bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transcellular transport of CCL2 across brain microvascular endothelial cells
Authors: Ge Shujun , Song Li , Serwanski David R. , Kuziel William A. , Pachter Joel S. 
Published: October 2007

AbstractThe means by which the chemokine CCL2 produced in the brain parenchyma can recruit leukocytes lying behind the highly impervious endothelium of the blood–brain barrier (BBB) has remained a paradox. As other chemokines have been evidenced to stimulate their own synthesis and release by peripheral microvascular endothelial cells, and/or undergo transcytosis in the abluminal‐to‐luminal direction, we determined whether CCL2 experiences similar fates across brain microvascular endothelial cells (BMEC). Using cultured BMEC as a paradigm of the BBB, it was observed that exogenous unlabeled CCL2 actually depressed the release of endogenous CCL2, and further caused diminished CCL2 mRNA levels in these cells. On the other hand, exogenous125I‐labeled CCL2 exhibited transport across BMEC in a manner that was sensitive to temperature, competition by excess unlabeled CCL2 but not unlabeled CCL3, knockdown of caveolin‐1/caveolae, and elimination of the cognate CCL2 receptor CCR2. These results implied a facet of CCL2 transport by a transcellular mechanism partly involving binding of CCL2 to CCR2, and subsequent transfer to caveolae vesicles for transcytosis. This notion was supported by double‐label immuno‐electronmicroscopy, which revealed co‐localization of caveolin‐1 with exogenous CCL2, during this chemokine’s transit across BMEC. Collectively, these findings provide a rationale by which CCL2, deposited on the abluminal side of the brain microvasculature during inflammatory episodes, can be relayed across the BBB to foster leukocyte recruitment.
C‐terminal splice variants of the μ‐opioid receptor: existence, distribution and functional characteristics
Authors: Oldfield Sue , Braksator Ellen , Rodriguez‐Martin Ivan , Bailey Chris P. , Donaldson Lucy F. , Henderson Graeme , Kelly Eamonn 
Published: October 2007

AbstractThe distribution of the mRNA of different C‐terminal splice variants of the μ‐opioid receptor in rat CNS was assessed by RT‐PCR. The mRNA species for MOR1, MOR1A and MOR1B were readily detectable and distributed widely throughout the rat CNS, with levels of MOR1 and MOR1A mRNA being overall greater than for MOR1B. We did not find convincing evidence that significant levels of MOR1C, MOR1C1, MOR1C2 and MOR1D are present in rat CNS. To examine possible differences in the agonist‐induced regulation of MOR1, MOR1A and MOR1B, we expressed these constructs in HEK293 cells along with G‐protein‐coupled inwardly rectifying K+ channel subunits and measured the rate and extent of desensitisation of (d‐Ala2,N‐Me‐Phe4,glycinol5)‐enkephalin (DAMGO)‐ and morphine‐induced G‐protein‐coupled inwardly rectifying K+ currents. Morphine‐induced desensitisation was rapid for all three splice variants (t½: 1.2–1.7 min) but DAMGO‐induced desensitisation was significantly slower for MOR1B (t½ 4.2 min). Inhibition of endocytosis by expression of a dynamin‐dominant negative mutant increased the rate of DAMGO‐induced desensitisation of MOR1B. These data show that some splice variants of μ‐opioid receptor are widely expressed in rat CNS but question the existence of others that have been reported in the literature. In addition, whereas the rate of desensitisation of MOR1 and MOR1A is agonist‐independent, that for MOR1B is agonist‐dependent.
Transcriptional instability is not a universal attribute of aging
Authors: Warren Luigi A. , Rossi Derrick J. , Schiebinger Geoffrey R. , Weissman Irving L. , Kim Stuart K. , Quake Stephen R. 
Published: October 2007

