bluuebunny/crossref_metadata_2025 huggingface dataset:
Reliability of aneuploidy estimates in human sperm: Results of fluorescence in situ hybridization studies using two different scoring criteria
Authors: Martin Renée H. , Rademaker Alfred
Published: February 2005

Aneuploidy estimates for chromosomes 1, 12, X, and Y were obtained in human sperm from five donors using multicolor fluorescence in situ hybridization (FISH) analysis. Disomy frequencies were obtained by scoring a minimum of 10,000 sperm for each chromosome probe per donor. This analysis was replicated for two scoring criteria: one used one half of a signal domain as the minimum distance between two signals to be counted as two and thus disomic; the other set one signal domain as the minimum distance between two signals. A total of 120,870 sperm were assessed using one half of a domain as the criterion, and 113,478 were scored using one domain as the criterion. The percentage of disomy for chromosomes 1, 12, X, Y, and XY was 0.18, 0.16, 0.15, 0.19, and 0.25, respectively, using the one‐half‐domain criterion, and 0.08, 0.17, 0.07, 0.12, and 0.16, respectively, using the one‐domain criterion. The percentage of disomy decreased significantly with use of one domain as the minimum distance for signal separation for all chromosomes except for chromosome number 12. These lower disomy frequencies correlated well with frequencies derived from human sperm karyotypes analyzed in our laboratory. This suggests that the fluorescent signals for chromosomes 1, X, and Y split into more than one domain in decondensed interphase sperm, and that the use of the one‐half‐domain criterion would lead to an overestimate of aneuploidy frequencies. The factors known to affect aneuploidy estimates derived from FISH studies are discussed, and recommendations for stringent scoring criteria are proposed. © 1995 wiley‐Liss, Inc.
Localization of epitopes for monoclonal antibodies at the N‐terminus of the porcine zona pellucida glycoprotein pZPC
Authors: Gupta S. K. , Yurewicz Edward C. , Afzalpurkar Abhijit , Rao K. V. S. , Gage Douglas A. , Wu H. , Sacco A. G.
Published: February 2005

Zona pellucida glycoproteins play an important role in fertilization. In this study, attempts have been made to identify and define epitopes of monoclonal antibodies (mAbs) possessing contraceptive efficacy in vitro. The porcine zona glycoprotein pZPC, a homologue of mouse/human ZP3, was reduced and alkylated and subsequently digested with trypsin. Reverse‐phase HPLC of the tryptic digest yielded twenty two peaks (T1–T22). When tested against mAbs reactive against sequential determinants on pZPC, T11 was immunoreactive with two mAbs, mAb‐455 and mAb‐467, as shown by antigen inhibition ELISA. IC50 values of 3.1 nM and 8.6 nM were recorded versus mAb‐455 and mAb‐467 respectively, and approximated the IC50 values obtained with intact pZPC. Amino acid analysis, Edman degradation, and FAB‐MS identified T11 as the N‐blocked decapeptide pyro‐Gln‐Pro‐Val‐Trp‐Gln‐Asp‐Glu‐Gly‐Gln‐Arg derived from the N‐terminus of pZPC. Synthesis of overlapping octapeptides further identified VWQDE and WQDE as the minimum motifs with antigenie activity for mAb‐455 and mAb‐467, respectively. Glycine replacement peptides confirmed residues W,Q,E as critical for binding mAb‐455 and W,Q,D,E as critical for binding mAb‐467. Both mAbs inhibited binding of boar sperm to zona‐encased porcine oocytes. These results, the first to define peptide epitopes of porcine zona glycoprotein, will assist in the design of an immunocontraceptive vaccine based on synthetic peptides corresponding to pZPC or its homologues in other species. © 1995 wiley‐Liss, Inc.
Effect of cysteamine on glutathione level and developmental capacity of bovine oocyte matured in vitro
Authors: de Matos Daniel G. , Furnus Cecilia C. , Moses Daniel F. , Baldassarre Hernan
Published: February 2005

The present study was carried out to evaluate if the addition of cysteamine to the culture medium during in vitro maturation of bovine oocytes increased the glutathione (GSH) levels in the mature oocytes, and if these changes may promote an improvement on in vitro development to the blastocyst stage. Follicular oocytes from slaughterhouse ovaries were matured in TCM 199 supplemented with 10% (v/v) fetal calf serum, hormones, and 0 (control), 25, 50, or 100 μM of cysteamine for 24 hr. After in vitro maturation the oocytes were fertilized and cultured for 8 days. The percentage of embryos that developed to the blastocyst stage was significantly higher (P < 0.01) for oocytes matured in medium containing 100 μM of cysteamine than for those matured in control medium. Moreover, the intracellular GSH levels were increased (P < 0.05) in oocytes matured with 100 μM of cysteamine with respect to control. No differences were observed in maturation and cleavage rates, and in the mean cell numbers per blastocyst among treatments (P > 0.05). These results indicate that the addition of thiol compounds such as cysteamine to maturation medium increases the efficiency of in vitro blastocyst production from immature bovine oocytes. The higher levels of GSH in oocytes matured in the presence of cysteamine suggest that the beneficial effects of cysteamine on in vitro maturation and subsequent development after in vitro fertilization are mediated by GSH. © 1995 wiley‐Liss, Inc.
Bovine oocyte diameter in relation to maturational competence and transcriptional activity
Authors: Fair T. , Hyttel P. , Greve T.
Published: February 2005

The aims of the present series of experiments were to establish a possible relationship between bovine oocyte diameter and follicle size, investigate the developmental ability of oocytes of different diameter groups, and investigate the relationship between oocyte diameter and RNA transcriptional activity of the oocyte.

