bluuebunny/crossref_metadata_2025 huggingface dataset:
Endocytosis of the Nipah Virus Glycoproteins
Authors: Vogt Carola , Eickmann Markus , Diederich Sandra , Moll Markus , Maisner Andrea
Published: February 2005

Nipah virus
(NiV), a highly pathogenic member of the family
Paramyxoviridae
, encodes the surface glycoproteins F and G. Since internalization of the NiV envelope proteins from the cell surface might be of functional importance for viral pathogenesis either by regulating cytopathogenicity or by modulating recognition of infected cells by the immune system, we analyzed the endocytosis of the NiV F and G proteins. Interestingly, we found both glycoproteins to be internalized in infected and transfected cells. As endocytosis is normally mediated by tyrosine- or dileucine-dependent signals in the cytoplasmic tails of transmembrane proteins, all potential internalization signals in the NiV glycoproteins were mutated. Whereas the G protein appeared to be constitutively internalized with the bulk flow during membrane turnover, uptake of the F protein was found to be signal mediated. F endocytosis clearly depended on a membrane-proximal YXXΦ motif and was found to be of functional importance for the biological activity of the protein.
Splicing of Rhesus Rhadinovirus R15 and ORF74 Bicistronic Transcripts during Lytic Infection and Analysis of Effects on Production of vCD200 and vGPCR
Authors: Pratt Carly L. , Estep Ryan D. , Wong Scott W.
Published: February 2005

Rhesus macaque rhadinovirus (RRV) is the rhesus macaque homologue of human herpesvirus 8 (HHV-8). Here we examine expression of RRV R15 and ORF74, homologues of K14 and ORF74 of HHV-8, respectively. As in HHV-8, transcripts encoding RRV R15 and ORF74 are bicistronic. However, unlike what has been suggested for HHV-8, RRV R15- and ORF74-encoding transcripts are expressed late during lytic infection and undergo unique splicing events that result in the production of transcripts capable of encoding vGPCR, as well as membrane-associated and secreted forms of vCD200. The alternative splicing for vCD200 has implications for viral pathogenesis.
ADAPTIVE CONTROL OF HYBRIDIZATION NOISE IN DNA SEQUENCING-BY-HYBRIDIZATION
Authors: LEONG HON-WAI , PREPARATA FRANCO P. , SUNG WING-KIN , WILLY HUGO
Published: February 2005

We consider the problem of sequence reconstruction in sequencing-by-hybridization in the presence of spectrum errors. As suggested by intuition, and reported in the literature, false-negatives (i.e., missing spectrum probes) are by far the leading cause of reconstruction failures. In a recent paper we have described an algorithm, called "threshold-θ", designed to recover from false negatives. This algorithm is based on overcompensating for missing extensions by allowing larger reconstruction subtrees. We demonstrated, both analytically and with simulations, the increasing effectiveness of the approach as the parameter θ grows, but also pointed out that for larger error rates the size of the extension trees translates into an unacceptable computational burden. To obviate this shortcoming, in this paper we propose an adaptive approach which is both effective and efficient. Effective, because for a fixed value of θ it performs as well as its single-threshold counterpart, efficient because it exhibits substantial speed-ups over it. The idea is that, for moderate error rates a small fraction of the target sequence can be involved in error recovery; thus, expectedly the remainder of the sequence is reconstructible by the standard noiseless algorithm, with the provision to switch to operation with increasingly higher thresholds after detecting failure. This policy generates interesting and complex interplays between fooling probes and false negatives. These phenomena are carefully analyzed for random sequences and the results are found to be in excellent agreement with the simulations. In addition, the experimental algorithmic speed-ups of the multithreshold approach are explained in terms of the interaction amongst the different threshold regimes.
Subcloning, localization, and expression of the rat intestinal sodium-hydrogen exchanger isoform 8
Authors: Xu Hua , Chen Rongji , Ghishan Fayez K.
Published: February 2005

Apically expressed intestinal and renal sodium-hydrogen exchangers (NHEs) play a major role in Na+ absorption. Our previous studies on NHE ontogeny have shown that NHE-2 and NHE-3 are expressed at very low levels in young animals. Furthermore, single and/or double NHE-2 and NHE-3 knockout mice display no obvious abnormalities before weaning. These observations suggest that other transporter(s) may be involved in intestinal Na+ absorption during early life. The present studies were designed to clone the novel rat intestinal NHE-8 cDNA and to decipher the NHE-8 protein localization and gene expression pattern during different developmental stages. The rat NHE-8 cDNA has 2,160 bp and encodes a 575-amino acid protein. An antibody against NHE-8 protein was developed. Immunohistochemistry staining indicated apical localization of NHE-8 protein in rat intestinal epithelial cells. The apical localization of NHE-8 was also confirmed by its presence in brush-border membrane and its absence in basolateral membrane preparations. Northern blotting utilizing a NHE-8-specific probe demonstrated higher NHE-8 mRNA expression in young animals compared with adult animals. Western blot analysis revealed a similar pattern. Tissue distribution with multiple human tissue RNA blot showed that NHE-8 was expressed in multiple tissues including the gastrointestinal tract. In conclusion, we have cloned the full-length NHE-8 cDNA from rat intestine and further showed its apical localization in intestinal epithelial cells. We have also shown that NHE-8 gene expression and protein expression were regulated during ontogeny. Our data suggests that NHE-8 may play an important role in intestinal Na+ absorption during early life.
Perinatal hyperoxia for 14 days increases nerve conduction time and the acute unitary response to hypoxia of rat carotid body chemoreceptors
Authors: Donnelly David F. , Kim Insook , Carle Claire , Carroll John L.
Published: February 2005

