bluuebunny/crossref_metadata_2025 huggingface dataset:
RECENT HERMES RESULTS ON MESON PRODUCTION
Authors:   ON BEHALF OF THE HERMES COLLABORATION., TYTGAT MICHAEL
Published: March 2005

An overview is given of selected recent HERMES results involving meson production. Topics including single and double spin asymmetries in semi-inclusive and exclusive meson production, hard exclusive production of pion pairs and quark fragmentation in nuclei will be presented.
COMMENTS ON RADIATIVE Kl3 DECAYS
Authors: VERBENI M. , GASSER J. , KUBIS B. , PAVER N.
Published: March 2005

In this talk, I discuss the present experimental and theoretical status of radiative Kl3 decays, with particular emphasis on the possible determination of the structure dependent contributions.
TWO-PION PRODUCTION IN THE PION-NUCLEON REACTION
Authors: KREWALD S. , SCHNEIDER S. , MEIßNER U.-G.
Published: March 2005

Two-pion production in the pion-nucleon reaction is studied in a meson-exchange model with resonances. The model matches with chiral perturbation theory in the threshold region and includes unitarization effects at the two-particle level. Results are compared with the recent BNL data.
TRANSVERSE MOMENTUM DISTRIBUTIONS OF NEUTRAL PIONS PRODUCED AT DEEP SUBTHRESHOLD ENERGIES
Authors: YAHLALI N. , DÍAZ J. , APHECETCHE L. , D'ENTERRIA D. G. , MARTINEZ G. , SCHUTZ Y. , TURRISI R. , VAN GOETHEM M. J. , HOEFMAN M. , LOEHNER H. , OSTENDORF R. W. , SCHADMAND S. , WILSCHUT H. , KUGLER A. , WAGNER W.
Published: March 2005

We present in this paper transverse momentum distributions of π0-mesons measured in 36 Ar +197 Au reactions at 25A and 35A MeV beam energies with the spectrometer TAPS at the KVI AGOR accelerator. Our data are consistent with thermal-like emission of π0-mesons with temperature parameters much lower than in earlier measurements.
π+-π- ASYMMETRY AND THE NEUTRON SKIN IN HEAVY NUCLEI
Authors: SZCZUREK A. , PAWŁOWSKI P.
Published: March 2005

In heavy nuclei the spatial distribution of protons and neutrons is different. At CERN SPS energies production of π+ and π- differs for pp, pn, np and nn scattering. These two facts lead to an impact parameter dependence of the π+ to π- ratio in 208Pb+208Pb collisions. A recent experiment at CERN seems to confirm qualitatively these predictions. It may open a possibility for determination of neutron density distribution in nuclei.
NEAR THRESHOLD η-MESON PRODUCTION IN THE dd→4Heη REACTION
Authors:   FOR THE ANKE COLLABORATION., WROŃSKA A. , HEJNY V.
Published: March 2005

Investigation of the dd→4 He η reaction has been a part of the experimental program at the ANKE facility of COSY-Jülich. It comprises measurements at four excess energies: 2.3 MeV, 7.7 MeV, 22 MeV, 42.7 MeV as well as an energy below threshold for background study. The results obtained so far as well as the employed experimental technique are presented.
MULTIPIONIC FINAL STATES AT CELSIUS/WASA
Authors:   FOR THE CELSIUS/WASA COLLABORATION., PAULY C. , DEMIRÖRS L. , KLOSE V. , SCOBEL W. , KOCH I.
Published: March 2005

The simultaneous measurement of prompt and resonant 3π0 production at CELSIUS/WASA is used to deduce an upper limit for the pp→pp3π0 cross section of σ=1μb for Tp=1360 MeV . A preliminary determination of the slope parameter α for the η→3π0 Dalitz plot based on ca. 11700 events agrees in sign with the world average.
PRODUCTION OF η MESONS IN PROTON-PROTON COLLISIONS CLOSE TO THRESHOLD
Authors: CZYŻYKIEWICZ R. , ADAM H.-H. , BUDZANOWSKI A. , GRZONKA D. , JANUSZ M. , JARCZYK L. , KAMYS B. , KHOUKAZ A. , KILIAN K. , KLAJA P. , KOWINA P. , MOSKAL P. , OELERT W. , PISKOR-IGNATOWICZ C. , PRZERWA J. , ROŻEK T. , SANTO R. , SEFZICK T. , SIEMASZKO M. , SMYRSKI J. , TÄSCHNER A. , WINTER P. , WOLKE M. , WÜSTNER P. , ZIPPER W.
Published: March 2005

A brief experimental overview on the close-to-threshold η meson production in proton-proton interactions is presented and the available observables in measurements with unpolarized and polarized beam and target are discussed.
IDENTIFICATIONS OF HASLER'S CLASSES OF LINEAR RESISTIVE CIRCUIT STRUCTURES
Authors: CEL J.
Published: March 2005

