bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationship Between Lipid Abnormalities and Insulin Resistance in Japanese School Children
Authors: Asato Yoshihide , Katsuren Keisuke , Ohshiro Tadashi , Kikawa Kazuhide , Shimabukuro Tadao , Ohta Takao
Published: September 2006

Objective—

Dyslipidemia and insulin resistance (IR) are risk factors for coronary heart disease (CHD) in adults. To help prevent the development of CHD, it may be useful to understand the relationship between lipid abnormalities and IR during childhood.

Methods and Results—

IR was assessed by the homeostasis model approximation index. We studied 1175 Japanese school children (642 boys and 533 girls), aged between 7 and 12 years. Obesity was defined by the body mass index standard deviation score (BMISD) (obese: BMISD ≥2.0). BMISD was most significantly associated with IR in nonobese children (
P
=0.000). Associations of IR with lipid-related parameters were affected by BMISD. After being corrected by BMISD, in nonobese children, log triglycerides (TG), apoB and low-density lipoprotein (LDL) size in boys and log TG, LDL size, and high-density lipoprotein (HDL) cholesterol in girls were still significantly associated with IR (
P
=0.000 to 0.017). In obese children, all parameters except for LDL cholesterol in boys and LDL size in girls were significantly associated with IR (
P
=0.000 to 0.030). Multiple regression analysis showed that log TG and LDL size in nonobese children, log TG in obese boys and LDL size in obese girls were independently associated with IR. Children with IIb and IV hyperlipidemia had significantly higher IR than those with normolipidemia and IIa, even after correcting for BMISD and age.

Conclusion—

Our results suggest that in addition to controlling body weight, it may be important for school children to characterize lipid phenotypes to prevent progression to CHD and/or type 2 diabetes and to identify subjects who are at high risk for these disorders.
Cardiac Overexpression of Monocyte Chemoattractant Protein-1 in Transgenic Mice Prevents Cardiac Dysfunction and Remodeling After Myocardial Infarction
Authors: Morimoto Hajime , Takahashi Masafumi , Izawa Atsushi , Ise Hirohiko , Hongo Minoru , Kolattukudy Pappachan E. , Ikeda Uichi
Published: September 2006

Myocardial infarction (MI) is accompanied by inflammatory responses that lead to the recruitment of leukocytes and subsequent myocardial damage, healing, and scar formation. Because monocyte chemoattractant protein-1 (MCP-1) (also known as CCL2) regulates monocytic inflammatory responses, we investigated the effect of cardiac MCP-1 overexpression on left ventricular (LV) dysfunction and remodeling in a murine MI model. Transgenic mice expressing the mouse JE-MCP-1 gene under the control of the α-cardiac myosin heavy chain promoter (MHC/MCP-1 mice) were used for this purpose. MHC/MCP-1 mice had reduced infarct area and scar formation and improved LV dysfunction after MI. These mice also showed induction of macrophage infiltration and neovascularization; however, few bone marrow-derived endothelial cells were detected in MHC/MCP-1 mice whose bone marrow was replaced with that of Tie2/LacZ transgenic mice. Flow cytometry analysis showed no increase in endothelial progenitor cells (CD34
+
/Flk-1
+
cells) in MHC/MCP-1 mice. Marked myocardial interleukin (IL)-6 secretion, STAT3 activation, and LV hypertrophy were observed after MI in MHC/MCP-1 mice. Furthermore, cardiac myofibroblasts accumulated after MI in MHC/MCP-1 mice. In vitro experiments revealed that a combination of IL-6 with MCP-1 synergistically stimulated and sustained STAT3 activation in cardiomyocytes. MCP-1, IL-6, and hypoxia directly promoted the differentiation of cardiac fibroblasts into myofibroblasts. Our results suggest that cardiac overexpression of MCP-1 induced macrophage infiltration, neovascularization, myocardial IL-6 secretion, and accumulation of cardiac myofibroblasts, thereby resulting in the prevention of LV dysfunction and remodeling after MI. They also provide a new insight into the role of cardiac MCP-1 in the pathophysiology of MI.
Parental Longevity, Carotid Atherosclerosis, and Aortic Arterial Stiffness in Adult Offspring
Authors: Zureik Mahmoud , Czernichow Sébastien , Courbon Dominique , Blacher Jacques , Ducimetière Pierre , Hercberg Serge , Safar Michel E. , Galan Pilar
Published: September 2006

Background and Purpose—

We examined the associations of parental longevity with carotid intima-media thickness, carotid plaques, and aortic arterial stiffness in adult offspring.

Methods—

A population of 1117 volunteers who participated in the SUVIMAX Vascular Study (mean age, 59.7 years; 49.0% women) were included. Carotid-femoral pulse-wave velocity (PWV) was used to assess aortic stiffness. Carotid B-mode ultrasound examination included measurements (at sites free of plaque) of intima-media thickness at the common carotid arteries and assessment of atherosclerotic plaques in the extracranial carotid arteries.

