bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isolation and characterization of human gingival microvascular endothelial cells
Authors: DeCarlo A. A. , Cohen J. A. , Aguado A. , Glenn B. 
Published: January 2008

Background and Objective:  Endothelial cells have a substantial role in maintaining vascular homeostasis, and their dysregulation can contribute to the development of pathology. The plasminogen activators and their inhibitors may, arguably, be the single most important proteolytic system of the endothelium for vascular maintenance by controlling plasminogen activation and other proteolytic cascades that impact on clotting, hemodynamics, angiogenesis and the character of the vascular wall. In chronic periodontal disease, significant changes to the microvasculature occur in association with the severity of the disease. Investigation of the role played by endothelial cells in periodontal health and disease has been limited to in situ immunolocalization or to the use of endothelial cells of nongingival origin, such as human umbilical vein endothelial cells. The objective of this research was to establish a replicable protocol for isolating microvascular endothelial cells from the gingiva.Material and Methods:  From inflamed gingiva, isolated cells were characterized by morphology, the expression of factor VIII‐related antigen, the expression of UEA‐1 ligand, the uptake of acetylated low‐density lipoprotein, network formation on Matrigel, and by the expression levels of urokinase plasminogen activator, tissue plasminogen activator, plasminogen activator inhibitor‐1 and collagen IV.Results and Conclusion:  Gingival endothelial cells were most readily obtained from inflamed gingival tissues, and these endothelial cells, when isolated by the protocol established herein, demonstrated endothelial characteristics and constitutively secreted plasminogen activators and plasminogen activator inhibitor‐1 in culture.
Cementum–periodontal ligament complex regeneration using the cell sheet technique
Authors: Flores M. Gomez , Hasegawa M. , Yamato M. , Takagi R. , Okano T. , Ishikawa I. 
Published: January 2008

Background and Objective:  In the present study we evaluated if a multilayered human periodontal ligament cell sheet could reconstruct the physiological architecture of a periodontal ligament–cementum complex.Material and methods:  Human periodontal ligament cells were isolated and then cultured in dishes coated with a temperature‐responsive polymer to allow cell detachment as a cell sheet. In the control group, human periodontal ligament cells were cultured in Dulbecco’s modified Eagle’s minimal essential medium containing 10% fetal bovine serum and 1% antibiotics. In the experimental group, human periodontal ligament cells were cultured in Dulbecco’s modified Eagle’s minimal essential medium and osteodifferentiation medium containing dexamethasone, ascorbic acid and β‐glycerophosphate. After 3 wk, scanning electron microscopy was carried out, in addition to staining for alkaline phosphatase activity and for calcium (using the Von Kossa stain). Then human periodontal ligament cell sheets were multilayered and placed onto dentin blocks. The constructs were transplanted subcutaneously into the back of immunodeficient rats. At 1 and 6 wk after transplantation, the animals were killed. Demineralized tissue sections were stained using hematoxylin and eosin, and Azan, and then analyzed.Results:  After 3 wk of culture in osteodifferentiation medium, human periodontal ligament cells produced mineral‐like nodules and also showed positive staining for alkaline phosphatase, calcium (Von Kossa) and mRNA expression of type I collagen. By contrast, in the control group only weak alkaline phosphatase staining was observed, the Von Kossa stain was negative and there was no mRNA expression of type I collagen. Six weeks after transplantation with human periodontal ligament cells cultured in osteodifferentiation medium, most of the dentin surfaces showed a newly immature cementum‐like tissue formation and periodontal ligament with perpendicular orientation inserted into the newly deposited cementum‐like tissue.Conclusion:  This study suggests that the multilayered temperature‐responsive culture system can be used as a novel strategy for periodontal regeneration. The human periodontal ligament cell sheet technique may be applicable for regeneration of the clinical periodontal ligament–cementum complex.
Macrophage tolerance response to Aggregatibacter actinomycetemcomitans lipopolysaccharide induces differential regulation of tumor necrosis factor‐α, interleukin‐1β and matrix metalloproteinase 9 secretion
Authors: Tanabe S‐I , Grenier D 
Published: January 2008