Formulae on first and second derivatives of various functions associated with a linear nullator–norator–resistance network such as total input power, driving-point and transfer resistances with respect to parameters are established. As a consequence, the concavity of the driving-point resistance with respect to the system of parameters is obtained which generalizes a scalar result of Schneider. An example is given showing that the driving-point resistance R of a nonreciprocal one-port is not monotone or convex or concave with respect to the system of resistances which shows that the Cohn–Vratsanos and the Shannon–Hagelbarger theorems which characterize R of reciprocal one-port cannot be extended in this way. Next, a simplified variant of the Shannon–Hagelbarger theorem is used to derive separate necessary and sufficient conditions characterizing always well-posed, sometimes ill-posed and always ill-posed classes of linear resistive circuit structures introduced and characterized by Hasler, both new in formulation and proof. This reveals that the form of the second partial derivative of the resistance function is responsible for various kinds of the structural solvability of linear circuits. Alternative "if and only if" criteria for these classes are established. They involve replacements of reciprocal circuit elements by combinations of contractions and removals leading to pairs of complementary directed nullator and directed norator trees with appropriately defined signs, and resemble therefore earlier famous Willson–Nielsen feedback structure and Chua–Nishi cactus graph criteria for circuits containing traditional controlled sources. Finally, the qualitative parts of the Cohn–Vratsanos and the Shannon–Hagelbarger theorems are shown to be simple consequences of much more general principles governing all aspects of life, such as maximal entropy and energy conservation laws.
UNCERTAINTY MODELING USING FUZZY ARITHMETIC BASED ON SPARSE GRIDS: APPLICATIONS TO DYNAMIC SYSTEMS
Authors: KLIMKE ANDREAS , WILLNER KAI , WOHLMUTH BARBARA
Published: March 2005

Fuzzy arithmetic provides a powerful tool to introduce uncertainty into mathematical models. With Zadeh's extension principle, one can obtain a fuzzy-valued extension of any real-valued objective function. An efficient and accurate approach to compute expensive multivariate functions of fuzzy numbers is given by fuzzy arithmetic based on sparse grids. In this paper, we illustrate the general applicability of this new method by computing two dynamic systems subjected to uncertain parameters as well as uncertain initial conditions. The first model consists of a system of delay differential equations simulating the periodic outbreak of a disease. In the second model, we consider a multibody mechanism described by an algebraic differential equation system.
FUZZY CLASS LOGISTIC REGRESSION ANALYSIS
Authors: YANG MIIN-SHEN , CHEN HWEI-MING
Published: March 2005

Distribution mixtures are used as models to analyze grouped data. The estimation of parameters is an important step for mixture distributions. The latent class model is generally used as the analysis of mixture distributions for discrete data. In this paper, we consider the parameter estimation for a mixture of logistic regression models. We know that the expectation maximization (EM) algorithm was most used for estimating the parameters of logistic regression mixture models. In this paper, we propose a new type of fuzzy class model and then derive an algorithm for the parameter estimation of a fuzzy class logistic regression model. The effects of the explanatory variables on the response variables are described. The focus is on binary responses for the logistic regression mixture analysis with a fuzzy class model. An algorithm, called a fuzzy classification maximum likelihood (FCML), is then created. The mean squared error (MSE) based accuracy criterion for the FCML and EM algorithms to the parameter estimation of logistic regression mixture models are compared using the samples drawn from logistic regression mixtures of two classes. Numerical results show that the proposed FCML algorithm presents good accuracy and is recommended as a new tool for the parameter estimation of the logistic regression mixture models.
SYMMETRIC DIFFERENTIATION AND HAMILTONIAN OF A QUANTUM STOCHASTIC PROCESS
Authors: VON WALDENFELS WILHELM
Published: March 2005

The main object of this paper is to establish the Hamiltonian of the Hudson–Parthasarathy quantum stochastic differential equation [Formula: see text] As its solution forms a cocycle with respect to the time shift, its product with the time shift establishes a strongly continuous one-parameter unitary group W(t)= exp (-itH) and H is called its Hamiltonian. Our main result is that H is the closure of the restriction of the singular operator [Formula: see text] on an appropriate domain that shall be explicitly described. The symmetric differentiation [Formula: see text] is a generalization of the generator of the time shift, [Formula: see text] and [Formula: see text] are annihilation and creation operators and [Formula: see text] is the symmetric Dirac δ-function. In one dimension the symmetric differentiation might be used to establish a quantum stochastic calculus without Ito term.
ON TRACIAL DISTRIBUTIONS — A CONTRIBUTION TO THE HIDA THEORY
Authors: KALLIANPUR GOPINATH
Published: March 2005

Tracial distributions are defined as the elements of the dual of a countably Hilbertian space and on which a projective limit topology is defined. The connection of these distributions with Hida's generalized functions is discussed.
Distinct functional properties of native somatostatin receptor subtype 5 compared with subtype 2 in the regulation of ACTH release by corticotroph tumor cells
Authors: van der Hoek Joost , Waaijers Marlijn , van Koetsveld Peter M. , Sprij-Mooij Diana , Feelders Richard A. , Schmid Herbert A. , Schoeffter Philippe , Hoyer Daniel , Cervia Davide , Taylor John E. , Culler Michael D. , Lamberts Steven W. J. , Hofland Leo J.
Published: March 2005