SummaryIt has been proposed that cumulative somatic mutations contribute to the aging process by disrupting the transcriptional networks that regulate cell structure and function. Experimental support for this model emerged from a recent study of cardiomyocytes that showed a dramatic increase in the transcriptional heterogeneity of these long‐lived postmitotic cells with age. To determine if regulatory instability is a hallmark of aging in renewing tissues, we evaluated gene expression noise in four hematopoietic cell types: stem cells, granulocytes, naïve B cells and naïve T cells. We used flow cytometry to purify phenotypically equivalent cells from young and old mice, and applied multiplexed quantitative reverse transcription–polymerase chain reaction to measure the copy number of six different mRNA transcripts in 324 individual cells. There was a trend toward higher transcript levels in cells isolated from old animals, but no significant increase in transcriptional heterogeneity with age was found in the surveyed populations. Flow cytometric analysis of membrane protein expression also indicated that cell‐to‐cell variability was unaffected by age. We conclude that large‐scale regulatory destabilization is not a universal concomitant of aging, and may be of significance as an aging mechanism primarily in nonrenewing tissues.
Vascular superoxide and hydrogen peroxide production and oxidative stress resistance in two closely related rodent species with disparate longevity
Authors: Csiszar Anna , Labinskyy Nazar , Zhao Xiangmin , Hu Furong , Serpillon Sabrina , Huang Zhishan , Ballabh Praveen , Levy Richard J. , Hintze Thomas H. , Wolin Michael S. , Austad Steven N. , Podlutsky Andrej , Ungvari Zoltan 
Published: October 2007

SummaryVascular aging is characterized by increased oxidative stress, impaired nitric oxide (NO) bioavailability and enhanced apoptotic cell death. The oxidative stress hypothesis of aging predicts that vascular cells of long‐lived species exhibit lower production of reactive oxygen species (ROS) and/or superior resistance to oxidative stress. We tested this hypothesis using two taxonomically related rodents, the white‐footed mouse (Peromyscus leucopus) and the house mouse (Mus musculus), that show a more than twofold difference in maximum lifespan potential (MLSP = 8 and 3.5 years, respectively). We compared interspecies differences in endothelial superoxide () and hydrogen peroxide (H2O2) production, NAD(P)H oxidase activity, mitochondrial ROS generation, expression of pro‐ and antioxidant enzymes, NO production, and resistance to oxidative stress‐induced apoptosis. In aortas of P. leucopus, NAD(P)H oxidase expression and activity, endothelial and H2O2 production, and ROS generation by mitochondria were less than in mouse vessels. In P. leucopus, there was a more abundant expression of catalase, glutathione peroxidase 1 and hemeoxygenase‐1, whereas expression of Cu/Zn‐SOD and Mn‐SOD was similar in both species. NO production and endothelial nitric oxide synthase expression was greater in P. leucopus. In mouse aortas, treatment with oxidized low‐density lipoprotein (oxLDL) elicited substantial oxidative stress, endothelial dysfunction and endothelial apoptosis (assessed by TUNEL assay, DNA fragmentation and caspase 3 activity assays). According to our prediction, vessels of P. leucopus were more resistant to the proapoptotic effects of oxidative stressors (oxLDL and H2O2). Primary fibroblasts from P. leucopus also exhibited less H2O2‐induced DNA damage (comet assay) than mouse cells. Thus, increased lifespan potential in P. leucopus is associated with a decreased cellular ROS generation and increased oxidative stress resistance, which accords with the prediction of the oxidative stress hypothesis of aging.
Indications for Stent Placement in a Dialysis Access
Authors: Rasmussen Randall L. , Feldman David , Beathard Gerald , Rubin Jack E. 
Published: October 2007

AbstractNKF‐K/DOQI Clinical Practice Guidelines for Vascular Access, Guideline 6, Treatment of Arteriovenous Graft Complications, limit the number of potential indications for stent deployment that may extend the life of the dialysis access (1). The guidelines include recommendations for the treatment of dialysis access stenosis, central vein stenosis, pseudoaneurysms and for angioplasty‐associated vascular rupture that cannot be successfully treated by PTA. However, stenting may need to be considered in certain settings falling outside these guidelines.
Special Report: Dialysis Surveillance Report: National Healthcare Safety Network (NHSN)—Data Summary for 2006
Authors: Klevens R. Monina , Edwards Jonathan R. , Andrus Mary L. , Peterson Kelly D. , Dudeck Margaret A. , Horan Teresa C. ,   and the NHSN Participants in Outpatient Dialysis Surveillance
Published: October 2007