Hyperoxia in the immediate perinatal period, but not in adult life, is associated with a life-long impairment of the ventilatory response to acute hypoxia. This effect is attributed to a functional impairment of peripheral chemoreceptors, including a reduction in the number of chemoreceptor afferent fibers and a reduction in “whole nerve” afferent activity. The purpose of the present study was to assess the activity levels of single chemoreceptor units in the immediate posthyperoxic period to determine whether functional impairment extended to single chemoreceptor units and whether the impairment was only induced by hyperoxia exposure in the immediate postnatal period. Two groups of rat pups were exposed to 60% inspired O2 fraction for 2 wk at ages 0–14 days and 14–28 days, at which time single-unit activities were isolated and recorded in vitro. Compared with control pups, hyperoxia-treated pups had a 10-fold reduction in baseline (normoxia) spiking activity. Peak unit responses to 12, 5, and 0% O2 were reduced and nerve conduction time was significantly slower in both hyperoxia-treated groups compared with control groups. We conclude that 1) hyperoxia greatly reduces single-unit chemoreceptor activities during normoxia and acute hypoxia, 2) the treatment effect is not limited to the immediate newborn period, and 3) at least part of the impairment may be due to changes in the afferent axonal excitability.
Mechanoelectrical excitation by fluid jets in monolayers of cultured cardiac myocytes
Authors: Kong Chae-Ryon , Bursac Nenad , Tung Leslie
Published: February 2005

Although the prevailing view of mechanoelectric feedback (MEF) in the heart is in terms of longitudinal cell stretch, other mechanical forces are considerable during the cardiac cycle, including intramyocardial pressure and shear stress. Their contribution to MEF is largely unknown. In this study, mechanical stimuli in the form of localized fluid jet pulses were applied to neonatal rat ventricular cells cultured as confluent monolayers. Such pulses result in pressure and shear stresses (but not longitudinal stretch) in the monolayer at the point of impingement. The goal was to determine whether these mechanical stimuli can trigger excitation, initiate a propagated wave, and induce reentry. Cells were stained with the voltage-sensitive dye RH237, and multi-site optical mapping was used to record the spread of electrical activity in isotropic and anisotropic monolayers. Pulses (10 ms) with velocities ranging from 0.3 to 1.8 m/s were applied from a 0.4-mm diameter nozzle located 1 mm above the cell monolayer. Fluid jet pulses resulted in circular wavefronts that propagated radially from the stimulus site. The likelihood for mechanical stimulation was quantified as an average stimulus success rate (ASSR). ASSR increased with jet amplitude and time waited between stimuli and decreased with the application of gadolinium and streptomycin, blockers of stretch-activated channels, but not with nifedipine, a blocker of the L-type Ca channel. Absence of cellular injury was confirmed by smooth propagation maps and propidium iodide stains. In rare instances, the mechanical pulse resulted in the induction of reentrant activity. We conclude that mechanical stimuli other than stretch can evoke action potentials, propagated activity, and reentrant arrhythmia in two-dimensional sheets of cardiac cells.
Extracellular water: greater expansion with age in African Americans
Authors: Silva Analiza M. , Wang Jack , Pierson Richard N. , Wang ZiMian , Heymsfield Steven B. , Sardinha Luis B. , Heshka Stanley
Published: February 2005

Aging is associated with the onset of chronic diseases that lead to pathological expansion of the extracellular water (ECW) compartment. Healthy aging, in the absence of disease, is also reportedly accompanied by a relative expansion of the ECW compartment, although the studies on which this observation is based are few in number, applied different ECW measurement methods, included small ethnically homogeneous subject samples, and failed to adjust ECW for non-age-related influencing factors. The aim of the current study was to examine, in a large ( n = 1,538) ethnically diverse [African American (AA), Asian, Caucasian, Hispanic] subject group the cross-sectional relationships between ECW and age after controlling first for other potential factors that may influence fluid distribution. ECW and intracellular water (ICW) were derived from measured total body water (isotope dilution) and potassium (40K whole body counting). The cross-sectional relationships between ECW, ICW, and ECW/ICW (E/I), and age were developed using multiple regression modelling methods. Body weight, weight squared, height, age, sex, race, and interactions were all significant ECW predictors. The slope of the observed race × age interaction was significantly greater in AA (β = 0.0005, P = 0.005) than in the three other race groups. Race, sex, and age differences in fluid distribution persisted after adjusting for body composition in a subgroup ( n = 994) with dual-energy X-ray absorptiometry lean soft tissue and fat measurements. A relative ECW expansion (i.e., E/I) was present with greater age in most sex-race groups, although the effect was not significantly larger in AA males ( P > 0.05) compared with the other race groups, except Asians ( P < 0.05). For females, a larger E/I-age effect was found in AA compared with the other race groups, but only the comparison against Hispanics was significant ( P < 0.05). The ECW compartment and E/I are thus variably larger, according to race, in healthy older subjects independent of sex, lean soft tissue, and fat mass.
Computational Model of Electrically Coupled, Intrinsically Distinct Pacemaker Neurons
Authors: Soto-Treviño Cristina , Rabbah Pascale , Marder Eve , Nadim Farzan
Published: February 2005