Results—

The prevalence of carotid plaques in subjects whose fathers had died at <65 years, in those whose fathers were alive at 65 years but who had died by 80 years, and in those whose fathers were alive at 80 years was 40.4%, 30.4%, and 28.9%, respectively (
P
<0.001). The multivariate odds ratios of carotid plaques in the 3 groups of paternal longevity, adjusted for conventional cardiovascular risk factors, were 1, 0.68 (95% CI, 0.48 to 0.96), and 0.69 (95% CI, 0.49 to 0.98), respectively. The mean common carotid arteries intima-media thickness was higher in subjects with premature paternal death in univariate (
P
<0.007) but not in multivariate (
P
=0.39) analyses. Mean PWV decreased with increasing paternal longevity in both univariate and multivariate analyses. The multivariate-adjusted means of PWV in the 3 groups of paternal longevity were 11.9±0.14, 11.7±0.12, and 11.0±0.12 m/s (
P
<0.0001), respectively. In contrast, neither B-mode ultrasound measurements nor PWV measurements were associated with maternal longevity.

Conclusion—

These results may indicate that there are modifications of structure and function of large arteries according to paternal longevity.
Activation of Preexisting and Acquired Face Representations: The N250 Event-related Potential as an Index of Face Familiarity
Authors: Tanaka James W. , Curran Tim , Porterfield Albert L. , Collins Daniel
Published: September 2006

Electrophysiological studies using event-related potentials have demonstrated that face stimuli elicit a greater negative brain potential in right posterior recording sites 170 msec after stimulus onset (N170) relative to nonface stimuli. Results from repetition priming paradigms have shown that repeated exposures of familiar faces elicit a larger negative brainwave (N250r) at inferior temporal sites compared to repetitions of unfamiliar faces. However, less is known about the time course and learning conditions under which the N250 face representation is acquired. In the familiarization phase of the Joe/no Joe task, subjects studied a target “Joe” face (“Jane” for female subjects) and, during the course of the experiment, identified a series of sequentially presented faces as either Joe or not Joe. The critical stimulus conditions included the subject's own face, a same-sex Joe ( Jane) face and a same-sex “other” face. The main finding was that the subject's own face produced a focal negative deflection (N250) in posterior channels relative to nontarget faces. The task-relevant Joe target face was not differentiated from other nontarget faces in the first half of the experiment. However, in the second half, the Joe face produced an N250 response that was similar in magnitude to the own face. These findings suggest that the N250 indexes two types of face memories: a preexperimentally familiar face representation (i.e., the “own face” and a newly acquired face representation (i.e., the Joe/Jane face) that was formed during the course of the experiment.
Contribution of Familiarity and Recollection to Associative Recognition Memory: Insights from Event-related Potentials
Authors: Opitz Bertram , Cornell Sonia
Published: September 2006

Within the dual-process perspective of recognition memory, it has been claimed that familiarity is sufficient to support recognition of single items, but recollection is necessary for associative recognition of item pairs. However, there are some reports suggesting that familiarity might support associative recognition judgments when the items form an easy to access bound representation. In contrast, recollection seems to be required for the recognition of bindings that might be flexibly rearranged in novel situations. We investigated whether both forms of binding are mediated by different mechanisms as reflected by a qualitatively different spatiotemporal eventrelated potential (ERP) pattern. In a recognition memory experiment, subjects gave old/new judgments to words learned by focusing either on interitem associations or on size relation of word triplets. Results revealed higher hit rates in the relational condition as compared to the associative condition. In addition, the proportion of triplets from which all three items were remembered was significantly larger in the relational condition suggesting that memory retrieval in this condition relies primarily on bound representations of word triplets. The ERP revealed a late parietal old/new effect for both conditions, with relational processing resulting in a greater effect. In contrast, an early frontal old/new effect was solely present in the associative condition. Taken together, these data provide evidence that familiarity might support associative recognition if the associated components are coherently encoded into a bound representation. Recollection might foster the recognition of relational bindings among items. This indicates that the contribution of familiarity and recollection to associative recognition depends on the kind of binding operations performed on the items rather than on the single versus multiple item distinction.
Blessed Men and Tribal Politics: Notes on Political Culture in the Indo-Afghan World
Authors: Green Nile
Published: September 2006

This article examines some of the foundations of the political culture of the Afghan communities of medieval North India through analysing the roles of Sufis and Sayyids in the arbitration of disputes. The social roles of such 'blessed men' are interpreted as part of a wider political culture in which places, objects and persons of mediation functioned on both the small scale of private quarrels and the grander scale of tribal and 'state' diplomacy. In both cases, the origins of this political culture are seen as a reflection of the segmentary society of the Indo-Afghan frontier and a response to the recurring interaction of its mobile social groups in India and beyond. Cet article s'attache à élucider les fondements de la culture politique des communautés afghanes de l'Inde médiévale en examinant les rôles qu'ont joués les soufies et les sayyids dans l'arbitrage des disputes. Ces 'hommes bénis' font partie intégrante d'une culture politique au sein de laquelle circulent objets, lieux et personnes médiatrices ; leur in fluence s'exerce tant au niveau des querelles personnelles qu'au niveau de la diplomatie de la tribu et de 'l'état'. Dans les deux cas, les origines de cette culture politique sont perçues comme re flet de la société segmentée de la frontière indo-afghane et comme réponse à l'interaction répétée de ces groupes sociaux en Inde et ailleurs.
Orographic Enhancement of Precipitation over Low Mountain Ranges. Part I: Model Formulation and Idealized Simulations
Authors: Kunz Michael , Kottmeier Christoph
Published: September 2006