In a series of human corticotroph adenomas, we recently found predominant mRNA expression of somatostatin (SS) receptor subtype 5 (sst5). After 72 h, the multiligand SS analog SOM230, which has a very high sst5binding affinity, but not Octreotide (OCT), significantly inhibited basal ACTH release. To further explore the role of sst5in the regulation of ACTH release, we conducted additional studies with mouse AtT-20 cells. SOM230 showed a 7-fold higher ligand binding affinity and a 19-fold higher potency in stimulating guanosine 5′- O-(3-thiotriphosphate) binding in AtT-20 cell membranes compared with OCT. SOM230 potently suppressed CRH-induced ACTH release, which was not affected by 48-h dexamethasone (DEX) pretreatment. However, DEX attenuated the inhibitory effects of OCT on ACTH release, whereas it increased the inhibitory potency of BIM-23268, an sst5-specific analog, on ACTH release. Quantitative PCR analysis showed that DEX lowered sst2A+2BmRNA expression significantly after 24 and 48 h, whereas sst5mRNA levels were not significantly affected by DEX treatment. Moreover, Scatchard analyses showed that DEX suppressed maximum binding capacity (Bmax) by 72% when125I-Tyr3-labeled OCT was used as radioligand, whereas Bmaxdeclined only by 17% when AtT-20 cells were treated with [125I-Tyr11]SS-14. These data suggest that the sst5protein, compared with sst2, is more resistant to glucocorticoids. Finally, after SS analog preincubation, compared with OCT both SOM230 and BIM-23268 showed a significantly higher inhibitory effect on CRH-induced ACTH release. In conclusion, our data support the concept that the sst5receptor might be a target for new therapeutic agents to treat Cushing’s disease.
Effects of sirolimus on mesangial cell cholesterol homeostasis: a novel mechanism for its action against lipid-mediated injury in renal allografts
Authors: Varghese Zac , Fernando Ray , Moorhead John F. , Powis Stephen H. , Ruan Xiong Z.
Published: March 2005

Lipoprotein abnormalities are present in a high proportion of renal transplant patients. It is accepted that dyslipidemia is associated with atherosclerosis and in the progression of renal disease. Lipid abnormalities may also play a significant role in the development of chronic allograft nephropathy. Sirolimus was found to have an antiatherosclerotic effect in the apolipoprotein E-knockout mice model of hyperlipidemia through its antiproliferative effects. As lipid-mediated renal injury is important in the pathogenesis of glomerulosclerosis which shares common pathogenic mechanisms with atherosclerosis, in this study we have tested the hypothesis that sirolimus prevents lipid-mediated renal injury through the modulation of cholesterol homeostasis of mesangial cells and its anti-inflammatory effects on macrophages. We demonstrated that sirolimus reduced lipid accumulation, as measured by oil red O staining in human mesangial cells (HMCs). Using real-time PCR, we screened the mRNA expression of lipoprotein receptors. Sirolimus significantly suppressed LDL and VLDL receptors and CD36 gene expression. It also increased cholesterol efflux from HMCs by increasing peroxisome proliferator-activated receptor-α (PPARα), PPARγ, liver X receptor-α, and ATP binding cassette A1 (ABCA1) gene expression. Sirolimus overrode the suppression of cholesterol efflux and ABCA1 gene expression induced by the inflammatory cytokine IL-1β. Furthermore, sirolimus significantly inhibited inflammatory cytokines IL-6 and TNF-α production in macrophages. These data suggest that sirolimus may prevent cellular cholesterol accumulation even in the presence of hyperlipidemia and inflammation, by regulating both cholesterol homeostasis and inflammatory responses.
Acute and chronic changes in cholesterol modulate Na-Picotransport activity in OK cells
Authors: Breusegem Sophia Y. , Halaihel Nabil , Inoue Makoto , Zajicek Hubert , Lederer Eleanor , Barry Nicholas P. , Sorribas Victor , Levi Moshe
Published: March 2005

We previously showed an inverse correlation between membrane cholesterol content and Na-Picotransport activity during the aging process and adaptation to alterations in dietary Piin the rat (Levi M, Jameson DM, and van der Meer BW. Am J Physiol Renal Fluid Electrolyte Physiol 256: F85–F94, 1989). The purpose of the present study was to determine whether alterations in cholesterol content per se modulate Na-Picotransport activity and apical membrane Na-Piprotein expression in opossum kidney (OK) cells. Acute cholesterol depletion achieved with β-methyl cyclodextrin (β-MCD) resulted in a significant increase in Na-Picotransport activity accompanied by a moderate increase in apical membrane Na-Piprotein abundance and no alteration of total cellular Na-Piprotein abundance. Conversely, acute cholesterol enrichment achieved with β-MCD/cholesterol resulted in a significant decrease in Na-Picotransport activity with a moderate decrease in apical membrane Na-Pi protein abundance and no change of the total cellular Na-Piprotein abundance. In contrast, chronic cholesterol depletion, achieved by growing cells in lipoprotein-deficient serum (LPDS), resulted in parallel and significant increases in Na-Picotransport activity and apical membrane and total cellular Na-Piprotein abundance. Cholesterol depletion also resulted in a significant increase in membrane lipid fluidity and alterations in lipid microdomains as determined by laurdan fluorescence spectroscopy and imaging. Chronic cholesterol enrichment, achieved by growing cells in LPDS followed by loading with low-density lipoprotein, resulted in parallel and significant decreases in Na-Picotransport activity and apical membrane and total cellular Na-Piprotein abundance. Our results indicate that in OK cells acute and chronic alterations in cholesterol content per se modulate Na-Picotransport activity by diverse mechanisms that also include significant interactions of Na-Piprotein with lipid microdomains.
Ischemia-induced cleavage of cadherins in NRK cells: evidence for a role of metalloproteinases
Authors: Covington Marisa D. , Bayless Kayla J. , Burghardt Robert C. , Davis George E. , Parrish Alan R.
Published: March 2005