Electrical coupling between neurons with similar properties is often studied. Nonetheless, the role of electrical coupling between neurons with widely different intrinsic properties also occurs, but is less well understood. Inspired by the pacemaker group of the crustacean pyloric network, we developed a multicompartment, conductance-based model of a small network of intrinsically distinct, electrically coupled neurons. In the pyloric network, a small intrinsically bursting neuron, through gap junctions, drives 2 larger, tonically spiking neurons to reliably burst in-phase with it. Each model neuron has 2 compartments, one responsible for spike generation and the other for producing a slow, large-amplitude oscillation. We illustrate how these compartments interact and determine the dynamics of the model neurons. Our model captures the dynamic oscillation range measured from the isolated and coupled biological neurons. At the network level, we explore the range of coupling strengths for which synchronous bursting oscillations are possible. The spatial segregation of ionic currents significantly enhances the ability of the 2 neurons to burst synchronously, and the oscillation range of the model pacemaker network depends not only on the strength of the electrical synapse but also on the identity of the neuron receiving inputs. We also compare the activity of the electrically coupled, distinct neurons with that of a network of coupled identical bursting neurons. For small to moderate coupling strengths, the network of identical elements, when receiving asymmetrical inputs, can have a smaller dynamic range of oscillation than that of its constituent neurons in isolation.
Vestibular Perception and Action Employ Qualitatively Different Mechanisms. I. Frequency Response of VOR and Perceptual Responses DuringTranslationandTilt
Authors: Merfeld Daniel M. , Park Sukyung , Gianna-Poulin Claire , Black F. Owen , Wood Scott
Published: February 2005

To investigate the neural mechanisms that humans use to process the ambiguous force measured by the otolith organs, we measured vestibuloocular reflexes (VORs) and perceptions of tilt and translation. One primary goal was to determine if the same, or different, mechanisms contribute to vestibular perception and action. We used motion paradigms that provided identical sinusoidal inter-aural otolith cues across a broad frequency range. We accomplished this by sinusoidally tilting (20°, 0.005–0.7 Hz) subjects in roll about an earth-horizontal, head-centered, rotation axis (“ Tilt”) or sinusoidally accelerating (3.3 m/s2, 0.005–0.7 Hz) subjects along their inter-aural axis (“ Translation”). While identical inter-aural otolith cues were provided by these motion paradigms, the canal cues were substantially different because roll rotations were present during Tilt but not during Translation. We found that perception was dependent on canal cues because the reported perceptions of both roll tilt and inter-aural translation were substantially different during Translation and Tilt. These findings match internal model predictions that rotational cues from the canals influence the neural processing of otolith cues. We also found horizontal translational VORs at frequencies >0.2 Hz during both Translation and Tilt. These responses were dependent on otolith cues and match simple filtering predictions that translational VORs include contributions via simple high-pass filtering of otolith cues. More generally, these findings demonstrate that internal models govern human vestibular “perception” across a broad range of frequencies and that simple high-pass filters contribute to human horizontal translational VORs (“action”) at frequencies above ∼0.2 Hz.
Vestibular Perception and Action Employ Qualitatively Different Mechanisms. II. VOR and Perceptual Responses During CombinedTilt&Translation
Authors: Merfeld Daniel M. , Park Sukyung , Gianna-Poulin Claire , Black F. Owen , Wood Scott
Published: February 2005

II. VOR and perceptual responses during combined Tilt&Translation. To compare and contrast the neural mechanisms that contribute to vestibular perception and action, we measured vestibuloocular reflexes (VOR) and perceptions of tilt and translation. We took advantage of the well-known ambiguity that the otolith organs respond to both linear acceleration and tilt with respect to gravity and investigated the mechanisms by which this ambiguity is resolved. A new motion paradigm that combined roll tilt with inter-aural translation (“ Tilt&Translation”) was used; subjects were sinusoidally (0.8 Hz) roll tilted but with their ears above or below the rotation axis. This paradigm provided sinusoidal roll canal cues that were the same across trials while providing otolith cues that varied linearly with ear position relative to the earth-horizontal rotation axis. We found that perceived tilt and translation depended on canal cues, with substantial roll tilt and inter-aural translation perceptions reported even when the otolith organs measured no inter-aural force. These findings match internal model predictions that rotational cues from the canals influence the neural processing of otolith cues. We also found horizontal translational VORs that varied linearly with radius; a minimal response was measured when the otolith organs transduced little or no inter-aural force. Hence, the horizontal translational VOR was dependent on otolith cues but independent of canal cues. These findings match predictions that translational VORs are elicited by simple filtering of otolith signals. We conclude that internal models govern human perception of tilt and translation at 0.8 Hz and that high-pass filtering governs the human translational VOR at this same frequency.
Effects of GABA Receptor Antagonists on Retinal Glycine Receptors and on Homomeric Glycine Receptor Alpha Subunits
Authors: Wang Peiyuan , Slaughter Malcolm M.
Published: February 2005