A diagnostic model for simulating orographic precipitation over low mountain ranges is presented. It is based on linear theory of hydrostatic flow over mountains and calculates condensation rates from vertical lifting at the different model layers. Several other physical processes, such as hydrometeor drifting, evaporation, and moisture loss, are incorporated in the model by simple parameterizations. Idealized simulations of precipitation with different model performances provide insight into the physical processes of orographic precipitation. Evaporation, in combination with hydrometeor drifting into descent regions, is identified as one of the key aspects that primarily determine the spatial distribution of precipitation. The variability in orographic precipitation that results from changes in model parameters and ambient conditions is investigated in sensitivity studies. Simulated intensities as well as their spatial distributions are very sensitive to the temperature T0 at the lowest layer and to the variables that define the Froude number Frm: the horizontal wind speed U, static stability Nm, and mountain height H. Most of the parameters exhibit a nonlinear relation to the simulated precipitation intensities. Relative to ambient conditions, orographic precipitation is found to be less sensitive to changes in formation time tice, terminal velocity of ice particles υice, and melting level Δz. In each case, the sensitivities of simulation results strongly depend on the location in the model domain.
Extending the Predictability of Hydrometeorological Flood Events Using Radar Rainfall Nowcasting
Authors: Vivoni Enrique R. , Entekhabi Dara , Bras Rafael L. , Ivanov Valeriy Y. , Van Horne Matthew P. , Grassotti Christopher , Hoffman Ross N.
Published: September 2006

The predictability of hydrometeorological flood events is investigated through the combined use of radar nowcasting and distributed hydrologic modeling. Nowcasting of radar-derived rainfall fields can extend the lead time for issuing flood and flash flood forecasts based on a physically based hydrologic model that explicitly accounts for spatial variations in topography, surface characteristics, and meteorological forcing. Through comparisons to discharge observations at multiple gauges (at the basin outlet and interior points), flood predictability is assessed as a function of forecast lead time, catchment scale, and rainfall spatial variability in a simulated real-time operation. The forecast experiments are carried out at temporal and spatial scales relevant for operational hydrologic forecasting. Two modes for temporal coupling of the radar nowcasting and distributed hydrologic models (interpolation and extended-lead forecasting) are proposed and evaluated for flood events within a set of nested basins in Oklahoma. Comparisons of the radar-based forecasts to persistence show the advantages of utilizing radar nowcasting for predicting near-future rainfall during flood event evolution.
Stochastic Modeling of Daily Summertime Rainfall over the Southwestern United States. Part I: Interannual Variability
Authors: Wang Jingyun , Anderson Bruce T. , Salvucci Guido D.
Published: September 2006

The interannual variability of summertime daily precipitation at 78 stations in the southwestern United States is studied using chain-dependent models and nonparametric empirical distributions of daily rainfall amounts. Modeling results suggest that a second-order chain-dependent model can optimally portray the temporal structure of the summertime daily precipitation process over the southwestern United States. The unconditioned second-order chain-dependent model, in turn, can explain approximately 75% of the interannual variance in the seasonal total wet days over the region and 83% of the interannual variance in the seasonal total precipitation. In addition, only a small fraction (generally smaller than 20%) of the observed years at any given station show statistically significant changes in the occurrence and intensity characteristics, related to either the number of seasonal total wet days or the distributions of daily rainfall amounts. Investigations of the year-to-year variations in the occurrence and intensity characteristics indicate that both variations are random (on interannual time scales), and they display similar significance in explaining the remaining 17% of interannual variance of seasonal total precipitation over the region. However, numerical tests suggest that the interannual variations of the two are not independent for the summertime monsoon precipitation, and that complex covariability that cannot be described with simple stochastic statistical models may exist between them.
Multimodel Combination Techniques for Analysis of Hydrological Simulations: Application to Distributed Model Intercomparison Project Results
Authors: Ajami Newsha K. , Duan Qingyun , Gao Xiaogang , Sorooshian Soroosh
Published: September 2006

This paper examines several multimodel combination techniques that are used for streamflow forecasting: the simple model average (SMA), the multimodel superensemble (MMSE), modified multimodel superensemble (M3SE), and the weighted average method (WAM). These model combination techniques were evaluated using the results from the Distributed Model Intercomparison Project (DMIP), an international project sponsored by the National Weather Service (NWS) Office of Hydrologic Development (OHD). All of the multimodel combination results were obtained using uncalibrated DMIP model simulations and were compared against the best-uncalibrated as well as the best-calibrated individual model results. The purpose of this study is to understand how different combination techniques affect the accuracy levels of the multimodel simulations. This study revealed that the multimodel simulations obtained from uncalibrated single-model simulations are generally better than any single-member model simulations, even the best-calibrated single-model simulations. Furthermore, more sophisticated multimodel combination techniques that incorporated bias correction step work better than simple multimodel average simulations or multimodel simulations without bias correction.
Noise Reduction of Atmospheric Emitted Radiance Interferometer (AERI) Observations Using Principal Component Analysis
Authors: Turner D. D. , Knuteson R. O. , Revercomb H. E. , Lo C. , Dedecker R. G.
Published: September 2006