Although ischemia has been shown to disrupt cell adhesion, the underlying molecular mechanism is unknown. In these studies, we adapted a model of ischemia-reperfusion to normal rat kidney (NRK) cells, examined disruption of the cadherin/catenin complex, and identified a role for matrix metalloproteinases (MMPs) in ischemia-induced cleavage of cadherins. In NRK cells, ischemia was induced by applying a thin layer of PBS solution supplemented with calcium and magnesium and a layer of mineral oil, which restricts exposure to oxygen. NRK cells exhibited extracellular 80-kDa and intracellular 40-kDa E-cadherin fragments after 4 h of ischemia, and at 6 h the expression of full-length E-cadherin decreased. While no fragments of N-cadherin, α-catenin, and γ-catenin were observed at any time point, the detectable levels of these proteins decreased during ischemia. Ischemia was detected by an increase in pimonidazole adducts, as well as an increase in glucose transporter-1 protein expression. Ischemia did not decrease cell number, but there was a decrease in ATP levels. In addition, there was no evidence of cleaved caspase 3 or 9 during 6 h of ischemia. The MMP inhibitors GM-6001 and TAPI-O inhibited cleavage and/or loss of E- and N-cadherin protein expression. Tissue inhibitors of metalloproteinases (TIMP)-3 and to a lesser extent TIMP-2, but not TIMP-1, inhibit ischemic cleavage and/or loss of E- and N-cadherin. These results demonstrate that ischemia induces a selective metalloproteinase-dependent cleavage of E-cadherin and decrease in N-cadherin that are associated with a disruption of junctional contacts.
Increased reactive oxygen species contribute to high NaCl-induced activation of the osmoregulatory transcription factor TonEBP/OREBP
Authors: Zhou Xiaoming , Ferraris Joan D. , Cai Qi , Agarwal Anupam , Burg Maurice B.
Published: March 2005

The signaling pathways leading to high NaCl-induced activation of the transcription factor tonicity-responsive enhancer binding protein/osmotic response element binding protein (TonEBP/OREBP) remain incompletely understood. High NaCl has been reported to produce oxidative stress. Reactive oxygen species (ROS), which are a component of oxidative stress, contribute to regulation of transcription factors. The present study was undertaken to test whether the high NaCl-induced increase in ROS contributes to tonicity-dependent activation of TonEBP/OREBP. Human embryonic kidney 293 cells were used as a model. We find that raising NaCl increases ROS, including superoxide. N-acetylcysteine (NAC), an antioxidant, and MnTBAP, an inhibitor of superoxide, reduce high NaCl-induced superoxide activity and suppress both high NaCl-induced increase in TonEBP/OREBP transcriptional activity and high NaCl-induced increase in expression of BGT1mRNA, a transcriptional target of TonEBP/OREBP. Catalase, which decomposes hydrogen peroxide, does not have these effects, whether applied exogenously or overexpressed within the cells. Furthermore, NAC and MnTBAP, but not catalase, blunt high NaCl-induced increase in TonEBP/OREBP transactivation. NG-monomethyl-l-arginine, a general inhibitor of nitric oxide synthase, has no significant effect on either high NaCl-induced increase in superoxide or TonEBP/OREBP transcriptional activity, suggesting that the effects of ROS do not involve nitric oxide. Ouabain, an inhibitor of Na-K-ATPase, attenuates high NaCl-induced superoxide activity and inhibits TonEBP/OREBP transcriptional activity. We conclude that the high NaCl-induced increase in ROS, including superoxide, contributes to activation of TonEBP/OREBP by increasing its transactivation.
Ventilatory long-term facilitation is greater in 1- vs. 2-mo-old awake rats
Authors: McGuire Michelle , Ling Liming
Published: March 2005

Respiratory long-term facilitation (LTF) declines in middle-aged vs. adult male rats. Chronic intermittent hypoxia (CIH; 5 min 11–12% O2/5 min air, 12 h/night, 7 nights) enhances LTF in adult rats. However, LTF in immature rats and the effect of early CIH are unevaluated. The present study compared LTF in 1- and 2-mo-old rats and examined the effect of neonatal CIH (initiated at 2 days after birth) on the LTF. Ventilatory LTF, elicited by 5 ( protocol 1) or 10 ( protocol 2) episodes of poikilocapnic hypoxia (5 min 12% O2/5 min air), was measured twice by plethysmography on the same male conscious rat when it was 1 and 2 mo old. In untreated (without CIH) rats, both resting ventilation (54.7 ± 0.6 vs. 43.0 ± 0.2 ml·100 g−1·min−1) and hypoxic ventilatory response (131 ± 4 vs. 66 ± 3% above baseline) were greater in 1- vs. 2-mo-old rats. Protocol 1 elicited LTF in 1-mo-old (12.5 ± 1.0% above baseline) but not 2-mo-old rats. Protocol 2 elicited a greater LTF in 1-mo-old (24.3 ± 0.8%) vs. 2-mo-old rats (18.2 ± 0.5%). In CIH-treated rats, protocol 1 also elicited LTF in 1-mo-old (13.1 ± 1.5%) but not 2-mo-old rats. Protocol 2 elicited LTF in both age groups, but LTF was enhanced by the CIH only in 1-mo-old rats (28.8 ± 0.9%). These results suggest that ventilatory LTF and hypoxic ventilatory response are greater in male rats shortly before their sexual maturity and that the neonatal CIH somewhat enhances ventilatory LTF ∼3 wk after CIH, but this enhancement does not last to adulthood.
Force sensing and generation in cell phases: analyses of complex functions
Authors: Döbereiner Hans-Günther , Dubin-Thaler Benjamin J. , Giannone Gregory , Sheetz Michael P.
Published: March 2005