Glycinergic and GABAergic inhibition are juxtaposed at one retinal synaptic layer yet likely perform different functions. These functions have usually been evaluated using receptor antagonists. In examining retinal glycine receptors, we were surprised to find that commonly used concentrations of GABA antagonists blocked significant fractions of the glycine current. In retinal amacrine and ganglion cells, the competitive GABAA receptor antagonists (bicuculline and SR95531) were also competitive GlyR antagonists. Picrotoxinin produced a noncompetitive inhibition of retinal GlyRs. [1,2,5,6-tetrahydropyridine-4-yl] methylphosphinic acid, the GABACR antagonist, did not inhibit glycine receptors. All three GABAA receptor antagonists were competitive inhibitors of homomeric α1 or α2 GlyRs expressed in human embryonic kidney cells (HEK293) cells. Interestingly, bicuculline was much more effective at α2 GlyRs and might be used to separate glycine receptor subtypes. Thus commonly used concentrations of GABA antagonists do not unambiguously differentiate GABA and glycine pathways. Picrotoxinin inhibition of GABAC receptors requires two amino acids in the second transmembrane region (TM2): 2′ serine and 6′ threonine. Although TM2 regions in GABA and glycine receptors are highly homologous, neither 2′ serine nor 6′ threonine is essential for picrotoxinin sensitivity in glycine receptors.
Oxidized Phospholipids Trigger Atherogenic Inflammation in Murine Arteries
Authors: Furnkranz Alexander , Schober Andreas , Bochkov Valery N. , Bashtrykov Pavel , Kronke Gerhard , Kadl Alexandra , Binder Bernd R. , Weber Christian , Leitinger Norbert
Published: February 2005

Objective—

Lipoprotein-derived phospholipid oxidation products have been implicated as candidate triggers of the inflammatory process in atherosclerosis. However, in vivo evidence regarding the impact of oxidized phospholipids on the artery wall thus far has been elusive. Therefore, the aim of this study was to investigate if structurally defined oxidized phospholipids induce expression of atherogenic chemokines and monocyte adhesion in intact murine arteries.

Methods and Results—

To model the accumulation of oxidized phospholipids in the arterial wall, oxidized 1-palmitoyl-2-arachidonoyl-
sn
-3-glycero-phosphorylcholine (OxPAPC) was topically applied to carotid arteries in mice using pluronic gel. Using quantitative reverse-transcriptase polymerase chain reaction (PCR) and immunohistochemistry, we show that OxPAPC induced a set of atherosclerosis-related genes, including monocyte chemotactic protein 1 (MCP-1) and keratinocyte-derived chemokine (KC), tissue factor (TF), interleukin 6 (IL-6), heme oxygenase 1 (HO-1), and early growth response 1 (EGR-1). OxPAPC-regulated chemokines were also expressed in atherosclerotic lesions of apolipoprotein E-deficient (ApoE
−/−
) mice. In isolated perfused carotid arteries, OxPAPC triggered rolling and firm adhesion of monocytes in a P-selectin and KC-dependent manner.

Conclusion—

Oxidized phospholipids contribute to vascular inflammation in murine arteries in vivo, initiating atherogenic chemokine expression that leads to monocyte adhesion; therefore, they can be regarded as triggers of the inflammatory process in atherosclerosis.
Meta-Analysis
Authors: Briggs Derek C.
Published: February 2005

This article raises some questions about the usefulness of meta-analysis as a means of reviewing quantitative research in the social sciences. When a meta-analytic model for SAT coaching is used to predict results from future studies, the amount of prediction error is quite large. Interpretations of meta-analytic regressions and quantifications of program and study characteristics are shown to be equivocal. The match between the assumptions of the meta-analytic model and the data from SAT coaching studies is not good, making statistical inferences problematic. Researcher subjectivity is no less problematic in the context of a meta-analysis than in a narrative review.
Reporting quality of randomized trials in the diet and exercise literature for weight loss
Authors: Gibson Cheryl A , Kirk Erik P , LeCheminant James D , Bailey Bruce W , Huang Guoyuan , Donnelly Joseph E
Published: February 2005

Background

To adequately assess individual studies and synthesize quantitative research on weight loss studies, transparent reporting of data is required. The authors examined the reporting quality of randomized trials in the weight loss literature, focusing exclusively on subject characteristics as they relate to enrollment, allocation, and follow-up.

Methods

An extensive literature review, which included a computerized search of the MEDLINE database, manual searches of bibliographic references, and cross-referencing of 92 review articles was conducted. A checklist, based on CONSORT recommendations, was used to collect information on whether or not authors reported age, gender, co-morbid disease, medication use, race/ethnicity, and postmenopausal status. Also tracked was whether or not initial and final sample size was reported and stratified by gender.

Results

Of 604 possible articles, 231 articles met eligibility criteria. Important subject characteristics were not reported as the following breakdown indicates: age (11%), gender (4%), race/ethnicity (86%), co-morbid disease states (34%), and medication use (92%). Additionally, 21% of articles failed to report initial sample size by gender while 69% neglected to report final sample size by gender.

Conclusion

Inadequate reporting can create difficulties with interpretation and can lead to biased results receiving false credibility. The quality of reporting for weight loss studies needs considerable improvement.
The Bosnian version of the international self-report measure of posttraumatic stress disorder, the Posttraumatic Stress Diagnostic Scale, is reliable and valid in a variety of different adult samples affected by war
Authors: Powell Steve , Rosner Rita
Published: February 2005

Background

The aim of the present study was to assess the internal consistency and discriminant and convergent validity of the Bosnian version of a self-report measure of posttraumatic stress disorder (PTSD), the Posttraumatic Stress Diagnostic Scale (PTDS). The PTDS yields both a PTSD diagnosis according to the Diagnostic and Statistical Manual of Mental Disorders 4th edition (DSM-IV) and a measure of symptom severity.