Background and Objective:  The lipopolysaccharide of Aggregatibacter actinomycetemcomitans, a potent stimulator of the immune system, induces the secretion of inflammatory mediators that modulate periodontal tissue destruction. In this study, we investigated the tolerance response of human macrophages to stimulation with A. actinomycetemcomitans lipopolysaccharide.Material and Methods:  U937 monocytes were differentiated into adherent macrophage‐like cells by treatment with phorbol myristic acid. Macrophage‐like cells were then pretreated for 24 h with either 0.01 or 0.1 μg/mL LPS A. actinomycetemcomitans. Culture medium supernatants were removed and cells were restimulated with LPS at 1 μg/mL. Cell‐free supernatants were collected after 24 h of stimulation and analyzed by ELISA for TNF‐α, IL‐1β, IL‐6, IL‐8, PGE2 and MMP‐9.Results:  Phorbol myristic acid‐differentiated U937 macrophages treated with low doses of lipopolysaccharide developed tolerance to subsequent lipopolysaccharide treatments, resulting in significantly reduced secretion of tumor necrosis factor‐α. However, this tolerance response was associated with increased secretion of interleukin‐1β and matrix metalloproteinase 9, whereas the secretion of interleukin‐6, interleukin‐8 and prostaglandin E2 was unaffected. Phosphatidylinositol‐3′‐kinase inhibitors added during the tolerance‐induction period markedly attenuated the increase in interleukin‐1β secretion but had no effect on tumor necrosis factor‐α.Conclusion:  This study showed that A. actinomycetemcomitans lipopolysaccharide can induce a tolerance response in macrophages that alters the secretion of two important inflammatory mediators as well as of the tissue‐degrading enzyme matrix metalloproteinase‐9. This phenomenon may play a role in modulating the host inflammatory response and the progression of periodontitis.
Attitudes toward Dental Appearance in 50‐ and 60‐Year‐Old Subjects Living in Sweden
Authors: CARLSSON GUNNAR E. , JOHANSSON ANDERS , JOHANSSON ANN‐KATRIN , ORDELL SVEN , EKBÄCK GUNNAR , UNELL LENNART 
Published: January 2008

ABSTRACTBackground:  Attitudes toward the importance of general appearance have varied much, not only over time but also among groups of individuals of different age and other characteristics. Whether the situation is similar regarding dental appearance does not seem to have been studied.Purpose:  The aim was to study the differences in attitudes toward dental appearance between two large samples of 50‐ and 60‐year‐old subjects.Materials and Methods:  Identical questionnaires were sent to all subjects born in 1942 and 1952 living in two Swedish counties in 2002 (N=17,444; N50=8,881, N60=8,563). The final response rate was 72.2% (N=12,599). In this study, responses to four statements on the importance of dental appearance have been analyzed with respect to gender and age.Results:  Many of the responses to the four statements differed with gender and age. To the first statement (“To have beautiful and perfect teeth is very important for how you are treated by other people”), 73% agreed at age 60 compared with 64% at age 50 (p < 0.001). Approximately 90% of the subjects agreed with the second statement (“Minor esthetic imperfections of the teeth have no importance, only they function well”). Logistic regression indicated that several variables were significantly associated with the statements. Besides age and gender, education and self‐assessed dental problems were most important.Conclusion:  Attitudes toward the importance of dental appearance differed both between genders and age groups in these population samples living in Sweden.CLINICAL SIGNIFICANCEThe varying attitudes toward dental appearance in the population must be acknowledged in treatment decisions.(J Esthet Restor Dent 20:46–56, 2008)
On the nature of precursors in the radio pulsar profiles
Authors: Petrova S. A. 
Published: January 2008

Abstract
In the average profiles of several radio pulsars, the main pulse is accompanied by the preceding component. This so-called precursor is known for its distinctive polarization, spectral and fluctuation properties. Recent single-pulse observations hint that the sporadic activity at the extreme leading edge of the pulse may be prevalent in pulsars. We for the first time propose a physical mechanism of this phenomenon. It is based on the induced scattering of the main pulse radiation into the background. We show that the scattered component is directed approximately along the ambient magnetic field and, because of rotational aberration in the scattering region, appears in the pulse profile as a precursor to the main pulse. Our model naturally explains high linear polarization of the precursor emission, its spectral and fluctuation peculiarities as well as suggests a specific connection between the precursor and the main pulse at widely spaced frequencies. This is believed to stimulate multifrequency single-pulse studies of intensity modulation in different pulsars.
Outflowing atomic and molecular gas at z∼ 0.67 towards 1504 + 377
Authors: Kanekar Nissim , Chengalur Jayaram N. 
Published: January 2008