Follicles were recovered from slaughterhouse ovaries by mechanical dissection, measured, and assigned to one of the following size categories: ≥ 4 mm, <3–4 mm, <2–3 mm, <1–2 mm, and <1 mm. Oocytes were liberated from the follicles and their diameters recorded. The correlation coefficient between oocyte diameter and follicle size was 0.32 (P < 0.0001).

Oocytes were recovered by aspiration and/or slicing of slaughterhouse ovaries and divided into four groups (<100 μm, 100–<110 μm, 110–<120 μm, and >120 μm) based on diameter. Oocytes were processed through standard procedures for in vitro maturation and stained in order to assess nuclear development. Rates of in vitro development to metaphase II were 21.2%, 42.3%, 75.9%, and 80.7%, respectively, for the four groups.

On a separate occasion immature oocytes from the above diameter groups were cultured in the presence of 3H‐uridine for 45 min and scored for degree of RNA synthesis as indicated by the presence of autoradiographic labeling. Oocytes <110 μm showed a greater degree of 3H‐uridine incorporation than those ≥ 110 μm, suggesting that they were involved in RNA synthesis and therefore still in the growth phase. © 1995 wiley‐Liss, Inc.
Mechanisms regulating Raf‐1 activity in signal transduction pathways
Authors: Morrison Deborah K.
Published: February 2005

Raf‐1 is a key protein involved in the transmission of developmental and proliferative signals generated by receptor and nonreceptor tyrosine kinases. Biochemical and genetic studies have demonstrated that Raf‐1 functions downstream of activated tyrosine kinases and Ras and upstream of mitogen‐activated protein kinase (MAPK) and MAPK kinase (MKK or MEK) in many signaling pathways. A major objective of our laboratory has been to determine how Raf‐1 becomes activated in response to signaling events. Using mammalian, baculovirus, and Xenopus systems, we have examined the roles that phosphorylation and protein‐protein interactions play in regulating the biological and biochemical activity of Raf‐1.

Our studies have provided evidence that the activity of Raf‐1 can be modulated by both Ras‐dependent and Ras‐independent pathways. Recently, we reported that Arg89 of Raf‐1 is a residue required for the association of Raf‐1 and Ras. Mutation of this residue disrupted interaction with Ras and prevented Ras‐mediated, but not protein kinase C‐or tyrosine kinase‐mediated, enzymatic activation of Raf‐1 in the baculovirus expression system. Further analysis of this mutant demonstrated that kinase‐defective Raf‐1 proteins interfere with the propagation of proliferative and developmental signals by binding to Ras and blocking Ras function.

Our findings have also shown that phosphorylation events play a role in regulating Raf‐1. We have identified sites of in vivo phosphorylation that positively and negatively alter the biological and enzymatic activity of Raf‐1. In addition, we have found that some of these phosphorylation sites are involved in mediating the interaction of Raf‐1 with potential activators (Fyn and Src) and with other cellular proteins (14‐3‐3). Results from our work suggest that Raf‐1 is regulated at multiple levels by several distinct mechanisms. © 1995 wiley‐Liss, Inc.
LET‐23‐mediated signal transduction during Caenorhabditis elegans development
Authors: Sternberg Paul W. , Lesa Giovanni , Lee Junho , Katz Wendy S. , Yoon Charles , Clandinin Thomas R. , Huang Linda S. , Chamberlin Helen M. , Jongeward Gregg
Published: February 2005

We are using Caenorhabditis elegans vulval induction to study intercellular signaling and its regulation. Genes required for vulval induction include the LIN‐3 transforming α‐like growth factor, the LET‐23 epidermal growth factor (EGF)‐receptor‐like transmembrane tyrosine kinase, the SEM‐5 adaptor protein, LET‐60 Ras, and the LIN‐45 Raf serine/threonine kinase. Inactivation of this pathway results in a failure of vulval differentiation, the “vulvaless” phenotype. Activation of this pathway either by overexpression of LIN‐3, a point mutation in the LET‐23 extracellular domain, or hyperactivity of LET‐60 Ras results in excessive vulval differentiation, the “multivulva” phenotype. In addition to searching for new genes that act positively in this signaling pathway, we have also characterized genes that negatively regulate this inductive signaling pathway. We find that such negative regulators are functionally redundant: mutation of only one of these negative regulators has no effect on vulval differentiation; however, if particular combinations of these genes are inactivated, excessive vulval differentiation occurs. The LIN‐15 locus encodes two functionally redundant products, LIN‐15A and LIN‐15B, that formally act upstream of the LET‐23 receptor to prevent its activity in the absence of inductive signal. The LIN‐15A and B proteins are novel and unrelated to each other. The unc‐101, sli‐1, and rok‐1 genes encode a distinct set of negative regulators of vulval differentiation. The unc‐101 gene encodes an adaptin, proposed to be involved in intracellular protein trafficking. The sli‐1 gene encodes a protein with similarity to c‐cbl, a mammalian proto‐oncogene not previously linked with a tyrosine kinase‐Ras‐mediated signaling pathway. LIN‐3 and LET‐23 are required for several aspects of C. elegans development—larval viability, P12 neuroectoblast specification, hermaphrodite vulval induction and fertility, and three inductions during male copulatory spicule development. Fertility and vulval differentiation appear to be mediated by distinct parts of the cytoplasmic tail of LET‐23, and by distinct signal transduction pathways. © 1995 wiley‐Liss, Inc.
Stability and error analysis on partially implicit schemes
Authors: Sun Tong
Published: February 2005