AbstractThirty‐two outpatient hemodialysis providers in the United States voluntarily reported 3699 adverse events to the Centers for Disease Control and Prevention (CDC) National Healthcare Safety Network (NHSN) during 2006. These providers were previously enrolled in the Dialysis Surveillance Network. The pooled mean rates of hospitalization among patients with arteriovenous fistulas, grafts, permanent and temporary central venous catheters were 7.7, 9.2, 15.7, and 34.7 per 100 patient‐months, respectively. For bloodstream infection the pooled mean rates were 0.5, 0.9, 4.2, and 27.1 per 100 patient‐months in these groups. Among the 599 isolates reported, 461 (77%) represented access‐associated blood stream infections in patients with central lines, and 138 (23%) were in patients with fistulas or grafts. The microorganisms most frequently identified were common skin contaminants (e.g., coagulase‐negative staphylococci). In 2007, enrollment in NHSN opened to all providers of outpatient hemodialysis. Specific information is available at http://www.cdc.gov/ncidod/dhqp/nhsn_FAQenrollment.html.
Influence of Fixation Mode and Superstructure Span upon Strain Development of Implant Fixed Partial Dentures
Authors: Karl Matthias , Wichmann Manfred G. , Winter Werner , Graef Friedrich , Taylor Thomas D. , Heckmann Siegfried M. 
Published: October 2007

Abstract Purpose: Implant‐borne fixed partial dentures (FPDs) should fit passively in order to avoid complications ranging from screw loosening to loss of osseointegration. The aim of this study was to measure the strain development of three‐unit and five‐unit screw‐ and cement‐retained implant‐supported FPDs. Additionally, the influence of the parameters retention mechanism and FPD span were evaluated. Materials and Methods: Three Straumann implants were anchored in a measurement model based on a real‐life patient situation and strain gauges (SGs) were fixed mesially and distally adjacent to the implants and on the pontics of the superstructures. During cement setting and screw fixation of 40 implant FPDs (10 samples from each group: three‐unit cementable; five‐unit cementable; three‐unit screw‐retained; five‐unit screw‐retained), strain development was recorded. For statistical analysis, multivariate two‐sample tests were performed with the level of significance set at p= 0.1. Results: The mean strain values for the four FPD groups at the different SG sites ranged from 26.0 to 637.6 μm/m. When comparing the four groups, no significant differences in strain magnitude could be detected. Similarly, a comparison of the two FPD spans revealed no significant difference (p= 0.18 for cementable FPDs; p= 0.22 for screw‐retained FPDs). A comparison of the two fixation modes also revealed no significant difference (p= 0.67 for three‐unit FPDs; p= 0.25 for five‐unit FPDs). Conclusion: FPD span and retention mechanism appear to have only a minor influence on strain development in implant FPDs. As implant‐supported restorations have proven to be successful over time, the question arises as to whether an “absolute” passive fit is a prerequisite for successful implant restorations.
Occlusal Changes Following Posterior Tooth Loss in Adults. Part 3. A Study of Clinical Parameters Associated with the Presence of Occlusal Interferences Following Posterior Tooth Loss
Authors: Craddock Helen L. 
Published: October 2007

Abstract Purpose: Tooth positional changes following posterior tooth loss may alter arch forms and occlusal planes. This may result in the development of occlusal interferences. The purpose of this study was to determine clinical parameters associated with the presence of retruded contact position (RCP) contacts and occlusal interferences associated with posterior tooth loss. Materials and Methods: Diagnostic casts of 100 patients with at least one unopposed posterior tooth and 100 control patients were scanned and analyzed to record clinical parameters described in the earlier publications in this series. Clinical examinations identified the presence of RCP contacts and occlusal interferences. Five generalized linear models were developed to investigate the parameters associated with presence of RCP contacts, protrusive interferences, working side interferences, and nonworking side interferences. Results: RCP contacts were associated with the degree of supraeruption of the unopposed tooth and the presence of other types of interferences. Protrusive interferences were associated with the presence and position of a tooth distal to the extraction site and the presence of other types of interference. Working side interferences were associated with tipping of the tooth mesial to the extraction site and the presence of other interferences. Nonworking side interferences were associated with the presence of other types of interference only. Conclusion: Unopposed posterior teeth are more likely to be involved in RCP contacts or interferences than their matched controls. Many teeth were involved in multiple interferences, and there appears to be a number of interrelationships between these. Initial RCP contacts have associations with the extent of supraeruption of the unopposed teeth. The presence and position of the teeth distal to extraction sites was significant when modeling protrusive interferences. Protrusive interferences are more prevalent where the site of tooth loss was bounded. Mesial tipping of the teeth distal to extraction sites reduced this effect. Working side interferences were associated with tipping of teeth mesial to the site of tooth loss. No associations between patient or tooth factors were found for nonworking side interferences, and the only association found for these interferences were with protrusive interferences at the sites.
Placement and Restoration of Dental Implants in a Patient with Paget's Disease in Remission: Literature Review and Clinical Report
Authors: Rasmussen Jonathan M. , Hopfensperger Matthew L. 
Published: October 2007