Methods

812 people living in Sarajevo or in Banja Luka in Bosnia-Herzegovina, of whom the majority had experienced a high number of traumatic war events, were administered the PTDS and other measures of trauma-related psychopathology. The psychometric properties of the instrument were assessed using Cronbach's alpha and principal components analysis, and its construct validity was assessed via Spearman correlation coefficients with the other instruments.

Results

The PTDS and its subscales demonstrated high internal consistency. The principal components revealed by an exploratory analysis are broadly consistent with the DSM-IV subscales except that they reproduce some previously reported difficulties with the "numbing" items from the avoidance subscale. The construct validity of the PTDS was supported by appropriate correlations with other relevant measures of trauma related psychopathology.

Conclusion

The Bosnian version of the PTDS thus appears to be a time-economic and psychometrically sound measure for screening and assessing current PTSD. This self-report measure awaits further validation by interview methods.
One year soy protein supplementation has positive effects on bone formation markers but not bone density in postmenopausal women
Authors: Arjmandi Bahram H , Lucas Edralin A , Khalil Dania A , Devareddy Latha , Smith Brenda J , McDonald Jennifer , Arquitt Andrea B , Payton Mark E , Mason Claudia
Published: February 2005

Background

Although soy protein and its isoflavones have been reported to reduce the risk of osteoporosis in peri- and post-menopausal women, most of these studies are of short duration (i.e. six months). The objective of this study was to examine if one year consumption of soy-containing foods (providing 25 g protein and 60 mg isoflavones) exerts beneficial effects on bone in postmenopausal women.

Methods

Eighty-seven eligible postmenopausal women were randomly assigned to consume soy or control foods daily for one year. Bone mineral density (BMD) and bone mineral content (BMC) of the whole body, lumbar (L1-L4), and total hip were measured using dual energy x-ray absorptiometry at baseline and after one year. Blood and urine markers of bone metabolism were also assessed.

Results and Discussion

Sixty-two subjects completed the one-year long study. Whole body and lumbar BMD and BMC were significantly decreased in both the soy and control groups. However, there were no significant changes in total hip BMD and BMC irrespective of treatment. Both treatments positively affected markers of bone formation as indicated by increased serum bone-specific alkaline phosphatase (BSAP) activity, insulin-like growth factor-I (IGF-I), and osteocalcin (BSAP: 27.8 and 25.8%, IGF-I: 12.8 and 26.3%, osteocalcin: 95.2 and 103.4% for control and soy groups, respectively). Neither of the protein supplements had any effect on urinary deoxypyridinoline excretion, a marker of bone resorption.

Conclusion

Our findings suggest that although one year supplementation of 25 g protein per se positively modulated markers of bone formation, this amount of protein was unable to prevent lumbar and whole body bone loss in postmenopausal women.
Polymorphisms in genes involved in estrogen and progesterone metabolism and mammographic density changes in women randomized to postmenopausal hormone therapy: results from a pilot study
Authors: Lord Sarah J , Mack Wendy J , Van Den Berg David , Pike Malcolm C , Ingles Sue A , Haiman Christopher A , Wang Wei , Parisky Yuri R , Hodis Howard N , Ursin Giske
Published: February 2005

Introduction

Mammographic density is a strong independent risk factor for breast cancer, and can be modified by hormonal exposures. Identifying genetic variants that determine increases in mammographic density in hormone users may be important in understanding hormonal carcinogenesis of the breast.

Methods

We obtained mammograms and DNA from 232 postmenopausal women aged 45 to 75 years who had participated in one of two randomized, double-blind clinical trials with estrogen therapy (104 women, taking 1 mg/day of micronized 17β-estradiol, E2), combined estrogen and progestin therapy (34 women, taking 17β-estradiol and 5 mg/day of medroxyprogesterone acetate for 12 days/month) or matching placebos (94 women). Mammographic percentage density (MPD) was measured on baseline and 12-month mammograms with a validated computer-assisted method. We evaluated polymorphisms in genes involved in estrogen metabolism (catechol-O-methyltransferase (COMT (Val158Met)), cytochrome P450 1B1 (CYP1B1 (Val432Leu)), UDP-glucuronosyltransferase 1A1 (UGT1A1 (<7/≥ 7 TA repeats))) and progesterone metabolism (aldo-keto reductase 1C4 (AKR1C4 (Leu311Val))) with changes in MPD.

Results

The adjusted mean change in MPD was +4.6% in the estrogen therapy arm and +7.2% in the combined estrogen and progestin therapy arm, compared with +0.02% in the placebo arm (P = 0.0001). None of the genetic variants predicted mammographic density changes in women using estrogen therapy. Both the AKR1C4 and the CYP1B1 polymorphisms predicted mammographic density change in the combined estrogen and progestin therapy group (P < 0.05). In particular, the eight women carrying one or two low-activity AKR1C4 Val alleles showed a significantly greater increase in MPD (16.7% and 29.3%) than women homozygous for the Leu allele (4.0%).