Subdomain techniques have been widely used for solving elliptic and parabolic equations. For parabolic problems, it is possible to combine subdomain techniques with explicit methods to construct efficient algorithms. In addition, this kind of algorithms is naturally suitable for parallel computing. However, the stability of such schemes has been considered as a very difficult issue. In this article, we use an exact error propagation and discrete scheme smoothing approach to give a posteriori stability and error analysis. © 2005 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2005
Specific in vitro binding of (S,S)‐[3H]MeNER to norepinephrine transporters
Authors: Ghose Subroto , Fujita Masahiro , Morrison Paul , Uhl George , Murphy Dennis L. , Mozley P. David , Schou Magnus , Halldin Christer , Innis Robert
Published: February 2005

The aim of this study was to determine the selectivity of (S,S)‐2‐(α‐(2‐methoxyphenoxy)benzyl)morpholine (MeNER) binding to norepinephrine transporters (NET). Quantitative autoradiography studies of NET binding were performed in brains of wildtype mice and those of mutant mice lacking one or two alleles of the NET gene. [3H]MeNER binding in the wildtype mouse brains was consistent with previously reported distributions of NET. Highest levels were found in the locus coeruleus, thalamus, hypothalamus, and bed nucleus of stria terminalis. Specific binding in these regions was ˜50% in the heterozygous NET mice and negligible in the NET knockout mice. Binding in the wildtype mouse brains was displaced by the NETligand, nisoxetine, but not by the serotonin or dopamine transporter blockers, citalopram or GBR 12935. [3H]MeNER displayed much higher affinity for NET than for SERT or DAT in homogenate binding studies. Each of these features supports thebinding specificity of this candidate in vivo NET ligand. Synapse 56:100–104, 2005. © 2005 Wiley‐Liss, Inc.
Numerical modeling of lava flow cooling applied to the 1997 Okmok eruption: Comparison with advanced very high resolution radiometer thermal imagery
Authors: Patrick M. R. , Dehn J. , Dean K.
Published: February 2005

Throughout February and March 1997, Okmok Volcano, in the eastern Aleutian Islands of Alaska, erupted a 6‐km‐long lava flow of basaltic ′a′a within its caldera. In the first part of the study a numerical model for lava flow cooling was developed by Patrick et al. and applied to the flow to better understand the nature of its cooling. In this second part of the study, the model predictions for lava surface temperature over a 200‐day cooling period were compared to advanced very high resolution radiometer (AVHRR) thermal imagery. Various methods were used to extract the subpixel lava temperature from the AVHRR pixel‐integrated values, including the dual‐band method and pixel merging. Inherent to these approaches is the multicomponent modeling of the lava surface temperature. Whereas active flows have been shown to have several thermal components, so, too, do flows undergoing extended cooling. Because of the dependence of the methods on the AVHRR instantaneous field of view (IFOV), the scan‐dependent IFOV dimensions and overlap values were considered. Results from Patrick et al. indicate that convective heat loss from the surface largely controls surface temperature during extended cooling, but the functions governing this heat loss mechanism are poorly understood. AVHRR‐derived temperatures from this part of the study suggest that values for the convective heat transfer coefficient for this flow were most commonly between 50 and 100 W m−2 K−1 and generally above 25 W m−2 K−1. These results are in agreement with previously measured values from the field but are significantly higher than those assumed in other remote sensing studies of cooling lava. Also, the AVHRR data corroborate the modeled prediction of seasonal warming of the lava surface.
Active geodynamics of the central Mediterranean Sea: Tensional tectonic evidences in western Sicily from mantle‐derived helium
Authors: Caracausi A. , Favara R. , Italiano F. , Nuccio P. M. , Paonita A. , Rizzo A.
Published: February 2005

We report results on the measured high 3He/4He isotope ratio in western Sicily, interpreted together with the heat data. The study of this sector of the Europe‐Africa interaction is crucial to a better understanding of the tectonics and the geodynamical evolution of the central Mediterranean area. The estimated mantle‐derived helium fluxes in the investigated areas are up to 2–3 orders of magnitude greater than those of a stable continental area. The highest flux, found in the southernmost area near the Sicily Channel, where recent eruptions of the Ferdinandea Island occurred 20 miles out to sea off Sciacca, has been associated with a clear excess of heat flow. Our results indicate that there is an accumulation of magma below the continental crust of western Sicily that is possibly intruding and out‐gassing through roughly N‐S trending deep fault systems linked to the mantle, that have an extensional component. Although the identification of these faults is not sufficiently constrained by our data, they could possibly be linked to the pre‐existing faults that originated during the Mesozoic extensional‐transtensional tectonic phases.
Growth of South Rough Ridge, Central Otago, New Zealand: Using in situ cosmogenic isotopes and geomorphology to study an active, blind reverse fault
Authors: Bennett Eleanor R. , Youngson John H. , Jackson James A. , Norris Richard J. , Raisbeck Grant M. , Yiou Françoise , Fielding Eric
Published: February 2005