AbstractPaget's disease is a disorder of bone that results in the replacement of normal bone with highly vascularized, low density bone. The diminished bone quality associated with Paget's disease is a relative contraindication to the use of dental implants, as it interferes with achievement of osseointegration. There is no current literature on the success of dental implants in patients with Paget's disease. Furthermore, there is no current literature on dental implant success in patients with remissive Paget's disease or in bone that appears to be unaffected by the disease in patients with Paget's. This case report follows the treatment of a patient with a partially edentulous maxilla and mandible (ACP PDI Classification III) who presented with remissive Paget's disease. Definitive treatment included the placement of four endosseous implants used to retain full veneer crowns. Despite the radiographic appearance of adequate bone quality, upon surgical placement it was discovered that the quality of bone was poor, yet implant survival was achieved through careful surgical management and rigid splinting of some of the endosseous implants.
Restoration of the Severely Compromised Maxilla Using the Multi‐Cup Denture
Authors: Engelmeier Robert L. , Gonzalez Maria L. , Harb Maribel 
Published: October 2007

AbstractAmong the millions of edentulous Americans, a persistent minority have not been able tolerate wearing dentures. Complicating factors may have precluded surgical intervention with grafts or dental implants to improve the physical and anatomic limitations of these unfortunate patients. A heat‐cured polymer liner containing multiple small suction cups has been used for decades to successfully restore many such debilitated individuals. Two middle‐aged female patients with edentulous maxillae and near fully dentate mandibles had both reached a point where they could no longer retain a maxillary complete denture, or function with it. Both had experienced multiple failed surgical attempts to improve their situations. They were both successfully restored with maxillary complete dentures containing heat‐cured silicone liners with multiple small suction cups. Two young female maxillectomy patients had significant difficulties wearing maxillary obturators due to defect size and absence of defect undercuts. One had an edentulous maxilla, while the other had no axial undercuts on her few remaining maxillary teeth. Without an obturator, both suffered considerable air and fluid leaks, unintelligible speech, and swallowing problems. They too were successfully restored with obturators containing a heat‐cured, multi‐cup, silicone liner. The multi‐cup, silicone denture liner has offered an economic, noninvasive alternative for patients unable or unwilling to undergo surgical intervention to facilitate prosthesis retention.
Overwintering of annual bluegrass weevils, Listronotus maculicollis, in the golf course landscape
Authors: Diaz Maria Derval C. , Peck Daniel C. 
Published: October 2007

AbstractAnnual bluegrass weevil, Listronotus maculicollis (Dietz) (Coleoptera: Curculionidae), adults overwinter in protected areas but their life cycle is completed on highly maintained turfgrass. To better target control tactics on affected golf courses, we need to understand the relationship between overwintering and developmental habitats. Our objectives were to identify factors that influence overwintering site selection and to gather evidence of directional movement. Surveys of natural field populations were conducted in early spring over 2 years to test how abundance of overwintered adults depends on microhabitat (surface composition) and distance from the developmental habitat. The influence of microhabitat on overwintering preference and success was further tested in a multiple‐choice and no‐choice field experiment by relocating overwintering weevils into experimental arenas where four microhabitats were presented together or singly. The timing and direction of dispersal by walking adults was assessed using paired linear pitfall traps. Results showed that adults could overwinter up to 60 m from the fairway and 10 m into the woods. They were most abundant near the tree line; none were detected within 5 m of the fairway. Microhabitat had a significant effect on abundance in 1 year, being highest in mixed tree litter followed by moss, high‐cut grass, and pine litter. Under multiple‐choice conditions, high‐cut grass was preferred over low‐cut grass and leaf litter, followed by pine litter. Pitfall trap captures showed a peak of activity in the spring, and at one site this was directional toward the fairway. There was no directionality or increase in activity in the fall. Based on these results, a new conceptual model of flux between habitats is proposed based on orientation of flying adults to defined tree lines. Defining this behavior will strengthen our ability to target control tactics in space and time against this major turf pest.
Activation of Src‐family tyrosine kinases in hyperproliferative epidermal disorders
Authors: Ayli Elias E. , Li Weijie , Brown Tamu T. , Witkiewicz Agnieszka , Elenitsas Rosalie , Seykora John T. 
Published: October 2007