A principal component noise filter has been applied to ground-based high-spectral-resolution infrared radiance observations collected by the Atmospheric Emitted Radiance Interferometers (AERIs) deployed by the Atmospheric Radiation Measurement (ARM) program. The technique decomposes the radiance observations into their principal components, selects the ones that describe the most variance in the data, and reconstructs the data from these components. An empirical function developed for chemical analysis is utilized to determine the number of principal components to be used in the reconstruction of the data. Statistical analysis of the noise-filtered minus original radiance data, as well as side-by-side analysis of data from two AERI systems utilizing different temporal sampling, demonstrates the ability of the noise filter using this empirical function to retain most of the atmospheric signal above the AERI noise level in the filtered data. The noise filter is applied to data collected at ARM’s tropical, midlatitude, and Arctic sites, demonstrating that the random variability in the data is reduced by 5% to over 450%, depending on the spectral element and location of the instrument. A seasonal analysis of the number of principal components required by the noise filter for each site shows a strong seasonal dependence in the atmospheric variability at the Arctic and midlatitude sites but not at the tropical site.
Entrainment and Transport in Idealized Three-Dimensional Gravity Current Simulation
Authors: Tseng Yu-Heng , Dietrich David E.
Published: September 2006

A purely z-coordinate Dietrich/Center for Air Sea Technology (DieCAST) ocean model is applied to the Dynamics of Overflow Mixing and Entrainment (DOME) idealized bottom density current problem that is patterned after the Denmark Strait. The numerical results show that the background viscosity plays a more important role than the chosen coordinate system in the entrainment and mixing if the background viscosity is not small enough. Both higher horizontal viscosity and coarser resolution leads to slower along-slope propagation. Reducing vertical mixing parameterization also leads to slower along-slope propagation with thicker plume size vertically. The simulation gives consistent results for the moderate- and fine-resolution runs. At a very coarse grid the dense water descends more slowly and is mainly dominated by diffusion. Time-averaged downstream transport and entrainment are not very sensitive to viscosity after the flow reaches its quasi-steady status. However, more realistic eddies and flow structures are found in low-viscosity runs. The results show good convergence of the resolved flow as expected and clarify the effects of numerical dissipation/mixing on overflow modeling. Larger numerical dissipation is not required nor recommended in z-coordinate models.
Comparison of Impacts of WRF Dynamic Core, Physics Package, and Initial Conditions on Warm Season Rainfall Forecasts
Authors: Gallus William A. , Bresch James F.
Published: September 2006

A series of simulations for 15 events occurring during August 2002 were performed using the Weather Research and Forecasting (WRF) model over a domain encompassing most of the central United States to compare the sensitivity of warm season rainfall forecasts with changes in model physics, dynamics, and initial conditions. Most simulations were run with 8-km grid spacing. The Advanced Research WRF (ARW) and the nonhydrostatic mesoscale model (NMM) dynamic cores were used. One physics package (denoted NCEP) used the Betts–Miller–Janjic convective scheme with the Mellor–Yamada–Janjic planetary boundary layer (PBL) scheme and GFDL radiation package; the other package (denoted NCAR) used the Kain–Fritsch convective scheme with the Yonsei University PBL scheme and the Dudhia rapid radiative transfer model radiation. Other physical schemes were the same (e.g., the Noah land surface model, Ferrier et al. microphysics) in all runs. Simulations suggest that the sensitivity of the model to changes in physics is a function of which the dynamic core is used, and the sensitivity to the dynamic core is a function of the physics used. The greatest sensitivity in general is associated with a change in physics packages when the NMM core is used. Sensitivity to a change in physics when the ARW core is used is noticeably less. For light rainfall, the spread in the rainfall forecasts when physics are changed under the ARW core is actually less at most times than when the dynamic core is changed while NCAR physics are used. For light rainfall, the WRF model using NCAR physics is much more sensitive to a change in dynamic core than the WRF model using NCEP physics. For heavier rainfall, the opposite is true with a greater sensitivity occurring when NCEP physics is used. Sensitivity to initial conditions (Eta versus the Rapid Update Cycle with an accompanying small change in grid spacing) is generally less substantial than the sensitivity to changes in dynamic core or physics, except in the first 6–12 h of the forecast when it is comparable. As might be expected for warm season rainfall, the finescale structure of rainfall forecasts is more affected by the physics used than the dynamic core used. Surprisingly, however, the overall areal coverage and rain volume within the domain may be more influenced by the dynamic core choice than the physics used.
Photoperiod Differentially Affects Immune Function and Reproduction in Collared Lemmings (Dicrostonyx groenlandicus)
Authors: Weil Zachary M. , Martin Lynn B. , Nelson Randy J.
Published: September 2006