In situ cosmogenic 10Be and 26Al measurements on sedimentary quartzites, together with analysis of abandoned river terraces, can be used to show how drainage responded to the lateral propagation of a late Quaternary anticline forming above a blind reverse fault in Central Otago, New Zealand. A close link between the progression of cosmogenic ages and the tectonic geomorphology allows us to confirm that uplift and propagation rates on the anticline are in the ranges 0.08–0.12 mm yr−1 and 0.8–1.5 mm yr−1, respectively, over the last 550,000 years. The agreement between the isotopic and geomorphological evidence in turn requires that minimum 10Be exposure ages as great as 660 ka are not in steady state with respect to erosion. This is a geochemical result of significance, as it opens the possibility of a more regional analysis of landscape evolution in this region, using the same rocks. On an adjacent anticline, thought to be even older on geomorphological arguments, 10Be concentrations give minimum exposure ages in the range 750–1400 ka. These extremely old minimum ages are rare worldwide, as they are usually limited to smaller values by erosion. They are attributable to the very resistant nature of the quartz‐rich boulders in which the measurements were made, which in places are shown to have erosion rates lower than 0.5 mm kyr−1.
Study of the Sea‐Viewing Wide Field‐of‐View Sensor (SeaWiFS) aerosol optical property data over ocean in combination with the ocean color products
Authors: Wang Menghua , Knobelspiesse Kirk D. , McClain Charles R.
Published: February 2005

The primary goals of the Sea‐Viewing Wide Field‐of‐View Sensor (SeaWiFS) are to routinely provide the global ocean color and ocean bio‐optical property data. In retrieving the ocean near‐surface signals from SeaWiFS‐measured radiances, however, the aerosol effects must be accurately estimated and removed. Therefore SeaWiFS also produces the aerosol optical property data (in particular, the aerosol optical thickness and Ångström exponent) over global ocean. Since September of 1997, SeaWiFS has generated both global aerosol (over ocean) and ocean color data for more than 6.5 years and is still in producing these products with very good sensor performance. This makes SeaWiFS the longest in history for providing simultaneously the global aerosol and ocean color products. In this paper we describe the SeaWiFS aerosol products over ocean in combination with the ocean color data. We assert through various examples that, because SeaWiFS simultaneously retrieves both atmospheric and ocean color data, the SeaWiFS products are useful to study aerosol and ocean variations in climatic forcing, biogeochemical cycling, and radiative effects in the global and regional scales.
Hypoxic Preconditioning and Tolerance via Hypoxia Inducible Factor (HIF) 1α-linked Induction of P450 2C11 Epoxygenase in Astrocytes
Authors: Liu Mingyue , Alkayed Nabil J
Published: February 2005

The brain's adaptive response to ischemic preconditioning (IPC) is mediated in part via hypoxia inducible factor (HIF)-responsive genes. We previously showed that IPC induces cytochrome P450 2C11 expression in the brain, associated with protection from stroke. Cytochrome P450 2C11 is an arachidonic acid (AA) epoxygenase expressed in astrocytes, which metabolizes AA to epoxyeicosatrienoic acids (EETs). We tested the hypotheses that hypoxic preconditioning (HPC) induces 2C11 expression in astrocytes via HIF-1α, and that the P450 epoxygenase pathway contributes to enhanced astrocyte tolerance to ischemia-like injury induced by oxygen-glucose deprivation (OGD). Primary cultured astrocytes were incubated under normoxic or hypoxic conditions for 1, 3, 6, 24, or 48 h, and protein levels of P450 2C11 and HIF-1α were measured by Western blotting. Additionally, 2C11 mRNA was measured by Northern blotting, and binding of HIF-1α to 2C11 promoter was evaluated using electrophoretic mobility shift assay (EMSA) with 2C11 promoter DNA containing putative HIF-binding sites. Levels of 2C11 mRNA and protein were significantly increased starting at 3 and 6 h of hypoxia, respectively. The increase in 2C11 expression was preceded by an increase in HIF-1α protein at 1 h of hypoxia, and EMSA showed a specific and direct interaction between 2C11 promoter DNA and HIF-1α in nuclear extracts from astrocytes. HPC and EETs reduced astrocyte cell death, and P450 epoxygenase inhibition prevented protection by HPC. We conclude that HPC induces tolerance in astrocytes, at least in part, via HIF-1α-linked upregulation of P450 2C11.
Osteogenic pulmonary metastases originating from a phyllodes tumour of the breast with osteosarcomatous differentiation
Authors: Bhartia SK , Kashyap P
Published: February 2005

Malignant phyllodes tumour is an uncommon breast neoplasm which undergoes osteosarcomatous differentiation in 1.3% of cases. We document the plain film, CT and scintigraphic features of a case of pulmonary metastases from this rare primary tumour.
Time-resolved electrometric and optical studies on cytochrome
bd
suggest a mechanism of electron-proton coupling in the di-heme active site
Authors: Belevich Ilya , Borisov Vitaliy B. , Zhang Jie , Yang Ke , Konstantinov Alexander A. , Gennis Robert B. , Verkhovsky Michael I.
Published: February 2005