Abstract
We report the detection of OH 1667-MHz and wide H i 21-cm absorption at z∼ 0.67 towards the red quasar 1504 + 377, with the Green Bank Telescope and the Giant Metrewave Radio Telescope. The H i 21-cm absorption extends over a velocity range of ∼600 km s−1 blueward of the quasar redshift (z= 0.674), with the new OH 1667-MHz absorption component at ∼ −430 km s−1, nearly coincident with earlier detections of millimetre-wave absorption at z∼ 0.6715. The atomic and molecular absorption appear to arise from a fast gas outflow from the quasar, with a mass outflow rate and a molecular hydrogen fraction . The radio structure of 1504 + 377 is consistent with the outflow arising as a result of a jet–cloud interaction, followed by rapid cooling of the cloud material. The observed ratio of HCO+ and OH column densities is ∼20 times higher than typical values in Galactic and high-z absorbers. This could arise because of small-scale structure in the outflowing gas on sub-parsec scales, which would also explain the observed variability in the H i 21-cm line.
H i power spectrum of the spiral galaxy NGC 628
Authors: Dutta Prasun , Begum Ayesha , Bharadwaj Somnath , Chengalur Jayaram N. 
Published: January 2008

Abstract
We have measured the H i power spectrum of the nearly face-on spiral galaxy NGC 628 (M74) using a visibility-based estimator. The power spectrum is well fitted by a power law P(U) =AUα, with α=−1.6 ± 0.2 over the length-scale 800 pc to 8 kpc. The slope is found to be independent of the width of the velocity channel. This value of the slope is a little more than one in excess of what has been seen at considerably smaller length-scales in the Milky Way, the Small Magellanic Cloud, the Large Magellanic Cloud (LMC) and the dwarf galaxy DDO 210. We interpret this difference as indicating a transition from three-dimensional turbulence at small scales to two-dimensional turbulence in the plane of the galaxy disc at length-scales larger than the H i scaleheight of the galaxy. The slope measured here is similar to that found at large scales in the LMC. Our analysis also places an upper limit to the galaxy scaleheight at 800 pc.
Influence of AGN outbursts on the surrounding galaxies
Authors: Fujita Yutaka 
Published: January 2008

Abstract
We study the influence of a strong AGN outburst on the surrounding galaxies. The AGN is assumed to reside in a group of galaxies, and an outburst excites a shock wave in the hot gas in the group. We calculate the impact of the shock wave on the galaxies. We find that if the energy of the outburst is extremely large (EAGN∼ 6 × 1061 erg) as the one recently observed in clusters, the impact is strong enough to strip the cold interstellar medium in the disc of the galaxies in the inner region of the group. Moreover, even in the outer region of the group, the warm gas in the halo of the galaxies would be stripped, even if the energy of the outburst is ∼6 × 1060 erg. These would decrease star formation activity of the galaxies. If these galaxies fall into the group centre through dynamical friction and their interstellar medium is the fuel of the supermassive black hole in the AGN, the outburst would serve as feedback. While this mechanism works only when EAGN is extremely large, such outbursts have not been observed in groups at low redshift; it would work at high redshift rather than at low redshift.
Alcohol and Drug Use in Rural Colonias and Adjacent Urban Areas of the Texas Border
Authors: Spence Richard T. , Wallisch Lynn S. 
Published: January 2008