Many nontropical rodent species experience predictable annual variation in resource availability and environmental conditions. Individuals of many animal species engage in energetically expensive processes such as breeding during the spring and summer but bias investment toward processes that promote survival such as immune function during the winter. Generally, the suite of responses associated with the changing seasons can be induced by manipulating day length (photoperiod). Collared lemmings ( Dicrostonyx groenlandicus) are arvicoline rodents that inhabit parts of northern Canada and Greenland. Despite the extreme conditions of winter in their native habitat, these lemmings routinely breed during the winter. In the laboratory, collared lemmings have divergent responses to photoperiod relative to other seasonally breeding rodents; short day lengths can stimulate, rather than inhibit, the reproductive system. Male and female collared lemmings were maintained for 11 weeks in 1 of 3 photoperiods (LD 22:2, LD 16:8, or LD 8:16) that induce markedly different phenotypes. Following photoperiod treatment, cell-mediated immune function as assessed by delayed-type hypersensitivity reactions was elevated in lemmings housed in LD 16:8 and LD 8:16 relative to LD 22:2. However, antibody production to a novel antigen was unaffected by photoperiod. Exposure to LD 8:16 induced weight gain, molt to a winter pelage, and in contrast to previous studies, regression of the male, but not the female, reproductive tract. In conclusion, these data indicate that components of immune function among collared lemmings are responsive to changes in day length.
Transcriptional Profiling in the Adrenal Gland Reveals Circadian Regulation of Hormone Biosynthesis Genes and Nucleosome Assembly Genes
Authors: Oster Henrik , Damerow Sebastian , Hut Roelof A. , Eichele Gregor
Published: September 2006

The master circadian pacemaker of the suprachiasmatic nuclei coordinates behavioral and physiological rhythms via synchronization of subordinate peripheral oscillators in the central nervous system and organs throughout the body. Among these organs, the adrenal glands hold a prime position because of their regulatory influence on numerous physiological functions via rhythmic secretion of catecholamines and corticoid hormones into the bloodstream. In this report, the authors perform whole genome microarray hybridization to characterize the circadian transcriptome of the murine adrenal. They show that ~5% of the mouse genome is under circadian control in this gland. Using gene ontology analysis, they identify classes of transcripts that may synchronize adrenal hormone production. The authors' expression profiling also revealed that multiple histone genes implicated in either DNA replication or transcriptional regulation are clock controlled, suggesting a novel way by which the circadian clock may regulate the chromatin state.
Smad1 expands the hemangioblast population within a limited developmental window
Authors: Zafonte Brian T. , Liu Susanna , Lynch-Kattman Macarena , Torregroza Ingrid , Benvenuto Luke , Kennedy Marion , Keller Gordon , Evans Todd
Published: September 2006

Bone morphogenetic protein (BMP) signaling is an important regulator of hematovascular development. However, the progenitor population that responds to BMP signaling is undefined, and the relative role of downstream mediators including Smad1 is unclear. We find that Smad1 shows a distinctive expression profile as embryonic stem (ES) cells undergo differentiation in the embryoid body (EB) system, with peak levels in cell populations enriched for the hemangioblast. To test the functional relevance of this observation, we generated an ES cell line that allows temporal control of ectopic Smad1 expression. Continuous expression of Smad1 from day 2 of EB culture does not disturb hematopoiesis, according to colony assays. In contrast, a pulse of Smad1 expression exclusively between day 2 and day 2.25 expands the population of progenitors for primitive erythroblasts and other hematopoietic lineages. This effect correlates with increased levels of transcripts encoding markers for the hemangioblast, including Runx1, Scl, and Gata2. Indeed, the pulse of Smad1 induction also expands the blast colony-forming cell (BL-CFC) population at a level that is fully sufficient to explain subsequent increases in hematopoiesis. Our data demonstrate that Smad1 expression is sufficient to expand the number of cells that commit to hemangioblast fate.
Low rhodamine 123 retention identifies long-term human hematopoietic stem cells within the Lin−CD34+CD38− population
Authors: McKenzie Joby L. , Takenaka Katsuto , Gan Olga I. , Doedens Monica , Dick John E.
Published: September 2006

Progress to uncover the molecular and cellular regulators that govern human hematopoietic stem cell (HSC) fate has been impeded by an inability to obtain highly purified fractions of HSCs. We report that the rhodamine 123 (Rho 123) dye effluxing fraction of the Lin−CD34+CD38− population contains SCID-repopulating cells (SRCs) capable of long-term repopulation in primary nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. Purification based on Rho uptake led to a 4-fold enrichment of SRCs in the Lin−CD34+CD38− fraction, with a frequency of 1 SRC in 30 Lin−CD34+CD38−Rholo cells. The Lin−CD34+CD38−Rholo fraction also possesses long-term self-renewal capacity as measured by serial transplantation totaling more than 20 weeks. We conclude that Rho dye efflux provides an additional means of purifying human HSCs in the quest to achieve homogeneous populations of primitive cells for both experimental and therapeutic applications.
Origin of mitochondrial DNA diversity of domestic yaks
Authors: Guo Songchang , Savolainen Peter , Su Jianping , Zhang Qian , Qi Delin , Zhou Jie , Zhong Yang , Zhao Xinquan , Liu Jianquan
Published: September 2006

Background

The domestication of plants and animals was extremely important anthropologically. Previous studies have revealed a general tendency for populations of livestock species to include deeply divergent maternal lineages, indicating that they were domesticated in multiple, independent events from genetically discrete wild populations. However, in water buffalo, there are suggestions that a similar deep maternal bifurcation may have originated from a single population. These hypotheses have rarely been rigorously tested because of a lack of sufficient wild samples. To investigate the origin of the domestic yak (Poephagus grunnies), we analyzed 637 bp of maternal inherited mtDNA from 13 wild yaks (including eight wild yaks from a small population in west Qinghai) and 250 domesticated yaks from major herding regions.