Time-resolved electron transfer and electrogenic H
+
translocation have been compared in a
bd
-type quinol oxidase from
Escherichia coli
and its E445A mutant. The high-spin heme
b
595
is found to be retained by the enzyme in contrast to the original proposal, but it is not reducible even by excess of dithionite. When preincubated with the reductants, both the WT (
b
558
2+
,
b
595
2+
,
d
2+
) and E445A mutant oxidase (
b
558
2+
,
b
595
3+
,
d
2+
) bind O
2
rapidly, but formation of the oxoferryl state in the mutant is ≈100-fold slower than in the WT enzyme. At the same time, the E445A substitution does not affect intraprotein electron re-equilibration after the photolysis of CO bound to ferrous heme
d
in the one-electron-reduced enzyme (the so-called “electron backflow”). The backflow is coupled to membrane potential generation. Electron transfer between hemes
d
and
b
558
is electrogenic. In contrast, electron transfer between hemes
d
and
b
595
is not electrogenic, although heme
b
595
is the major electron acceptor for heme
d
during the backflow, and therefore is not likely to be accompanied by net H
+
uptake or release. The E445A replacement does not alter electron distribution between hemes
b
595
and
d
in the one-electron reduced cytochrome
bd
[E
m
(
d
) > E
m
(
b
595
), where E
m
is the midpoint redox potential]; however, it precludes reduction of heme
b
595
, given heme
d
has been reduced already by the first electron. Presumably, E445 is one of the two redox-linked ionizable groups required for charge compensation of the di-heme oxygen-reducing site (
b
595
,
d
) upon its full reduction by two electrons.
Dissection of synaptic excitability phenotypes by using a dominant-negative Shaker K
+
channel subunit
Authors: Mosca Timothy J. , Carrillo Robert A. , White Benjamin H. , Keshishian Haig
Published: February 2005

During nervous system development, synapses undergo morphological change as a function of electrical activity. In
Drosophila
, enhanced activity results in the expansion of larval neuromuscular junctions. We have examined whether these structural changes involve the pre- or postsynaptic partner by selectively enhancing electrical excitability with a Shaker dominant-negative (SDN) potassium channel subunit. We find that the SDN enhances neurotransmitter release when expressed in motoneurons, postsynaptic potential broadening when expressed in muscles and neurons, and selectively suppresses fast-inactivating, Shaker-mediated I
A
currents in muscles. SDN expression also phenocopies the canonical behavioral phenotypes of the
Sh
mutation. At the neuromuscular junction, we find that activity-dependent changes in arbor size occur only when SDN is expressed presynaptically. This finding indicates that elevated postsynaptic membrane excitability is by itself insufficient to enhance presynaptic arbor growth. Such changes must minimally involve increased neuronal excitability.
Genomic characterization of non-O1, non-O139
Vibrio cholerae
reveals genes for a type III secretion system
Authors: Dziejman Michelle , Serruto Davide , Tam Vincent C. , Sturtevant Derek , Diraphat Pornphan , Faruque Shah M. , Rahman M. Hasibur , Heidelberg John F. , Decker Jeremy , Li Li , Montgomery Kate T. , Grills George , Kucherlapati Raju , Mekalanos John J.
Published: February 2005

Non-O1, non-O139
Vibrio cholerae
can cause gastroenteritis and extraintestinal infections, but, unlike O1 and O139 strains of
V. cholerae
, little is known about the virulence gene content of non-O1, non-O139 strains and their phylogenetic relationship to other pathogenic
V. cholerae
. Comparative genomic microarray analysis of four pathogenic non-O1, non-O139 strains indicates that these strains are quite divergent from O1 and O139 strains. Genomic sequence analysis of a non-O1, non-O139 strain (AM-19226) that appeared particularly pathogenic in experimental animals suggests that this strain carries a type III secretion system (TTSS) that is related to the TTSS2 gene cluster found in a pandemic clone of
Vibrio parahaemolyticus
. The genes for this
V. cholerae
TTSS system appear to be present in many clinical and environmental non-O1, non-O139 strains, including at least one clone that is globally distributed. We hypothesize that the TTSS present in some pathogenic strains of non-O1, non-O139
V. cholerae
may be involved in the virulence and environmental fitness of these strains.
Antagonist of growth hormone-releasing hormone induces apoptosis in LNCaP human prostate cancer cells through a Ca
2+
-dependent pathway
Authors: Rekasi Zoltan , Czompoly Tamas , Schally Andrew V. , Boldizsar Ferenc , Varga Jozsef L. , Zarandi Marta , Berki Timea , Horvath Reka A. , Nemeth Peter
Published: February 2005

Antagonists of growth hormone-releasing hormone (GHRH) exert antiproliferative effects directly on cancer cells, which are mediated by the tumoral GHRH receptors. However, the signal transduction pathways involved in antiproliferative effect of GHRH antagonists have not yet been elucidated. We used flow cytometry to investigate whether GHRH antagonist JV-1-38 can induce changes in the cytosolic free Ca
2+
concentration leading to apoptosis in LNCaP human prostate cancer cells. JV-1-38 evoked prompt Ca
2+
signal in a dose-dependent way (1–10 μM) and induced early stage of apoptosis in LNCaP human prostate cancer cells at a concentration effective in suppression of cell proliferation (10 μM) peaking after 3 h. Unexpectedly, agonist GHRH(1–29)NH
2
, which elevates cytosolic free Ca
2+
concentration in pituitary somatotrophs at nanomolar concentrations, failed to induce Ca
2+
signal or apoptosis even at a 10-fold higher concentration (100 μM). However, agonist GHRH(1–29)NH
2
inhibited JV-1-38-induced Ca
2+
signals in a dose-dependent way without affecting the antagonist-induced apoptosis. Peptides unrelated to GHRH did not induce Ca
2+
signals in LNCaP human prostate cancer cells. EDTA (10 mM) or nifedipine (10 μM) significantly reduced the Ca
2+
signal and early stage of apoptosis induced by JV-1-38, supporting the view that the increase in intracellular Ca
2+
in response to JV-1-38 occurs primarily through extracellular Ca
2+
entry through voltage-operated Ca
2+
channels. In conclusion, GHRH antagonists activate tumoral GHRH receptors and are able to induce apoptosis in LNCaP human prostate cancer cells through a Ca
2+
-dependent pathway. Treatment with GHRH antagonists may offer a new approach to the therapy of prostate and other hormone-sensitive cancers.
DNA coiled coils
Authors: Campos J. L. , Urpí L. , Sanmartín T. , Gouyette C. , Subirana J. A.
Published: February 2005