Background:  Src‐family tyrosine kinases (SFKs) are important regulators of keratinocyte growth and differentiation. In a broad range of cell types, persistent activation of SFKs correlates with increased cell proliferation. In this study, we determined if SFK activity is increased in cutaneous neoplasia and psoriasis, common hyperproliferative epidermal disorders.Methods:  Formalin‐fixed tissue sections of unremarkable epidermis, psoriasis, actinic keratoses (AKs), squamous cell carcinoma in situ (SCIS) and squamous cell carcinoma (SCC) were subjected to immunohistochemical staining for activated SFKs.Results:  All psoriasis specimens displayed significantly greater staining for activated SFKs than sections of unremarkable skin. In the psoriasis biopsies, the degree of epidermal hyperplasia was proportional to the level of activated SFK staining. All AKs, SCISs and SCCs exhibited more prominent staining than sections of unremarkable epidermis. No discernable difference in activated SFK staining was seen between AKs, SCIS and SCC specimens.Conclusions:  This study shows increased staining of activated SFKs in human biopsy specimens of psoriasis and cutaneous neoplasia. These data provide direct evidence for increased activation of SFKs in the pathogenesis of hyperproliferative epidermal disorders.
The fate of paternal mitochondria in marmoset pre‐implantation embryos
Authors: Luetjens C.M. , Wesselmann R. 
Published: October 2007

AbstractBackground  Sperm‐derived mitochondria are integrated into the oocyte at fertilization but seem to vanish during the early cleavage phase. The developmental potential of pre‐implantation embryos seems to be closely related to their ability to induce degeneration of these mitochondria, but the mechanisms underlying their loss of function are not yet understood. This study focuses on the fate of paternal mitochondria in pre‐implantation embryos.Methods  Stimulation, collection and in vitro culture of oocytes from Callithrix jacchus, allows the study of the destiny of paternal mitochondria by utilizing immunostaining of pre‐implantation embryos, fluorescence and laserscanning microscopy. Live pre‐implantation embryos were stained with a fluorescence indicator reflecting mitochondrial membrane potential.Results  Evidence indicating the loss of mitochondrial function was not found nor that apoptosis pathways were involved in the disappearance of paternally derived mitochondria.Conclusions  These findings may have implications for mitochondrially inherited diseases and could lead to new strategies for improving assisted reproduction.
Topical administration of simvastatin recovers alveolar bone loss in rats
Authors: Seto H. , Ohba H. , Tokunaga K. , Hama H. , Horibe M. , Nagata T. 
Published: October 2007

Background and Objective:  Simvastatin, a cholesterol‐lowering drug, has been reported to show anabolic effects on bone metabolism. We examined the effects of simvastatin in vitro using cultured rat calvaria cells and in vivo using periodontitis‐induced rats.Material and Methods:  Alkaline phosphatase activity and bone nodule formation were measured in cultured rat calvaria cells. Nylon ligature was placed around the maxillary molars of Fischer male rats for 20 d to induce alveolar bone resorption. After ligature removal, simvastatin was topically injected into the buccal gingivae for 70 d and then microcomputed tomography and histological examinations were performed.Results:  Simvastatin maintained high alkaline phosphatase activity and increased bone nodule formation in rat calvaria cells in a dose‐dependent manner, showing that simvastatin increased and maintained a high level of osteoblastic function. Microcomputed tomography images revealed that treatment with simvastatin recovered the ligature‐induced alveolar bone resorption, showing a 46% reversal of bone height. Histological examination clarified that low‐mineralized alveolar bone was formed in simvastatin‐treated rats.Conclusion:  These findings demonstrate that simvastatin has the potential to stimulate osteoblastic function and that topical administration of simvastatin may be effective for the recovery of alveolar bone loss in rats.