Results

The domestic yak populations had two deeply divergent phylogenetic groups with a divergence time of > 100,000 yrs BP. We here show that haplotypes clustering with two deeply divergent maternal lineages in domesticated yaks occur in a single, small, wild population. This finding suggests that all domestic yaks are derived from a single wild gene pool. However, there is no clear correlation of the mtDNA phylogenetic clades and the 10 morphological types of sampled yaks indicating that the latter diversified recently. Relatively high diversity was found in Qinghai and Tibet around the current wild distribution, in accordance with previous suggestions that the earliest domestications occurred in this region. Conventional molecular clock estimation led to an unrealistic early dating of the start of the domestication. However, Bayesian estimation of the coalescence time allowing a relaxation of the mutation rate are better in agreement with a domestication during the Holocene as supported by archeological records.

Conclusion

The information gathered here and the previous studies of other animals show that the demographic histories of domestication of livestock species were highly diverse despite the common general feature of deeply divergent maternal lineages. The results further suggest that domestication of local wild prey ungulate animals was a common occurrence during the development of human civilization following the postglacial colonization in different locations of the world, including the high, arid Qinghai-Tibetan Plateau.
Human fetal neuroblast and neuroblastoma transcriptome analysis confirms neuroblast origin and highlights neuroblastoma candidate genes
Authors: De Preter Katleen , Vandesompele Jo , Heimann Pierre , Yigit Nurten , Beckman Siv , Schramm Alexander , Eggert Angelika , Stallings Raymond L , Benoit Yves , Renard Marleen , Paepe Anne De , Laureys Geneviève , Påhlman Sven , Speleman Frank
Published: September 2006

Background

Neuroblastoma tumor cells are assumed to originate from primitive neuroblasts giving rise to the sympathetic nervous system. Because these precursor cells are not detectable in postnatal life, their transcription profile has remained inaccessible for comparative data mining strategies in neuroblastoma. This study provides the first genome-wide mRNA expression profile of these human fetal sympathetic neuroblasts. To this purpose, small islets of normal neuroblasts were isolated by laser microdissection from human fetal adrenal glands.

Results

Expression of catecholamine metabolism genes, and neuronal and neuroendocrine markers in the neuroblasts indicated that the proper cells were microdissected. The similarities in expression profile between normal neuroblasts and malignant neuroblastomas provided strong evidence for the neuroblast origin hypothesis of neuroblastoma. Next, supervised feature selection was used to identify the genes that are differentially expressed in normal neuroblasts versus neuroblastoma tumors. This approach efficiently sifted out genes previously reported in neuroblastoma expression profiling studies; most importantly, it also highlighted a series of genes and pathways previously not mentioned in neuroblastoma biology but that were assumed to be involved in neuroblastoma pathogenesis.

Conclusion

This unique dataset adds power to ongoing and future gene expression studies in neuroblastoma and will facilitate the identification of molecular targets for novel therapies. In addition, this neuroblast transcriptome resource could prove useful for the further study of human sympathoadrenal biogenesis.
The untraceable events method for absorbing processes
Authors: Nakatsuka Toshinao
Published: September 2006

In this paper we propose a new method of determining the stability of queueing systems. We attain it using the absorbing process and introduce the untraceable events method to show the existence of the absorbing process. The advantage of our method is that we are able to discuss the stability of various variables for both discrete and continuous parameters in a general framework with nonstationary input. An untraceable event has the property that the state loses the memory of its origin. In a concrete model, we use the boundedness of the state at an epoch in time with respect to the initial condition and choose the form of the untraceable event corresponding to the input distribution.
A martingale characterization of Pólya-Lundberg processes
Authors: Niese Birgit
Published: September 2006

We study exponential families within the class of counting processes and show that a mixed Poisson process belongs to an exponential family if and only if it is either a Poisson process or has a gamma structure distribution. This property can be expressed via exponential martingales.
Dependence ordering for Markov processes on partially ordered spaces
Authors: Daduna Hans , Szekli Ryszard
Published: September 2006

We compare dependence in stochastically monotone Markov processes with partially ordered Polish state spaces using the concordance and supermodular orders. We show necessary and sufficient conditions for the concordance order to hold both in terms of the one-step transition probabilities for discrete-time processes and in terms of the corresponding infinitesimal generators for continuous-time processes. We give examples showing that a stochastic monotonicity assumption is not necessary for such orderings. We indicate relations between dependence orderings and, variously, the asymptotic variance-reduction effect in Monte Carlo Markov chains, Cheeger constants, and positive dependence for Markov processes.
A discrete multivariate distribution resulting from the law of small numbers
Authors: Hoshino Nobuaki
Published: September 2006