We report the coiled-coil structure of DNA, which is generated by the dodecanucleotide d(ATATATATATAT). The structure has been determined by single-crystal x-ray crystallography. The molecules form duplexes with single-stranded overhangs, which associate with neighbor molecules and give rise to infinite double helices in a coiled-coil conformation, with staggered nicks in both strands. The coiled coils have six dodecamer duplexes per turn. Despite the presence of nicks, the structure is very rigid. Statistical disorder is present, which gives rise to continuous scattering along the layer lines. This observation can be interpreted by the classical theory of coiled coils developed for proteins, which we apply here to a DNA structure. A clear splitting of the original layer lines of the DNA double helix is detected. The structure we have found adds a previously unrecognized element to the architectures that can be built from DNA oligonucleotides. Any duplex with complementary single-strand overhangs should be expected to give rise to regular coiled-coil structures.
Barx2 functions through distinct corepressor classes to regulate hair follicle remodeling
Authors: Olson Lorin E. , Zhang Jie , Taylor Havilah , Rose David W. , Rosenfeld Michael G.
Published: February 2005

The hair-growth cycle, a complex biological system requiring coordinate alterations in gene expression and cellular behavior, provides a challenging model for investigating the interplay of specific transcriptional regulation events. Here we report that the Barx2 homeodomain factor serves as a regulator of hair follicle remodeling (catagen), and loss of
Barx2
in mice causes a defect both in the initiation and progression of catagen, resulting in a protracted first catagen, and later, causing short hair in adult gene-deleted mice. Barx2 negatively regulates its own promoter, and our study highlights the role of Barx2 as a repressor in the skin that can, unexpectedly, functionally interact with two WD40-domain factors distantly related to the yeast corepressor Tup1. These two corepressors, transducin-like enhancer of split and transducin β-like 1, function through distinct and independent interactions with Barx2 for the repression of gene targets, including the
Barx2
gene itself, emphasizing the roles of complementary repression strategies in engrailed homology-1 motif-containing homeodomain factors. Together, our data suggest that the hair-remodeling defect of
Barx2
mutant mice could be explained, in part, by failure to repress one or more critical target genes.
Synergistic proinflammatory responses induced by polymicrobial colonization of epithelial surfaces
Authors: Ratner Adam J. , Lysenko Elena S. , Paul Marina N. , Weiser Jeffrey N.
Published: February 2005

The epithelial surfaces of the upper respiratory tract are continuously exposed to a wide variety of commensal microorganisms. In addition to acting as a physical barrier, epithelial cells respond to specific microbial products with the generation of signals, such as cytokines, that trigger inflammation. Because they are common components of the nasopharyngeal flora that share the potential to cause disease, we investigated the effects ofHaemophilus influenzaeandStreptococcus pneumoniae, alone and in combination, on human respiratory epithelial cells in culture and in a murine model of nasopharyngeal colonization. Exposure of A549 or Detroit 562 epithelial cells to bothS. pneumoniaeandH. influenzaeled to a synergistic increase in production of IL-8, the major neutrophil chemokine in the airway, through an NF-κB-dependent mechanism. Likewise, nasal cocolonization of mice caused a synergistic rise in local production of macrophage inflammatory protein 2 in nasal lavage fluid and subsequent recruitment of neutrophils. This synergistic effect depended on production of the pore-forming cytolytic toxin, pneumolysin, byS. pneumoniaeand activation of host p38 mitogen-activated protein kinase. Although bothH. influenzaeandS. pneumoniaehave ligands for Toll-like receptors (TLRs) TLR2 and TLR4, synergistic activation was TLR2- and TLR4-independent. Thus, epithelial surfaces are capable of amplifying proinflammatory responses during concurrent stimulation by multiple microbial species. These synergistic responses, demonstrated bothin vitroandin vivo, may contribute to inflammation of heavily colonized mucosal barriers.
The nature and purpose of the DBA
Authors: Sarros James C. , Willis Robert J. , Palmer Gill
Published: February 2005

Purpose

To explore the nature (component parts, degree structure) and purpose (intended outcomes) of the Doctor of Business Administration (DBA) degree, identifying the strengths and weaknesses of the degree as they stand presently, using Australian experience.

Design/methodology/approach

A review of DBA programme offerings in Australia identified commonalities and differences in these offerings, and provided information necessary to propose strategic and theoretical implications of DBA education.

Findings

The paper demonstrates areas of confusion surrounding the purpose and nature of the DBA degree, especially as a research degree in comparison to the PhD. It concludes that quality controls are needed to ensure that this growing addition to management education adds to, and aids, the goal of strengthening management research, in ways that link theoretical insights with management practice.

Research limitations/implications

Theoretical and practical implications of the DBA degree are offered, as well as the extent to which the DBA addresses the educational needs of students and its benefits to the university.