Conclusion

Although based on small numbers, these findings suggest that the magnitude of the increase in mammographic density in women using combined estrogen and progestin therapy may be greater in those with genetically determined lower activity of enzymes that metabolize estrogen and progesterone.
The nature of the phagosomal membrane: endoplasmic reticulum versus plasmalemma
Authors: Touret Nicolas , Paroutis Paul , Grinstein Sergio
Published: February 2005

For decades, the vacuole that surrounds particles engulfed by phagocytosis was believed to originate from the plasma membrane. Conversion of the nascent phagosome into a microbicidal organelle was thought to result from the subsequent, orderly fusion of early endosomes, late endosomes, and ultimately, lysosomes with the original plasma membrane-derived vacuole. This conventional model has been challenged, if not superseded, by a revolutionary model that regards phagosome formation as resulting from the particle sliding into the endoplasmic reticulum via an opening at the base of the phagocytic cup. The merits and implications of these two hypotheses are summarized here and analyzed in light of recent results.
Mechanisms Underlying “Functional” Progesterone Withdrawal at Parturition
Authors: BROWN AMY G. , LEITE RITA S. , STRAUSS JEROME F.
Published: February 2005

Abstract: Progesterone is a major factor maintaining uterine quiescence throughout pregnancy. In most species, peripheral progesterone levels decline before initiation of labor, and treatments that inhibit progesterone synthesis or action cause termination of pregnancy and/or premature deliveries. These findings suggest that progesterone withdrawal is required for activation of myometrial contractions. However, in humans, circulating progesterone levels remain elevated until birth, which leads to the notion that a “functional” progesterone withdrawal occurs before parturition. The apparent loss of progesterone sensitivity at term could be a consequence of several different mechanisms including: (1) the catabolism of progesterone in the uterus into inactive compounds; (2) alterations in progesterone receptor (PR) isoform ratios; (3) changes in cofactor protein levels affecting PR transactivation; and (4) inflammation‐induced trans‐repression of PR by nuclear factor κB. All of these mechanisms are potentially capable of decreasing uterine progesterone responsiveness at term, thus enabling the expression of pathways that originally were blocked by progesterone in early pregnancy. However, the specific uterine genes whose transcription is directly controlled by PR, and thus affected by “functional” progesterone withdrawal, remain to be identified.
Number of Transferred Embryos: How to Reduce Multiple Pregnancies
Authors: GERMOND MARC , PRIMI MARIE‐PIERRE , URNER FRANÇOISE , CHANSON ALAIN , WIRTHNER DANIEL , SENN ALFRED
Published: February 2005

Abstract: Because the diagnostic tools for predicting whether an early cleavage stage embryo can lead to a viable pregnancy are still elusive, transfer of more than one embryo remains quite common. However, the only way to reduce multiple pregnancies, considered as the main adverse effect of assisted reproductive technology, is to transfer a single embryo. In countries such as Switzerland and Germany, the law allows cryopreservation only at the 2‐pronuclear stage. This restricts considerably the possibility of selecting the embryos to be transferred. Therefore, a good cryopreservation program at the 2‐pronuclear stage is an essential tool to optimize the efficiency of in vitro fertilization (IVF). We therefore recommend the Cumulated Singleton Delivery Rate (CUSIDERA) as a measure of standard IVF efficiency. This rate averages approximately 23.5% when calculated over the last 10 years in our unit and reaches a value above 35% for patients with more than 10 zygotes. Elective single‐embryo transfers and the decrease of iatrogenic multiple pregnancies in IVF remain dependent on better prognostic tools for the appropriate selection of patients, gametes, and zygotes.
Aging of Oocyte, Ovary, and Human Reproduction
Authors: OTTOLENGHI CHRIS , UDA MANUELA , HAMATANI TOSHIO , CRISPONI LAURA , GARCIA JOSE‐ELIAS , KO MINORU , PILIA GIUSEPPE , SFORZA CHIARELLA , SCHLESSINGER DAVID , FORABOSCO ANTONINO
Published: February 2005

Abstract: We review age‐related changes in the ovary and their effect on female fertility, with particular emphasis on follicle formation, follicle dynamics, and oocyte quality. The evidence indicates that the developmental processes leading to follicle formation set the rules determining follicle quiescence and growth. This regulatory system is maintained until menopause and is directly affected in at least some models of premature ovarian failure (POF), most strikingly in the Foxl2 mouse knockout, a model of human POF with monogenic etiology (blepharophimosis/ptosis/epicanthus inversus syndrome). Several lines of evidence indicate that if the ovarian germ cell lineage maintains regenerative potential, as recently suggested in the mouse, a role in follicle dynamics for germ stem cells, if any, is likely indirect or secondary. In addition, age‐related variations in oocyte quality in animal models suggest that reproductive competence is acquired progressively and might depend on parallel growth and differentiation of follicle cells and stroma. Genomewide analyses of the mouse oocyte transcriptome have begun to be used to systematically investigate the mechanisms of reproductive competence that are altered with aging. Investigative and therapeutic strategies can benefit from considering the role of continuous interactions between follicle cells and oocytes from the beginning of histogenesis to full maturation.
What Criteria for the Definition of Oocyte Quality?
Authors: COTICCHIO GIOVANNI , SERENI ELENA , SERRAO LUCIA , MAZZONE SILVIA , IADAROLA IMMACOLATA , BORINI ANDREA
Published: February 2005