Cellular morphology is determined by motility, force sensing, and force generation that must be finely controlled in a dynamic fashion. Contractile and extensile functions are integrated with the overall cytoskeleton, including linkages from the cytoplasmic cytoskeleton to the extracellular matrix and other cells by force sensing. During development, as cells differentiate, variations in protein expression levels result in morphological changes. There are two major explanations for motile behavior: either cellular motility depends in a continuous fashion on cell composition or it exhibits phases wherein only a few protein modules are activated locally for a given time. Indeed, in support of the latter model, the quantification of cell spreading and other motile activities shows multiple distinct modes of behavior, which we term “phases” because there exist abrupt transitions between them. Cells in suspension have a basal level of motility that enables them to probe their immediate environment. After contacting a matrix-coated surface, they rapidly transition to an activated spreading phase. After the development of a significant contact area, the cells contract repeatedly to determine the rigidity of the substrate and then develop force on matrix contacts. When cells are fully spread, extension activity is significantly decreased and focal complexes start to assemble near the cell periphery. For each of these phases, there are significant differences in protein activities, which correspond to differences in function. Thus overall morphological change of a tissue is driven by chemical signals and force-dependent activation of one or more motile phases in limited cell regions for defined periods.
Can Receptor Potentials Be Detected With Threshold Tracking in Rat Cutaneous Nociceptive Terminals?
Authors: Sauer S. K. , Weidner C. , Carr R. W. , Averbeck B. , Nesnidal U. , Reeh P. W. , Handwerker H. O.
Published: March 2005

Threshold tracking of individual polymodal C- and Aδ-fiber terminals was used to assess membrane potential changes induced by de- or hyperpolarizing stimuli in the isolated rat skin–nerve preparation. Constant current pulses were delivered (1 Hz) through a tungsten microelectrode inserted in the receptive field, and the current amplitude was controlled by feedback with a laboratory computer programmed to serially determine the electrical threshold using the method of limits. During threshold tracking, the receptive fields of the fibers were heated (32–46°C in 210 s) or superfused with modified synthetic interstitial fluid containing either 0, 20, 40, 50, or 60 mM [K+], phosphate buffer to pH 5.2 or 6.1, or bradykinin (BK, 10−8–10-5 M). High [K+]e decreased the current threshold for activation by 6–14% over 120 s, whereas K+-free superfusion augmented the threshold by >5%, and after some delay, also induced ongoing discharge in 60% of units. pH 6.1 and 5.2 caused an increase in threshold of 6 and 18%, respectively, and 30% of the fibers were excited by low pH, although the change in threshold of pH responsive and unresponsive fibers did not differ significantly, suggesting a general excitability decrease induced by protons. Heat stimulation increased the mean threshold and conduction velocity of the fibers tested and resulted in activity in 78% of units. Additionally, for these units, activation was preceded by a significant decrease in threshold compared with the tracked thresholds of fibers unresponsive to heat. Bradykinin also led to a significant threshold decrease before activation. In conclusion, the technique of threshold tracking proved suitable to assess changes in excitability resulting from receptor currents evoked by noxious heat and bradykinin in the terminal arborization of cutaneous nociceptors.
New fACEs to the Renin-Angiotensin System
Authors: Fleming Ingrid , Kohlstedt Karin , Busse Rudi
Published: March 2005

Inhibition of the angiotensin-converting enzyme (ACE) protects against the progression of several cardiovascular diseases. Recent evidence suggests that some of the beneficial effects of ACE inhibitors can be attributed to the activation of a distinct ACE signaling cascade rather than to the changes in angiotensin II and bradykinin levels. Moreover, at least one other ACE homolog (ACE2) plays a significant role in the regulation of heart and kidney function.
Genetic Diversity among the Arabs
Authors: Teebi Ahmad S. , Teebi Saeed A.
Published: March 2005

The Arabs in general are genetically diverse. Major factors that contributed to their diversity include the migrations of Semitic tribes from the Arabian Peninsula, the Islamic expansion in the 7th century AD, the Crusade wars and the recent migration dynamics. These events have resulted in the admixture of the original Arabs with other populations extending from east and south Asia to Europe and Africa. Their demographic features include high rates of consanguinity, a large family size and a rapid population growth. There is a high frequency of autosomal recessive disorders and increased frequencies of homozygosity for autosomal dominant traits, such as familial hypercholesterolemia and X-linked traits, such as glucose-6-phosphate dehydrogenase deficiency. The patterns of autosomal recessive disorders, including their mutations, may be different in various geographic locations within the Arab world. However, there are disorders that are specifically prevalent among the Arabs either uniformly or in certain locations. The Arab Genetic diseases include Bardet-Biedl syndrome, Meckel syndrome, autosomal recessive severe childhood muscular dystrophy, osteopetrosis and renal tubular acidosis, Sanjad-Sakati syndrome and others.
Genetic Contribution to High Neonatally Lethal Malformation Rate in the United Arab Emirates
Authors: Dawodu A. , Al-Gazali L. , Varady E. , Varghese M. , Nath K. , Rajan V.
Published: March 2005

Objectives: We examined the contribution of genetic disorders to congenital anomalies (CA) causing neonatal deaths in the Al Ain Medical District (AMD) in the United Arab Emirates (UAE) because of the high consanguineous marriage rate in the community. Methods: Charts of all neonatal deaths in the three perinatal units, which accounted for 99% of all births in AMD (1992–2000), were studied. Data regarding pregnancy, a family history including the level of parental consanguinity, the results of genetic evaluations and neonatal outcomes were recorded as part of an ongoing malformation surveillance system. Causes of death were based on clinical, laboratory and imaging findings. Results: Of the 508 neonates who died, 212 (42%) had CA, which were the leading cause of death. Forty-four percent of the CA were due to definite genetic disorders and 75% of these were single gene defects. Multisystem malformations were the commonest congenital malformations. Parental consanguinity was associated with a 2-fold increased risk of non-chromosomal multisystem malformations. Conclusions: Lethal malformations were the leading cause of neonatal deaths, and parental consanguinity was associated with an increased risk of autosomal recessive disorders. The results underscore the importance of genetic screening and counseling in strategies for further significant reductions in the neonatal mortality rate in the UAE.
Molecular Heterogeneity of Beta-Thalassemia in the United Arab Emirates
Authors: Baysal E.
Published: March 2005