Practical implications

The paper provides data useful to administrators interested in establishing a DBA degree in their institution, for researchers wishing to further explore and contribute to the discourse regarding the calibre and content of DBA degrees, and for students wishing to learn more about the fundamental differences between the PhD and the DBA.

Originality/value

This paper provides new information about the way the DBA degree is developing in an Australian context, and offers advice on issues that need attention in order to further ground the DBA in a combined research and practitioner ethic.
The management of human resources in project management‐led organizations
Authors: Clark Ian , Colling Trevor
Published: February 2005

Purpose

The paper examines the operational impact of project management systems on the management of human resources and the practical implications of this for practitioners in two project‐led engineering contractors

Design/methodology/approach

The paper achieves these objectives through semi‐structured interviews in two in‐depth case studies.

Findings

The paper examines specific human resource practices, for example, staff appraisal and efforts at work re‐structuring. The paper finds that in project‐led organizations, such as those in engineering contracting, embedded sectoral characteristics such as portfolio training limit the capacity of HR practitioners to actively change employee perceptions of their development.

Research limitations/implications

The paper reports on sector‐specific research. However, the paper does illustrate the lack of engagement between project management literatures and personnel/HR literatures on the role of HR practitioners in project‐led organizations

Practical implications

The paper draws out the impact of embedded sector effects on the management of HRs and the effects of this on the role played by practitioners.

Originality/value

The value of this paper for the academic community is that it emphasizes a lack of engagement between project management literatures and HR/personnel literatures when it is likely that “project management” systems are a core managerial mechanism for the deployment of staff.
Check‐up time
Authors: Rockman Ilene F.
Published: February 2005

Purpose

Draws parallels between individuals and organizations, and notes the importance of having regular, periodic organizational checks to avoid incurring serious problems.

Design/methodology/approach

Suggests collecting and analyzing appropriate data, and getting a second opinion when necessary, as a strategy to better understand an organization's health.

Findings

Being clear about one's purpose, strategic initiatives, and/or goals – what one intends to learn, and how one plans to use the findings – is of uppermost importance.

Originality/value

Outlines the order in which data should be collected and how to use the information found.
Enhancing library instruction with peer planning
Authors: Finley Priscilla , Skarl Susie , Cox Jennifer , VanderPol Diane
Published: February 2005

Purpose

One of the primary goals of the project was to create a supportive environment for experimentation to enhance classroom effectiveness.

Design/methodology/approach

A group of librarians, the enhancement team, scheduled brainstorming sessions with instructors interested in making changes in their classroom approaches. At the brainstorming plans for session objectives, activities, timing, roles and desired outcomes were made for a specific upcoming class. Most participating instructors chose to enhance their classes by trying either an active learning activity or a group work activity that was new to them. A member of the enhancement team attended each of the peer‐planned sessions to take notes and act as an observer, assistant or team teacher, as requested by the instructor. The instructors who participated also filled out brief assessment forms.

Findings

Although neither the non‐library faculty nor the students were formally surveyed, the active learning techniques used in the one‐shots received positive feedback. In particular, several teaching faculty told the library instructors at the end of the classes that the immediate hands‐on activities and the group activities aided the students’ comprehension of materials. In addition, a majority of the library instructors noted in their follow‐up surveys that the students were noticeably more engaged in the learning process during these classes.

Originality/value

The model of peer coaching at the planning stage, combined with team teaching, will be used to introduce new staff to teaching in the UNLV Libraries’ instruction department and continuing staff will be encouraged to open their classrooms to colleagues for ongoing professional development and constructive peer evaluation.
The vision solution to direct part mark identification
Authors: Rooks Brian
Published: February 2005

Purpose

To discuss the application of direct part marking identification (DPMI) using 2D matrix codes, the use of which is increasing in industries as diverse as automotive and medical instruments.Design/methodology/approach – The benefits of 2D codes are explained, emphasising that they have sufficient storage capacity to provide data for tracking a part during its manufacture and through the supply chain and allow traceability throughout its lifetime. It describes the operation of Cognex, one of the leading manufacturers of ID products and also the world's largest supplier of machine vision systems is Cognex. It explains that initially the electronics industry exploited Cognex' code reading technology and an application at a German board manufacturer is described. Another system, at a diesel engine injector manufacturer in France, has 42 Cognex systems reading 2D codes and guiding robots in assembly. Also described is a new range of Cognex hand‐held and fixed‐mount 1D and 2D code readers “loaded” with software that allows reading in difficult conditions and with degraded or partially obscured codes.Findings – The DPMI market has expanded into industries other than automotive, which has prompted Cognex to establish a new division of ID products.Originality/value – The paper emphasises the importance of 2D codes in product traceability and indicates how vision technology is being utilised to read these codes even under difficult conditions.
Old and new at Automatica exhibition
Authors: Braggins Don
Published: February 2005

Purpose

A review of selected vision exhibits and innovations at a new biennial international trade fair in Germany, which essentially replaces the traditional substantial vision presence at the annual Hanover Industry Fair.Design/methodology/approach – Five companies are profiled; four (ISRA Vision, Vitronic, AKATech, and INOS Automation) with innovative products and one (Stemmer Imaging) with a highly European approach to marketing.Findings – One claimed innovation was foreshadowed 20 years ago, but this time it works! Many successful applications of machine vision are now in sectors outside the traditional manufacturing field. These include logistics and aspects of traffic management. The ability to measure moving items accurately was a major advance.Originality/value – This will alert vision practitioners, and researchers intent on commercialisation, who did not get to Munich to the latest developments and opportunities for commercial exploitation of automated imaging technology. It will help them to judge whether a visit to the next event in May 2006 will be justified.
UK start‐up poised to take the fibre optic sensor market by storm
Authors: Bogue Robert W.
Published: February 2005