ABSTRACT:
Context: Little is known about substance use and treatment utilization in rural communities of the United States/Mexico border. Purpose: To compare substance use and need and desire for treatment in rural colonias and urban areas of the border. Methods: Interviews were conducted in 2002‐2003 with a random sample of adults living in the lower Rio Grande Valley of Texas, adjacent to the Mexican border. The present analysis compares responses from 400 residents of rural colonias to those of 395 residents of cities and towns in the same geographic region. Findings: While the prevalence of drug use and drug‐related problems was similar in both areas, binge drinking and alcohol dependence were higher in rural colonias than in urban areas and remained so after taking demographic and neighborhood variables into account. An increase in illicit drug use and substance‐related problems in rural but not urban areas was seen when comparing results from this study with those of a previous survey conducted in 1996. The percentage of adults in potential need of treatment and the percentage motivated to seek it were similar in both urban and rural areas. However, colonia residents were more likely than their urban counterparts to be recent immigrants and to have lower incomes and educational attainment, factors that can increase the barriers they face in getting needed services. Conclusions: Rural areas are “catching up” with urban areas in problematic substance use. Given the potential barriers to accessing treatment services in rural areas, efforts should be focused on reaching those residents.
Illicit Drug Use and the Social Context of HIV/AIDS in Alabama's Black Belt
Authors: Lichtenstein Bronwen 
Published: January 2008

ABSTRACT:
Context: The rural Black Belt of Alabama is among the poorest areas of the nation. Poverty, lack of health infrastructure, and health disparities involving HIV/AIDS and other diseases reflect the lower life expectancy of people in the region. The Black Belt region has the highest HIV rates in rural America. Purpose: Using Alabama as a case example, the paper describes the role of illicit drug use in pathways to HIV transmission in the Black Belt and examines the relationship between drug use and social context with respect to HIV/AIDS disparities in the region. Methods: Published research and national and state data were triangulated for information on interactions between illicit drug use, social context, and HIV/AIDS. Findings: Illicit drug use is implicated in HIV risk in Alabama's Black Belt, but less so than in other parts of the nation. Published research suggests that the impetus for drug use involves status seeking in the context of heterosexual contact and economic disparities. HIV transmission in Alabama's Black Belt speaks to the tyranny of small places; that is, the risk of HIV/AIDS occurs in geographically bounded areas with a history of racial homogeneity, historically high rates of sexually transmitted infections, and clustered sexual networks in this isolated region. Conclusions: Social context is an important correlate of HIV risk in the Black Belt. The role of drug use in HIV risk is secondary to social‐contextual factors involving rural isolation, racial homogeneity, and the racial disparities of the region.
Growth of the tufted‐tailed rat
Authors: RANDRIANJAFY Vololomboahangy R. , RAMILIJAONA Olga , RAKOTONDRAVONY Daniel 
Published: January 2008

Abstract Eliurus myoxinus (Rodentia: Nesomyidae, Nesomyinae) is one of the four species of endemic Malagasy rodents known to exist in the Ankarafantsika National Park, northwestern Madagascar. In order to study growth parameters and to determine at which age E. myoxinus commences breeding, we used two different techniques: captive breeding and a capture‐mark‐release field program in the species' natural habitat. The data collected on the breeding of E. myoxinus in captivity demonstrated that females can give birth to a litter of up to four pups, with up to four litters per calendar year. Reproduction of E. myoxinus was more likely to be continuous in captivity than under natural habitat conditions. If parturition failed, then post‐partum mating occurred. Pups had a rapid linear growth phase from birth until 1 month of age. Between 1.5 and 2 months of age, the growth rate continued to increase, but then decreased at around the time of weaning, which occurred by 3.5 months of age. The successive maximum method of age determination showed that individuals at the “young” stage had an average body length of 90 mm and a weight of 30 g and were between 1.5 and 2 months old. The greatest variation in measurements of juveniles occurred at the age of 3.5 months. At this stage, sub‐adults resembled adults but their external genitalia were not well developed. Individuals were classified as adults if they had reached a body length of 110 mm and a body weight of 40 g. This occurred at more than 4.5 months of age when the animals were generally reproductively active. The Vo n Bertalanffy method indicated that individuals reach the adult stage by 6 to 7 months. Males grew more rapidly than females, reaching adulthood by 5.5 months of age, whereas females only reached adulthood several weeks later. This species is polygamous. The sex ratio of pups at birth favored females by approximately 3:1. The higher proportion of female pups at birth may represent a survival strategy of this species, possibly associated with ecological conditions.
Anti‐fertility effect of levonorgestrel and quinestrol in Brandt's voles (Lasiopodomys brandtii)
Authors: ZHAO Meirong , LIU Ming , LI Dong , WAN Xinrong , HINDS Lyn A. , WANG Yanling , ZHANG Zhibin 
Published: January 2008