In the present article we derive a new discrete multivariate distribution using a limiting argument that is essentially the same as the law of small numbers. The distribution derived belongs to an exponential family, and randomly partitions positive integers. The facts shown about the distribution are useful in many fields of application involved with count data. The derivation parallels that of the Ewens distribution from the gamma distribution, and the new distribution is produced from the inverse Gaussian distribution. The method employed is regarded as the discretization of an infinitely divisible distribution over nonnegative real numbers.
Screening for abdominal aortic aneurysm by general practitioners and practice-based ultrasonographers
Authors: Laws Catharine , Eastman Jo
Published: September 2006

Aim: To find out if aortic aneurysm screening could be successfully organized from a general practice with ultrasound facilities, and to offer a screening service to surrounding general practices within a primary health care trust (PHCT) in Surrey.

Methods: The study screened men between the ages of 65 and 80 years for abdominal aortic aneurysm (AAA). The screening project was set up and carried out entirely in primary care (in local practices). Funding was received from the PHCT; the costs of the screening programme had to fit within this budget.

Results: There was a 71.7% attendance rate and 4.1% of the screened population had an AAA. The screens cost approximately £17.39 per scan.

Conclusions: The costs for the screening programme were low, although it is hard to find direct comparisons. The attendance rate could be improved, but the prevalence of AAA in this study was comparable to those found in hospital-led screening trials.
Atrophy of the stria vascularis, a common cause for hearing loss.
Authors: Schuknecht Harold F. , Watanuki Kozo , Takahashi Tadahiko , Aziz Belal A. , Kimura Robert S. , Jones Diane Deleo , Ota Carol Y.
Published: September 2006

Atrophy of the stria vascularis is a genetically determined deafness of aging characterized by a bilateral symmetrical sensori‐neural hearing loss showing flat audiometric patterns and excellent speech discrimination. The temporal bones of individuals exhibiting this type of hearing loss were studied by serial sections and surface preparations for light microscopy and by electron microscopy. The atrophic changes are most severe in the apical regions of the cochleas and involve the marginal, intermediate and basal cells in that order of severity. It seems probable that atrophy of the stria vascularis causes some deficiency in the quality of endolymph throughout the cochlear duct, regardless of the location of the atrophy. Typically all other structures of the cochlear duct are normal, and the sense organ when stimulated within its sensitivity range is capable of normal stimulus coding, thus accounting for the usually excellent speech discrimination.
Surveillance for Early Detection of Aggressive Parathyroid Disease: Carcinoma and Atypical Adenoma in Familial Isolated Hyperparathyroidism Associated With a Germline HRPT2 Mutation
Authors: Kelly Thomas G , Shattuck Trisha M , Reyes-Mugica Miguel , Stewart Andrew F , Simonds William F , Udelsman Robert , Arnold Andrew , Carpenter Thomas O
Published: September 2006

Familial hyperparathyroid syndromes involving mutations of HRPT2 (also CDC73), a tumor suppressor, are important to identify because the relatively high incidence of parathyroid malignancy associated with such mutations warrants a specific surveillance strategy. However, there is a dearth of reports describing experience with surveillance and early detection informed by genetic insight into this disorder.

Introduction: Familial isolated hyperparathyroidism (FIHP) is a rare cause of parathyroid (PT) tumors without other neoplasms or endocrinopathies. Germline mutations in CASR, MEN1, and rarely, HRPT2 have been identified in kindreds with FIHP. HRPT2 mutations may be enriched in FIHP families with PT carcinoma, underscoring the importance of identifying causative mutations.

Materials and Methods: A 13-year-old boy, whose father had died of PT carcinoma, developed primary hyperparathyroidism. A left superior PT mass was identified by ultrasonography and removed surgically. Aggressive histological features of the boy's tumor included fibrous trabeculae, mitoses, and microscopic capsular infiltration. Two years later, under close biochemical surveillance, primary hyperparathyroidism recurred 5 months after documentation of normocalcemia and normal parathyroid status. Ultrasound and MRI identified a newly enlarged right superior PT gland but indicated no recurrent disease in the left neck. Histologic features typical of a benign adenoma were evident after surgical extirpation of the gland.

Results: Leukocyte DNA analysis revealed a frameshift mutation in exon 2 of HRPT2. The initial tumor manifested the expected germline HRPT2 mutation, plus a distinct somatic frameshift mutation, consistent with the Knudson “two hit” concept of biallelic inactivation of a classic tumor suppressor gene. Genetic screening of the patient's 7 asymptomatic and previously normocalcemic siblings revealed three with the same germline HRPT2 mutation. One of the siblings newly identified as mutation-positive was noted to be hypercalcemic at the time of the genetic screening. He was found to have a PT adenoma with aggressive features. Two of the five children of another mutation-positive sibling also carry the same HRPT2 mutation.