Theβ-thalassemia alleles in 313 national patients of the United Arab Emirates (UAE) have been characterized using PCR-based DNA-diagnostic techniques including DNA sequencing. A total of 212 patients had homozygous β-thalassemia and the remaining 101 were compound heterozygotes. More than half of the patients were homozygous for the IVS-I-5 (G→C) mutation followed by the sickle cell gene. The latter accounted for 25% of the chromosomes. In terms of frequency, five β-thalassemia mutations; IVS-I-5 (G→C), βS, –25 bp del, Cd 8/9 (+G) and IVS-II-1 (G→A) accounted for 83% of the alleles. In addition, 427 expatriate patients were studied: 256 with homozygous β-thalassemia and 171 were compound heterozygotes. In both the UAE nationals and expatriates, the β-thalassemia mutations and their frequency followed a similar trend. Our results indicate that the frequency of β-globin gene defects including β-thalassemia, sickle cell gene (βS) and abnormal hemoglobins is significantly increased and poses a major public health problem in the UAE. The number of homozygous patients strongly suggests a high degree of consanguinity among the UAE nationals. With 50 different β-thalassemia alleles, UAE is arguably the most heterogeneous population in the world. The diversity of these mutations reflects the historical admixture of genes and their migration from different areas in the region. Our data strongly suggest the need for a comprehensive thalassemia control program and provides a basis for population screening, genetic counseling and prenatal diagnosis.
Following the Rules: Why Small Groups of Tamarins Do Not Reconcile Conflicts
Authors: Schaffner Colleen M. , Aureli Filippo , Caine Nancy G.
Published: March 2005

Reconciliation is the post-conflict friendly reunion between opponents. A series of conditions and rules in order for reconciliation to take place has been recently proposed. One critical condition is that the relationship between opponents must be disrupted. We tested this condition using post-conflict and matched-control observations on 4 small groups of tamarins (Saguinus labiatus). Our previous lack of evidence for reconciliation was confirmed. No post-conflict relationship damage was therefore expected. We found evidence that relationships were disturbed following conflicts over food but, as in other primates, no evidence for reconciliation following such conflicts was found. For non-food-related conflicts there was no evidence that relationships were disturbed, as opponents were in close proximity to each other and resumed the exact same activity as frequently in the post-conflict observations as they did in the matched-control observations. We conclude that ‘everyday’ aggression may not disrupt the relationships among individuals from the same family group and therefore reconciliation is not needed.
Red Colobus as Prey: The Leaping Habits of Five Sympatric Old World Monkeys
Authors: Stern Michael , Goldstone Rebecca
Published: March 2005

This study explored the leaping habits of five sympatric Old World monkeys (Colobus badius, Colobus guereza, Cercopithecus ascanius, Cercopithecus mitis and Cercocebus albigena) in an attempt to determine why chimpanzees prefer to hunt red colobus. We videotaped the leaps of the monkeys for 3 months in Uganda’s Kibale National Park. Data were collected on leap preparation time as well as several other variables of the leaps. The leap preparation time of red colobus was found to be about double that of the other species studied. This difference is a likely reason why red colobus represent the preferred prey of chimpanzees. The hypothesis that red colobus spend more time in isolated trees than do other species was not supported.
Accumulation of Metals and Minerals from Phosphate Binders
Authors: Molony Donald A. , Murthy Bhamidipati
Published: March 2005

Metals and minerals that depend on renal clearance may accumulate to toxic levels in patients with marginal kidney function. Toxicities of aluminum-based phosphate binders became apparent ∼25 years ago. Nephrologists now recognize cardiovascular calcification may follow use of calcium-based phosphate binders. Five lessons can be learned: (1)safety must not be assumed in absence of data; (2) all evidence for causal linkage of toxicities from therapeutics must be considered, including animal data; (3) clinical trials are unlikely to reveal the spectrum of problems from long-term drug exposure; (4) complications can remain unrecognized until late in post-introduction surveillance; (5) minerals important for normal function can be toxic with excess accumulation. Introduction of new agents necessitates caution – it is difficult to change practice once a therapeutic is commonplace. Lessons learned about hazards of past phosphate binders must be applied judiciously when evaluating long-term risks/safety of novel metal-based binders such as lanthanum carbonate.
Phase Resetting of Arterial Vasomotion by Burst Stimulation of Perivascular Nerves
Authors: Borovik Anatoly , Golubinskaya Veronika , Tarasova Olga , Aalkjaer Christian , Nilsson Holger
Published: March 2005

