychological adjustment, and physical health than their middle and late adolescent counterparts. Group comparisons revealed little evidence of increased maladjustment among adopted adolescents compared to non‐adopted study participants. In addition, group comparisons revealed few differences across indices of adolescent adjustment by adoption subtype (i.e. by the degree of racial congruence adopted child and adoptive parent). However, significant group differences in adolescent adjustment were found based on participants’ developmental stage and gender. The implications of the findings are discussed.
Adolescents define sexual orientation and suggest ways to measure it
Authors: Friedman Mark S , Silvestre Anthony J , Gold Melanie A , Markovic Nina , Savin‐Williams Ritch C , Huggins James , Sell Randal L
Published: May 2004

Researchers disagree on how to assess adolescent sexual orientation. The relative importance of various dimensions (e.g. attraction, relationships, behavior, self‐labeling) is unknown, which calls into question the validity of studies assessing adolescent sexual orientation. To address this issue, 50 male and female adolescents of varied sexual orientations participated in focus groups and interviews. Two types of sexual attraction—one a physiologic reaction and the other a cognitive response—were central to adolescent sexual orientation. Participants did not perceive sexual behavior and self‐identification as necessarily relevant. Preliminary items to measure sexual attraction were developed based on these adolescents’ perceptions.
Youth engaging in online harassment: associations with caregiver–child relationships, Internet use, and personal characteristics☆
Authors: Ybarra Michele L , Mitchell Kimberly J
Published: May 2004

To date, research focused on “traditional” (i.e. in‐person) youth bullying behaviour has documented serious psychosocial challenges for those involved. How this literature translates to youth engaging in aggressive behaviours online has yet to be examined. Using the largest US sample of youth Internet users to date, psychosocial characteristics of youth engaging in Internet harassment were examined. Results from the nationally representative survey suggested that Internet harassment is a significant public health issue, with aggressors facing multiple psychosocial challenges including poor parent–child relationships, substance use, and delinquency. Comparisons to traditional bullies were made, with similarities and differences noted.
Identification of a novel Xenopus laevis poly (A) binding protein
Authors: Cosson Bertrand , Braun Frederique , Paillard Luc , Blackshear Perry , Beverley H. Osborne
Published: June 2004

Summry— Poly (A) binding proteins are intimately implicated in controlling a number of events in mRNA metabolism from nuclear polyadenylation to cytoplasmic translation and stability. The known poly(A) binding proteins can be divided into three distinct structural groups (prototypes PABP1, PABPN1/PABP2 and Nab2p) and two functional families, showing that similar functions can be accomplished by differing structural units. This has prompted us to perform a screen for novel poly(A) binding proteins using Xenopus laevis. A novel poly(A) binding protein of 32 kDa (p32) was identified. Sequence analysis showed that p32 has about 50% identity to the known nuclear poly(A) binding proteins (PABPN1) but is more closely related to a group of mammalian proteins of unknown function. The expression of Xenopus laevis ePABP2 is restricted to early embryos. Accordingly, we propose that p32 is the founder member of a novel class of poly(A) binding proteins named ePABP2.
In vitro studies on Itm2a reveal its involvement in early stages of the chondrogenic differentiation pathway
Authors: Van Den Plas Dave , Merregaert Joseph
Published: June 2004

Summry— The Integral membrane protein 2A (Itm2A) is a transmembrane protein belonging to a family composed of at least two other members, Itm2B and Itm2C, all of them having a different expression pattern. The Itm2a gene serves as a marker for early stages in endochondral ossification. In order to understand the role of Itm2A in this process, expression of the gene was investigated in different cell systems. In C3H10T1/2 cells, the gene was upregulated early on when the cells were induced to the chondrogenic lineage but less to the osteogenic lineage. In MCT cells, expression was upregulated at permissive temperatures but not at non‐permissive temperatures. When induced with insulin, ATDC5 cells expressed Itm2a in early stages but not at late stages. Furthermore, PTH treatment seems to upregulate Itm2a transcription.

In order to understand the role of Itm2a in the chondrogenic differentiation process in more detail, we constitutively overexpressed exogenous Itm2A in mouse ATDC5 cells. Two clones expressing high levels of Itm2a were isolated and characterized. Gene expression analysis of the overexpresser clones demonstrated that expression of collagen type X was delayed. These results demonstrate that overexpression of Itm2a in mouse ATDC5 cells impede the transition to hypertrophic cells. Taken together, our observation supports the involvement of Itm2a in the early stages of chondrogenesis in vitro.
Drosophila cohesins DSA1 and Drad21 persist and colocalize along the centromeric heterochromatin during mitosis
Authors: Valdeolmillos Ana , Rufas Julio S. , Suja José A. , Vass Sharron , Heck Margarete M.S. , Martínez‐A Carlos , Barbero Jose´ L.
Published: June 2004

Summry— Sister chromatid cohesion in eukaryotes is maintained mainly by a conserved multiprotein complex termed cohesin. Drad21 and DSA1 are the Drosophila homologues of the yeast Scc1 and Scc3 cohesin subunits, respectively. We recently identified a Drosophila mitotic cohesin complex composed of Drad21/DSA1/DSMC1/DSMC3. Here we study the contribution of this complex to sister chromatid cohesion using immunofluorescence microscopy to analyze cell cycle chromosomal localization of DSA1 and Drad21 in S2 cells. We observed that DSA1 and Drad21 colocalize during all cell cycle stages in cultured cells. Both proteins remain in the centromere until metaphase, colocalizing at the centromere pairing domain that extends along the entire heterochromatin; the centromeric cohesion protein MEI‐S332 is nonetheless reported in a distinct centromere domain. These results provide strong evidence that DSA1 and Drad21 are partners in a cohesin complex involved in the maintenance of sister chromatid arm and centromeric cohesion during mitosis in Drosophila.
Hepatocyte growth factor disrupts tight junctions in human breast cancer cells
Authors: Martin Tracey A. , Watkins Gareth , Mansel Robert E. , Jiang Wen G.
Published: May 2004

Tight junctions in epithelial cells act as cell—cell adhesion structures and govern paracellular permeability. Disruption of these functions can lead to dissociation of cancer cells. This study aimed to determine whether HGF, a cytokine secreted by stromal cells, is capable of modulating expression and function of tight junction molecules in human breast cancer cell lines. HGF decreased trans‐epithelial resistance and increased paracellular permeability of two human breast cancer cell lines, MDA MB 231 and MCF‐7. Q‐PCR showed that HGF modulated the levels of several tight junction molecule (occludin, claudin‐1 and −5, JAM−1 and −2) mRNA transcripts in MDA MB 231 and MCF‐7 cells. Western blotting and immunohistochemistry also showed modulation of expression of the tight junction molecule, occludin. It is suggested that HGF disrupts tight junction function in human breast cancer cells by effecting changes in the expression of tight junction molecules at both the mRNA and protein levels. We conclude that regulation of tight junctions could be of fundamental importance in the prevention of metastasis of breast cancer cells.