Conclusions: Despite the reported rarity of HRPT2 mutations in FIHP, a personal or family history of PT carcinoma in FIHP mandates serious consideration of germline HRPT2 mutation status. This information can be used in diagnostic and management considerations, leading to early detection and removal of potentially malignant parathyroid tumors.
Adiponectin Stimulates RANKL and Inhibits OPG Expression in Human Osteoblasts Through the MAPK Signaling Pathway
Authors: Luo Xiang-Hang , Guo Li-Juan , Xie Hui , Yuan Ling-Qing , Wu Xian-Ping , Zhou Hou-De , Liao Er-Yuan
Published: September 2006

Our study indicates that recombinant adiponectin induced RANKL and inhibited OPG expression in human osteoblasts through the AdipoR1/p38 MAPK pathway, and these responses contributed to the adiponectin-induced osteoclasts formation in the co-culture of osteoblast and peripheral blood monocytes systems. These findings showed that adiponectin increased osteoclast formation indirectly through stimulating RANKL and inhibiting OPG production in osteoblasts. It also suggests the pharmacological nature of recombinant adiponectin that indirectly induces osteoclasts formation.

Introduction: Recently, adiponectin has emerged as an element in the regulation of bone metabolism, but the mechanism remains. This study was undertaken to investigate the action of adiponectin on osteoclastogenesis through revealing RANKL and osteoprotegerin (OPG) expression in osteoblasts and osteoclast formation.

Materials and Methods: Real-time quantitative PCR and ELISA were used to detect RANKL and OPG mRNA and protein expression in cultured human osteoblasts. The involved signal pathway was studied using mitogen-activated protein kinase (MAPK) inhibitor and adiponectin receptor 1 (AdipoR1) siRNA. The effects of recombinant adiponectin on osteoclasts formation also were examined in the co-culture systems of osteoblast and peripheral blood monocytes (PBMCs) systems or purified CD14 + PBMCs cultures.

Results: Our study showed that recombinant adiponectin induced RANKL and inhibited OPG mRNA expression in human osteoblasts in a dose- and time-dependent manner. Adiponectin also increased soluble RANKL and decreased OPG secretion in osteoblasts conditioned media. Suppression of AdipoR1 with siRNA abolished the adiponectin-regulated RANKL and OPG mRNA expression in osteoblasts. Furthermore, pretreatment of osteoblasts with the MAPK inhibitor SB203580 abolished adiponectin-regulated RANKL and OPG mRNA expression. Adiponectin induced osteoclast formation in the co-culture systems of osteoblast and PBMCs systems, and OPG entirely blocked this response. However, adiponectin had no direct effect on the differentiation of osteoclast precursor purified CD14 + PBMCs.

Conclusions: These data indicate that recombinant adiponectin induced RANKL and inhibited OPG expression in human osteoblasts through the AdipoR1/p38 MAPK pathway, and these responses contributed to the adiponectin-induced osteoclast formation in the co-culture of osteoblast and PBMCs systems. These findings showed that adiponectin increased osteoclast formation indirectly through stimulating RANKL and inhibiting OPG production in osteoblasts. It suggests the pharmacological nature of recombinant adiponectin that indirectly induces osteoclasts formation.
BMD and Risk of Hip and Nonvertebral Fractures in Older Men:A Prospective Study and Comparison With Older Women
Authors: Cummings Steven R , Cawthon Peggy M , Ensrud Kristine E , Cauley Jane A , Fink Howard A , Orwoll Eric S
Published: September 2006

In a prospective study of 5384 older men, hip BMD was a very strong predictor of hip fracture, much stronger than spine BMD. The relationship between hip BMD and hip fracture risk seemed to be stronger than observed in a large prospective study of women. Hip BMD is an excellent test for predicting fracture risk in men.

Introduction: There have been few studies of the relationship between BMD and risk of fractures in men and none for the association between lumbar spine BMD and risk of hip and nonvertebral fractures. There is also controversy about whether the associations between BMD and risk of fracture are the same in men and women.

Materials and Methods: We measured proximal femur and lumbar spine BMD in 5384 men, ≥65 years of age. We compared the results to the very similar cohort of 7871 women ≥65 of age. During 4.4 years of 99% complete follow-up, we validated 317 nonvertebral (59 hip) fractures in men and 1169 nonvertebral (208 hip) fractures in women.

Results: Total hip BMD was very strongly associated with risk hip fracture in men (3.2-fold increased risk per sex-specific SD decrease in BMD; 95% CI, 2.4–4.1). The association was stronger than observed in SOF (2.1; 95% CI, 1.8, 2.4; p < 0.001 for interaction). Among the men, lumbar spine BMD was weakly associated with risk of hip fracture (relative risk [RR] per sex-specific SD decrease in BMD: 1.5; 95% CI, 1.2, 2.0). The association between total hip BMD and risk of nonvertebral fractures was somewhat stronger for men (RR = 1.6; 95% CI, 1.5, 1.8) than found for women (p = 0.01 for interaction). The risk of nonvertebral fracture was substantially higher in women than in men for all T scores of hip BMD, regardless of whether sex-specific or female reference values were used.

Conclusions: Hip BMD is strongly associated with risk of nonvertebral, and especially hip fracture, in older men. These associations are at least as strong as in women. As in women, lumbar spine BMD in men is only weakly associated with risk of hip fracture. Regardless of whether sex-specific or female reference values were used, T scores indicated different risks of fractures in men than in women.