Abstract: Although the spermatozoon provides an essential contribution to the generation of a new individual, the developmental fate of the embryo is principally dictated by the oocyte. Oocyte competencies are acquired throughout oogenesis, via the interaction with somatic cells. The ability to reinitiate the meiotic process and undergo preimplantation development is progressively determined during the antral phase. It is known that these changes involve the nuclear and cytoplasmic compartments, respectively, but the underlying cellular and molecular mechanisms are still poorly understood. Analysis of various aspects of oocyte morphology (cytoplasm, zona pellucida, and polar body) via conventional phase‐contrast microscopy has generated contrasting evidence on the possibility of establishing reliable criteria for the prediction of developmental potential. The introduction of a newly developed microscopy technique based on the detection of polarized light generated by birefringent cell structures has offered the possibility of visualizing noninvasively the meiotic spindle, whose presence is critical for fertilization and later developmental stages. However, further studies are needed to standardize and interpret the information accessible through such a technique. Although unable to preserve cell viability and therefore provide a method by which to select oocytes with superior developmental competence, invasive techniques can make a fundamental contribution to defining objective criteria of oocyte quality. In particular, immunofluorescence analysis, which is able to identify critical anomalies of the meiotic spindle and cytoskeleton organization that can account for oocyte quality, is an important method for assessing the efficiency of in vitro maturation systems.
Endometrial Evaluation in Superovulation Programs: Relationship with Successful Outcome
Authors: TROPEA ANNA , MICELI FIORELLA , MINICI FRANCESCA , ORLANDO MARIATERESA , LAMANNA GIUSEPPINA , GANGALE MARIAFRANCESCA , CATINO STEFANIA , LANZONE ANTONIO , APA ROSANNA
Published: February 2005

Abstract: It is well known that an adequate endometrial receptivity is required for successful implantation in both natural and assisted reproductive cycles. In particular, a brief “implantation window”, during which endometrium undergoes anatomical and molecular changes necessary for embryo implantation, has been observed. The hormonal treatment applied to induce ovulation seems to be able to modify the normal development of the prenidatory endometrium, with possible negative effect on the implantation rate. For this reason, several attempts have been made to identify specific markers of endometrial receptivity, useful for predicting implantation outcome in clinical practice. Even if different histological, immunohistochemical, and ultrasonographic parameters are studied, none unfortunately has been univocally shown to be predictive of pregnancy outcome. Therefore, the evaluation of endometrial receptivity remains a challenge in clinical practice.
Ste20/GCK kinase Nak1/Orb3 polarizes the actin cytoskeleton in fission yeast during the cell cycle
Authors: Leonhard Klaus , Nurse Paul
Published: February 2005

Polar growth is a crucial process during cell morphogenesis. The microtubule and actin cytoskeletons, and vesicular transport are tightly regulated to direct cellular growth and to generate specific cell forms. We demonstrate here that the Ste20-related protein kinase Nak1/Orb3 is required in fission yeast to polarize the actin cytoskeleton at the tips of the cells and for cell separation, and so is involved in controlling both cell shape and late stages of cytokinesis. The localization of the Nak1/Orb3 kinase to the cell tips, a medial ring and the spindle-pole bodies changes during the cell cycle, and the accumulation of F-actin at the cell tips is dependent on Nak1/Orb3 kinase. The phosphorylation of Nak1/Orb3 is periodic during the cell cycle and could be part of a mechanism that relocalizes a constitutively active kinase from the cell tips to the middle of the cell, thereby coordinating reorganization of the actin cytoskeleton and regulation of cell separation with cell-cycle progression.
Another dimension to calcium signaling: a look at extracellular calcium
Authors: Hofer Aldebaran M.
Published: February 2005

Cell biologists know the calcium ion best as a vital intracellular second messenger that governs countless cellular functions. However, the recent identification of cell-surface detectors for extracellular Ca2+ has prompted consideration of whether Ca2+ also functions as a signaling molecule in the extracellular milieu. The cast of Ca2+ sensors includes the well-characterized extracellular-Ca2+-sensing receptor, a G-protein-coupled receptor originally isolated from the parathyroid gland. In addition, other receptors, channels and membrane proteins, such as gap junction hemichannels, metabotropic glutamate receptors, HERG K+ channels and the receptor Notch, are all sensitive to external [Ca2+] fluctuations. A recently cloned Ca2+ sensor (CAS) in Arabidopsis extends this concept to the plant kingdom. Emerging evidence indicates that [Ca2+] in the local microenvironment outside the cell undergoes alterations potentially sufficient to exert biological actions through these sensor proteins. The extracellular space might therefore constitute a much more dynamic Ca2+ signaling compartment than previously appreciated.
The role of non-phenolic lignin in chlorate-forming reactions during chlorine dioxide bleaching of softwood kraft pulp
Authors: Svenson Doug R. , Chang Hou-min , Jameel Hasan , Kadla John F.
Published: February 2005

The affect of phenolic hydroxyl groups on the reaction efficiency during chlorine dioxide pre-bleaching of a softwood kraft pulp was investigated. The removal of phenolic hydroxyl groups via pulp methylation did not adversely affect the chlorine dioxide bleaching efficiency or the amount of chlorate formed during exposure to chlorine dioxide. Ion analysis of the reaction systems revealed that the formation of chloride and chlorite ions during the bleaching process were very similar between the kraft and methylated kraft pulps. These results indicate that the kinetic rates of lignin oxidation by chlorine dioxide and its reduction products, chlorite and hypochlorous acid, are much faster than the rate of inorganic reactions leading to chlorate formation.
Metal chelation studies relevant to wood preservation.1. Complexation of propyl gallate with Fe2+
Authors: Binbuga Nursen , Chambers Kristen , Henry William P. , Schultz Tor P.
Published: February 2005