Arteries display cyclic diameter variations, vasomotion. In vivo, these rhythmic contractions are modulated by the influence of sympathetic nerves. In this study, we investigated the effect of burst stimulation of intramural nerves in vitro on the vasomotion of rat mesenteric small arteries. Vessels were mounted for isometric force measurement. After initiation of vasomotion with noradrenaline (0.5–2 µM), periarterial sympathetic nerves were stimulated electrically (10 impulses at 20 Hz) at approximately half-minute intervals. With a delay of 2–3 s, a neurogenic burst caused a brief contraction of the vascular smooth muscle and altered the period of the current vasomotion cycle. The effect on amplitude decayed rapidly and was practically not apparent in the next vasomotion cycle after the burst. With respect to period, stimulation at increasing intervals from the trough in force of vasomotion caused gradual prolongation of the cycle until a critical interval was reached, after which cycle duration was reduced instead. Since subsequent cycles were not affected, a change in phase remained. When two segments of oscillating arteries were mounted in a two-vessel myograph, simultaneously applied bursts of impulses synchronized their oscillation. The data suggest that changes in neural activity are able to make different vessels oscillate in phase, thereby coordinating vasomotion in different parts of the vascular tree, possibly explaining the synchronicity of vasomotion in different vascular beds that can be observed in vivo.
The Triggering Procedure of the International Criminal Court, Procedural Treatment of the Principle of Complementarity, and the Role of Office of the Prosecutor
Authors: Olásolo Héctor
Published: March 2005

This article addresses the most fundamental procedural issues arising from Arts. 13, 14, 15, 18 and 53(1), (2) and (4) of the ICC Statute (hereinafter “the Rome Statute” or “RS”). It first analyses the reasons why the proceedings provided for in those articles constitute, referred to in this article as “Triggering Procedure”, within the complex procedural system provided for in the ICC Statute, an autonomous procedure whose object, parties and proceedings are perfectly distinguishable from the object, parties and proceedings of the Criminal and Civil Procedures. Once the relationship between the Triggering Procedure and the Criminal and Civil Procedures is introduced, the article analyses the procedural treatment of the principle of complementarity in the different procedures provided for in the ICC Statute. Finally, the last part of the article brie fly addresses the key role of the Of fice of the Prosecutor in the Triggering Procedure, and the duties imposed upon the competent Chamber of the Court to control, propio motu or at the request of a party to the proceedings, that the Of fice of the Prosecutor is acting within the powers granted to it by the RS and fully respecting the substantive and procedural standards set out by the RS.
TMB-Hunt: An amino acid composition based method to screen proteomes for beta-barrel transmembrane proteins
Authors: Garrow Andrew G , Agnew Alison , Westhead David R
Published: March 2005

Background

Beta-barrel transmembrane (bbtm) proteins are a functionally important and diverse group of proteins expressed in the outer membranes of bacteria (both gram negative and acid fast gram positive), mitochondria and chloroplasts. Despite recent publications describing reasonable levels of accuracy for discriminating between bbtm proteins and other proteins, screening of entire genomes remains troublesome as these molecules only constitute a small fraction of the sequences screened. Therefore, novel methods are still required capable of detecting new families of bbtm protein in diverse genomes.

Results

We present TMB-Hunt, a program that uses a k-Nearest Neighbour (k-NN) algorithm to discriminate between bbtm and non-bbtm proteins on the basis of their amino acid composition. By including differentially weighted amino acids, evolutionary information and by calibrating the scoring, an accuracy of 92.5% was achieved, with 91% sensitivity and 93.8% positive predictive value (PPV), using a rigorous cross-validation procedure.

A major advantage of this approach is that because it does not rely on beta-strand detection, it does not require resolved structures and thus larger, more representative, training sets could be used. It is therefore believed that this approach will be invaluable in complementing other, physicochemical and homology based methods. This was demonstrated by the correct reassignment of a number of proteins which other predictors failed to classify. We have used the algorithm to screen several genomes and have discussed our findings.

Conclusion

TMB-Hunt achieves a prediction accuracy level better than other approaches published to date. Results were significantly enhanced by use of evolutionary information and a system for calibrating k-NN scoring. Because the program uses a distinct approach to that of other discriminators and thus suffers different liabilities, we believe it will make a significant contribution to the development of a consensus approach for bbtm protein detection.
A dual fluorescent multiprobe assay for prion protein genotyping in sheep
Authors: Van Poucke Mario , Vandesompele Jo , Mattheeuws Marc , Van Zeveren Alex , Peelman Luc J
Published: March 2005

Background

Scrapie and BSE belong to a group of fatal, transmissible, neurodegenerative diseases called TSE. In order to minimize the risk of natural scrapie and presumed natural BSE in sheep, breeding programmes towards TSE resistance are conducted in many countries based on resistance rendering PRNP polymorphisms at codons 136 (A/V), 154 (R/H) and 171 (R/H/Q). Therefore, a reliable, fast and cost-effective method for routine PRNP genotyping in sheep, applicable in standard equipped molecular genetic laboratories, will be a vital instrument to fulfill the need of genotyping hundreds or thousands of sheep.

Methods

A dual fluorescent multiprobe assay consisting of 2 closed tube PCR reactions containing respectively 4 and 3 dual-labelled fluorescent ASO probes for the detection in real-time of the 7 allelic variants of sheep PRNP mentioned above.

Results

The assay is succesfully performed using unpurified DNA as a template for PCR, without any post-PCR manipulations and with semi-automatic determination of the PRNP genotypes. The performance of the assay was confirmed via PCR-RFLP and sequencing in a cross-validation study with 50 sheep.