AbstractThe combination of levonorgestrel and quinestrol (EP‐1) has been shown to have anti‐fertility effects on several wild rodents, but the mechanism underlying these effects is poorly understood. We investigated the effects of EP‐1 and each of its components, levonorgestrel (P) and quinestrol (E), on the fertility of Brandt's voles (Lasiopodomys brandtii) by using a gastric gavage method. The doses for EP‐1, E and P were 1, 0.34 and 0.66 mg/kg body weight, respectively. Male voles (n = 98) were treated daily for 5 or 14 days, then the testes and epididymides were collected, weighed and examined histologically at 30 (D30), 60 (D60) or 90 (D90) days after the end of treatment. Four males were allowed to mate with normal females at D90. Female voles (n = 75) were treated for 3 days and a further 3 days after a 7‐day interval. The uteri and ovaries were weighed and examined histologically at 15 (D15), 30 (D30) or 75 (D75) days after the end of treatment. Each of three females were mated with fertile males at D30 and D75, respectively. Our results indicated that quinestrol (E) significantly decreased the sperm numbers in the testes as well as the weight of the testes and epididymides, with both of these tissues showing obvious structural abnormalities, and significantly reduced the litter size and the pup weight for females mated with males of the E treatment group. For female voles, treatment with E, P or EP‐1 resulted in no marked influence on the fertility status. These data indicate that quinestrol (E) alone has a significant anti‐fertility effect on male Brandt's voles, but is ineffective in combination with levonorgestrel (P).
Adaptation as a potential response to sea‐level rise: a genetic basis for salinity tolerance in populations of a coastal marsh fish
Authors: Purcell Kevin M. , Hitch Alan T. , Klerks Paul L. , Leberg Paul L. 
Published: January 2008

AbstractRelative sea‐level rise is resulting in the intrusion of saline waters into marshes historically dominated by fresh water. Saltwater intrusions can potentially affect resident marsh species, especially when storm‐related tidal surges cause rapid changes in salinity. We examined the role of historical salinity exposure on the survival of Gambusia affinis from two locations in coastal Louisiana. At each location, we sampled fish populations from fresh, intermediate and brackish marshes. Individuals were then exposed to a salinity of 25‰ and survival time was measured. We found that fish from brackish and intermediate marshes had an increased tolerance to salinity stress relative to fish from freshwater environments. We then tested the descendents of fish from the fresh and brackish marshes, reared for two generation in fresh water, to determine if there was a genetic basis for differential survival. We found that descendents of individuals from brackish marshes showed elevated survivals relative to the descendents of fish with no historical exposure to salinity. The most reasonable mechanism to account for the differences in survival relative to historical exposure is genetic adaptation, suggesting that natural selection may play a role in the responses of resident marsh fishes to future increases in salinity.
Introgression and dispersal among spotted owl (Strix occidentalis) subspecies
Authors: Funk W. Chris , Forsman Eric D. , Mullins Thomas D. , Haig Susan M. 
Published: January 2008

AbstractPopulation genetics plays an increasingly important role in the conservation and management of declining species, particularly for defining taxonomic units. Subspecies are recognized by several conservation organizations and countries and receive legal protection under the US Endangered Species Act (ESA). Two subspecies of spotted owls, northern (Strix occidentalis caurina) and Mexican (S. o. lucida) spotted owls, are ESA‐listed as threatened, but the California (S. o. occidentalis) spotted owl is not listed. Thus, determining the boundaries of these subspecies is critical for effective enforcement of the ESA. We tested the validity of previously recognized spotted owl subspecies by analysing 394 spotted owls at 10 microsatellite loci. We also tested whether northern and California spotted owls hybridize as suggested by previous mitochondrial DNA studies. Our results supported current recognition of three subspecies. We also found bi‐directional hybridization and dispersal between northern and California spotted owls centered in southern Oregon and northern California. Surprisingly, we also detected introgression of Mexican spotted owls into the range of northern spotted owls, primarily in the northern part of the subspecies’ range in Washington, indicating long‐distance dispersal of Mexican spotted owls. We conclude with a discussion of the conservation implications of our study.