We previously found that a combination of various organic biocides with low-cost non-biocidal antioxidants gave enhanced (synergistic) efficacy against wood-decaying fungi. The best laboratory results were obtained with propyl gallate, perhaps due to its dual antioxidant/metalchelating properties. In this study we report on potentiometric titration experiments for the complexation of Fe2+ with propyl gallate. The results suggest four coordination compounds are present in the pH range from 3 to 12. These are [(H2PG)Fe]+, (HPG)Fe, [(PG)Fe]−, and [(HPG)2Fe]2− {PG=O3C6H2CO2CH2CH2CH33−}. Equilibrium constants for the formation of all complexes are given. A plot of species present versus pH clearly indicates that propyl gallate strongly complexes with Fe2+ at the mildly acidic pH levels normally present in wood, with some complexing still possible in relatively acidic environments present in decaying wood. Propyl gallate complexes more strongly than catechol at the pH values of normal wood. Propyl gallate may also interfere with the proposed fungal redox cycles. Metal complexation may thus be an important part in the overall mechanism by which propyl gallate and organic biocides synergistically protect wood. Furthermore, the metal chelating properties of heartwood extractives, such as the hydrolysable tannins from which propyl gallate is made, may be an important factor in natural durability.
Solubility of ThO2·xH2O(am) in carbonate solution and the formation of ternary Th(IV) hydroxide-carbonate complexes
Authors: Altmaier M. , Neck Volker , Müller R. , Fanghänel Thomas
Published: February 2005

The solubility of X-ray amorphous Th(IV) hydroxide or hydrous oxide was determined in carbonate solution atI=0.5 M (NaHCO3-Na2CO3-NaOH-NaCl) and 22 °C. Two series of open system experiments were performed under CO2partial pressures of 1.0 and 0.1 bar at -log [H+]=4.5– 7.5. In three series of closed system experiments at constant total carbonate concentrations ofCtot=[HCO3-]+[CO32-]=0.1, 0.04 and 0.015 M, the H+concentration was varied in the range -log [H+] = 8.5–13.5. Some additional solubility data were determined in 0.25–2 M Na2CO3containing 0.1 M NaOH. There was no indication for the formation of a thorium carbonate solid.

The simultaneous evaluation of the different sets of experimental data atI=0.5 M shows that Th(OH)(CO3)45-and Th(OH)2(CO3)22-are the most important ternary complexes. Further contributions to the Th(IV) solubility are coming from Th(OH)2(CO3)(aq), Th(OH)3(CO3)-and Th(OH)4(CO3)2-. Their formation constants, extrapolated toI=0 with the SIT and combined with the solubility product of logK°sp=-47.8±0.3, are calculated to be logβ°114=35.8±0.3, logβ°122=37.0±0.4, logβ°121=30.7±0.4, logβ°131=38.5±0.6 and logβ°141=40.6±0.5. Pure carbonate complexes and other ternary complexes have no significant contributions to the solubility in the present studies atI=0.5 M. Upper limits are derived for their formation constants. Using the SIT for ionic strength corrections, the evaluated set of equilibrium constants is also consistent with the solubility in Na2CO3-NaOH mixtures of higher ionic strength.
It's Not as Simple as It Seems: Ambiguous Culpability and Ambivalent Affect In News Representations of Violent Youth
Authors: Spencer J. William
Published: February 2005

While violence problems are a staple of both the mass media and work by constructionist social problems theorists, most of the latter has focused on violent adults. Constructionist research suggests that the media depict violent persons as evil victimizers, deserving of fear and condemnation, and their victims as deserving of sympathy. This article extends the constructionist literature on violence problems by examining news stories that construct youth violence as a social problem. My findings suggest that these media constructions are considerably more complex than previous work has claimed. Specifically, I find that the media (a) contextualize youth violence by casting extant, familiar social problems as its origins and (b) engender an ambiguous sense of culpability and ambivalent emotional orientations toward violent youth. This complexity is shaped, in part, by the media's appropriation of two seemingly contradictory cultural discourses—the evil, violent predator and the innocent child. I suggest that although aspects of these findings may be specific to the problem of violent youth, the contextualization, ambiguity, and ambivalence may well be found in social constructions of a variety of other problems.
Effect of Teosinte Cytoplasmic Genomes on Maize Phenotype
Authors: Allen James O
Published: February 2005

Determining the contribution of organelle genes to plant phenotype is hampered by several factors, including the paucity of variation in the plastid and mitochondrial genomes. To circumvent this problem, evolutionary divergence between maize (Zea mays ssp. mays) and the teosintes, its closest relatives, was utilized as a source of cytoplasmic genetic variation. Maize lines in which the maize organelle genomes were replaced through serial backcrossing by those representing the entire genus, yielding alloplasmic sublines, or cytolines were created. To avoid the confounding effects of segregating nuclear alleles, an inbred maize line was utilized. Cytolines with Z. mays teosinte cytoplasms were generally indistinguishable from maize. However, cytolines with cytoplasm from the more distantly related Z. luxurians, Z. diploperennis, or Z. perennis exhibited a plethora of differences in growth, development, morphology, and function. Significant differences were observed for 56 of the 58 characters studied. Each cytoline was significantly different from the inbred line for most characters. For a given character, variation was often greater among cytolines having cytoplasms from the same species than among those from different species. The characters differed largely independently of each other. These results suggest that the cytoplasm contributes significantly to a large proportion of plant traits and that many of the organelle genes are phenotypically important.