Conclusions

We report the development and validation of a robust, reliable and reproducible method for PRNP genotyping of a few to many sheep samples in a fast, simple and cost-effective way, applicable in standard equipped molecular genetic laboratories. The described primer/probe design strategy can also be applied for the detection of other polymorphisms or disease causing mutations.
Public access defibrillation: Suppression of 16.7 Hz interference generated by the power supply of the railway systems
Authors: Christov Ivaylo I , Iliev Georgi L
Published: March 2005

Background

A specific problem using the public access defibrillators (PADs) arises at the railway stations. Some countries as Germany, Austria, Switzerland, Norway and Sweden are using AC railroad net power-supply system with rated 16.7 Hz frequency modulated from 15.69 Hz to 17.36 Hz. The power supply frequency contaminates the electrocardiogram (ECG). It is difficult to be suppressed or eliminated due to the fact that it considerably overlaps the frequency spectra of the ECG. The interference impedes the automated decision of the PADs whether a patient should be (or should not be) shocked.

The aim of this study is the suppression of the 16.7 Hz interference generated by the power supply of the railway systems.

Methods

Software solution using adaptive filtering method was proposed for 16.7 Hz interference suppression. The optimal performance of the filter is achieved, embedding a reference channel in the PADs to record the interference. The method was tested with ECGs from AHA database.

Results

The method was tested with patients of normal sinus rhythms, symptoms of tachycardia and ventricular fibrillation. Simulated interference with frequency modulation from 15.69 Hz to 17.36 Hz changing at a rate of 2% per second was added to the ECGs, and then processed by the suggested adaptive filtering. The method totally suppresses the noise with no visible distortions of the original signals.

Conclusion

The proposed adaptive filter for noise suppression generated by the power supply of the railway systems has a simple structure requiring a low level of computational resources, but a good reference signal as well.
Localization of the immunodominant region on human thyroid peroxidase in autoimmune thyroid diseases: an update
Authors: Bresson Damien , Rebuffat Sandra A , Péraldi-Roux Sylvie
Published: March 2005

Recent studies in the field of autoimmune thyroid diseases have largely focused on the delineation of B-cell auto-epitopes recognized by the main autoantigens to improve our understanding of how these molecules are seen by the immune system. Among these autoantigens which are targeted by autoantibodies during the development of autoimmune thyroid diseases, thyroid peroxidase is a major player. Indeed, high amounts of anti-thyroid peroxidase autoantibodies are found in the sera of patients suffering from Graves' disease and Hashimoto's thyroiditis, respectively hyper and hypothyroidism. Since anti-thyroid peroxidase autoantibodies from patients'sera mainly recognize a discontinuous immunodominant region on thyroid peroxidase and due to the complexity of the three dimensional structure of human thyroid peroxidase, numerous investigations have been necessary to closely localize this immunodominant region. The aim of the present review is to summarize the current knowledge regarding the localization of the immunodominant region recognized by human thyroid peroxidase-specific autoantibodies generated during the development of autoimmune thyroid diseases.
Bacteriophages: The viruses for all seasons of molecular biology
Authors: Karam Jim D
Published: March 2005

Bacteriophage research continues to break new ground in our understanding of the basic molecular mechanisms of gene action and biological structure. The abundance of bacteriophages in nature and the diversity of their genomes are two reasons why phage research brims with excitement. The pages of Virology Journal will reflect the excitement of the "New Phage Biology."
Contribution of transcriptional regulation to natural variations in Arabidopsis
Authors: Chen Wenqiong J , Chang Sherman H , Hudson Matthew E , Kwan Wai-King , Li Jingqiu , Estes Bram , Knoll Daniel , Shi Liang , Zhu Tong
Published: March 2005

Background

Genetic control of gene transcription is a key component in genome evolution. To understand the transcriptional basis of natural variation, we have studied genome-wide variations in transcription and characterized the genetic variations in regulatory elements among Arabidopsis accessions.

Results

Among five accessions (Col-0, C24, Ler, WS-2, and NO-0) 7,508 probe sets with no detectable genomic sequence variations were identified on the basis of the comparative genomic hybridization to the Arabidopsis GeneChip microarray, and used for accession-specific transcriptome analysis. Two-way ANOVA analysis has identified 60 genes whose mRNA levels differed in different accession backgrounds in an organ-dependent manner. Most of these genes were involved in stress responses and late stages of plant development, such as seed development. Correlation analysis of expression patterns of these 7,508 genes between pairs of accessions identified a group of 65 highly plastic genes with distinct expression patterns in each accession.

Conclusion

Genes that show substantial genetic variation in mRNA level are those with functions in signal transduction, transcription and stress response, suggesting the existence of variations in the regulatory mechanisms for these genes among different accessions. This is in contrast to those genes with significant polymorphisms in the coding regions identified by genomic hybridization, which include genes encoding transposon-related proteins, kinases and disease-resistance proteins. While relatively fewer sequence variations were detected on average in the coding regions of these genes, a number of differences were identified from the upstream regions, several of which alter potential cis-regulatory elements. Our results suggest that nucleotide polymorphisms in regulatory elements of genes encoding controlling factors could be primary targets of natural selection and a driving force behind the evolution of Arabidopsis accessions.
Pilot Anopheles gambiaefull-length cDNA study: sequencing and initial characterization of 35,575 clones
Authors: Gomez Shawn M , Eiglmeier Karin , Segurens Beatrice , Dehoux Pierre , Couloux Arnaud , Scarpelli Claude , Wincker Patrick , Weissenbach Jean , Brey Paul T , Roth Charles W
Published: March 2005

We describe the preliminary analysis of over 35,000 clones from a full-length enriched cDNA library from the malaria mosquito vector Anopheles gambiae. The clones define nearly 3,700 genes, of which around 2,600 significantly improve current gene definitions. An additional 17% of the genes were not previously annotated, suggesting that an equal percentage may be missing from the current Anopheles genome annotation.