Purpose

To describe a new optical fibre Bragg grating (FBG) sensor system, based on a novel time division multiplexing technique, which is being commercialised by UK start‐up Insensys. This new technique allows sensor costs to be reduced dramatically and also yields operational benefits.Design/methodology/approach – The system uses time division multiplexing (TDM) rather than wavelength division multiplexing (WDM) to interrogate the sensors. All the FBG sensors are written at the same wavelength and the interrogation unit receives a number of pulses from each grating. These pulses arrive at a time determined by the grating distance from the interrogator and one grating sensor can be distinguished from another by analysing the pulse arrival times. As a result, there is no need for a tuneable laser or filter and a single mask can be used to write all of the gratings, thus reducing both manufacturing and component costs.Findings – This design has led to lower costs and allows up to 100 strain or temperature sensors to be incorporated into a single channel system, rather than around 4, which is the norm for conventional WDM systems. The company is now in production and has orders for systems to monitor the strain in wind turbine blades, to measure temperature profiles in oil wells and to monitor the stress in composite structures.Originality/value – This TDM‐based design allows FBG sensor systems to measure far more points per fibre than is possible with conventional WDM system, combined with lower system costs. Applications are being found in the marine, aerospace, offshore and power generation industries.
Korean researchers break fibre optic sensor distance record
Authors: Bogue Robert W.
Published: February 2005

Purpose

To describe a new technique, developed in Korea, which extends the operational length of fibre Bragg grating strain and temperature sensors to approximately 50 km. It is based on distributed Raman amplification.Design/methodology/approach – The system uses a single pump source to achieve distributed Raman amplification in the transmission optical fibre and does not employ an additional broadband light source, as the residual pump power after the transmission fibre is recycled to generate broadband amplified spontaneous emission in an erbium‐doped fibre.Findings – The temperature and strain response of the system was tested by measuring changes in reflection from the sensor which were captured on an optical spectrum analyser, located at the end of a 50 km length of fibre. The thermal sensitivity was found to be 8.2 pm/°C over the range 30‐100°C and a strain sensitivity of 1.1 pm/με was exhibited between 0 and 1,700 με. The measurement resolutions of the system for temperature and strain were estimated at 0.7°C and 8.64 με, respectively. The signal‐to‐noise ratio was approximately 11 dB.Originality/value – This work has shown that the use of distributed Raman amplification can extend the operational length of fibre Bragg grating sensors from around 25 km to at least 50 km, whilst achieving good strain and temperature sensitivities.
New optical airspeed sensor poised to cut airline costs
Authors: Bogue Robert W.
Published: February 2005

Purpose

To describe a new laser‐based, optical airspeed sensor development project. Dubbed laser air speed sensor instrument (LASSI), the sensor aims to overcome certain operational limitations of existing devices used on aircraft.Design/methodology/approach – The LASSI system is being developed by a consortium of UK organisations. It relies on Doppler wavelength shifting and involves firing short duration laser pulses from the aircraft into the atmosphere and measuring the velocity‐induced Doppler shift in the reflected (Rayleigh scattered) signal. The source is a diode‐pumped Nd:YAG laser operating at UV wavelengths.Findings – The project has reached the stage where a prototype system test bed is being assembled. Preliminary findings suggest that the system will offer a number of operational and economic benefits over existing devices, notably Pitot tubes.Originality/value – This new optical system is expected to improve helicopter safety during low‐speed activities, yield fuel savings on long‐haul passenger aircraft through a reduction in drag and also reduce the radar cross‐section of military aircraft.
Reducing uncertainty in low flows for bench‐top wind tunnels
Authors: Hardy J.E. , McKnight T.E.
Published: February 2005

Purpose

Bench‐top wind tunnels are used extensively by the US Air Force for calibrating anemometers. As anemometers have improved, the need for reduced uncertainties in the bench‐top wind tunnels was required. A three‐pronged approach was used to reduce low velocity uncertainties by a factor of 2‐3.Design/methodology/approach – The reduction in velocity uncertainties was achieved by upgrading the wind tunnel instrumentation that measured the pressure and differential pressure and by improving the velocity calibration of the bench‐top wind tunnel. A detailed uncertainty analysis was performed to determine how much the instrumentation needed to improve. A laser Doppler velocimetry (LDV) was used to calibrate each wind tunnel at low velocities.Findings – The uncertainty analysis indicated that the main contributors to the velocity uncertainty were the differential pressure and the pressure measurements. These two process instruments were upgraded to reduce their individual uncertainties by a factor of 2. Additionally each bench‐top wind tunnel was calibrated using the LDV with special emphasis on flows from 0.15‐3.0 m/s. In all, nine wind tunnels were calibrated and the upgraded systems exhibited a reduction in uncertainties in the low flow region of a factor of 2‐3.Originality/value – A need to reduce velocity uncertainties in bench‐top wind tunnels was a requirement for the US Air Force calibration program. Upgraded instrumentation and individual calibration with an LDV provided the needed reduction. In the low flow region of 0.15 to 3.0 m/s, uncertainties were reduced by a factor of 2‐3.