bluuebunny/crossref_metadata_2025_split huggingface dataset:
Epigenetic acquisition of inducibility of type III cytotoxicity in P. aeruginosa
Authors: Filopon Didier , Mérieau Annabelle , Bernot Gilles , Comet Jean-Paul , LeBerre Rozenne , Guery Benoit , Polack Benoit , Guespin-Michel Janine 
Published: May 2006

Abstract

Background

Pseudomonas aeruginosa, an opportunistic pathogen, is often encountered in chronic lung diseases such as cystic fibrosis or chronic obstructive pneumonia, as well as acute settings like mechanical ventilation acquired pneumonia or neutropenic patients. It is a major cause of mortality and morbidity in these diseases. In lungs, P. aeruginosa settles in a biofilm mode of growth with the secretion of exopolysaccharides in which it is encapsulated, enhancing its antibiotic resistance and contributing to the respiratory deficiency of patients. However, bacteria must first multiply to a high density and display a cytotoxic phenotype to avoid the host's defences. A virulence determinant implicated in this step of infection is the type III secretion system (TTSS), allowing toxin injection directly into host cells. At the beginning of the infection, most strains isolated from patients' lungs possess an inducible TTSS allowing toxins injection or secretion upon in vivo or in vitro activation signals. As the infection persists most of the bacteria permanently loose this capacity, although no mutations have been evidenced. We name "non inducible" this phenotype. As suggested by the presence of a positive feedback circuit in the regulatory network controlling TTSS expression, it may be due to an epigenetic switch allowing heritable phenotypic modifications without genotype's mutations.

Results
Using the generalised logical method, we designed a minimal model of the TTSS regulatory network that could support the epigenetic hypothesis, and studied its dynamics which helped to define a discriminating experimental scenario sufficient to validate the epigenetic hypothesis. A mathematical framework based on formal methods from computer science allowed a rigorous validation and certification of parameters of this model leading to epigenetic behaviour. Then, we demonstrated that a non inducible strain of P. aeruginosa can stably acquire the capacity to be induced by calcium depletion for the TTSS after a short pulse of a regulatory protein. Finally, the increased cytotoxicity of a strain after this epigenetic switch was demonstrated in vivo in an acute pulmonary infection model.

Conclusion
These results may offer new perspectives for therapeutic strategies to prevent lethal infections by P. aeruginosa by reverting the epigenetic inducibility of type III cytotoxicity.
Should Patients with Apparently Sporadic Pheochromocytomas or Paragangliomas be Screened for Hereditary Syndromes?
Authors: Jiménez Camilo , Cote Gilbert , Arnold Andrew , Gagel Robert F. 
Published: May 2006

Abstract
Context: The recent identification of germline mutations of the mitochondrial complex II genes in variants of paraganglioma/pheochromocytoma syndrome has enlarged the number of known causative genes for hereditary pheochromocytoma. A question confronting clinicians is whether they should screen patients with apparently sporadic pheochromocytomas for unsuspected germline mutations of some or all of the seven genes known to cause hereditary paraganglioma or pheochromocytoma (NF1, VHL, RET, MEN1, SDHD, SDHC, and SDHB). A positive answer was suggested by a report that placed the estimate of hereditary disease in apparently sporadic pheochromocytoma as high as 24%.
Evidence Acquisition: We applied clinically useful criteria to a review of the literature, defining cases of apparently sporadic pheochromocytoma as those without a suspicious personal or family history, with a focal, unilateral pheochromocytoma, and presenting at age less than 50 yr.
Evidence Synthesis: We reduced the overall estimate of unsuspected hereditary pheochromocytoma patients with apparently sporadic pheochromocytoma to approximately 17%. Mutations in only three genes (VHL, SDHB, and SDHD) accounted for almost this entire minority, and unsuspected RET mutation was rare. Costs, coverage by insurance, the potential effect on insurability, and deficient information for populations outside of referral centers should be considered before recommending genetic testing in patients with apparently sporadic presentations of pheochromocytomas.
Conclusion: We recommend genetic testing for patients with an apparently sporadic pheochromocytoma under the age of 20 yr with family history or features suggestive of hereditary pheochromocytoma or for patients with sympathetic paragangliomas. For individuals who do not meet these criteria, genetic testing is optional.
Effect of Bauschinger-Modified Autofrettage Residual Stresses on Cannon Fatigue Life
Authors: Underwood JH , Parker AP , Troiano E 
Published: May 2006

Abstract
Fatigue modeling of autofrettaged cannons is described, including design modifications for steel vessels with 1170 MPa strength. A similar Ni-Cr-Mo-V steel but with 1360 MPa strength is planned to reduce weight. A new design must include modeling of the hoop compressive residual stress at the inner diameter, that has significant control of both the yield pressure and fatigue life. Results shows good agreement between measured lives from full-size cannon tests and calculated Paris lives including a Bauschinger-reduced material strength. Paris life calculations show effects of three important pressure vessel variables: initial crack size, extent of autofrettage, and outer-to-inner radius ratio.
The Stop Signal Revised: Immature Cerebellar Granule Neurons in the External Germinal Layer Arrest Pontine Mossy Fiber Growth
Authors: Manzini M. Chiara , Ward M. Stanton , Zhang Qin , Lieberman Michael D. , Mason Carol A. 
Published: May 2006

During the formation of neuronal circuits, afferent axons often enter target regions before their target cells are mature and then make temporary contacts with nonspecific targets before forming synapses on specific target cells. The regulation of these different steps of afferent-target interactions is poorly understood.The cerebellum is a good model for addressing these aspects, because cerebellar development is well defined and identified neurons in the circuitry can be purified and combinedin vitro. Previous reports from our laboratory showed that cultured granule neurons specifically arrest the extension of their pontine mossy fiber afferents, leading us to propose that granule cells arrested growth of their afferents as a prelude to synaptogenesis. However, we knew little about the differentiation state of the cultured granule cells that mediate afferent arrest.In this study, we better define the purified granule cell fraction by marker expression and morphology, and demonstrate that only freshly plated granule cells in the precursor and premigratory state arrest mossy fiber outgrowth. Mature granule cells, in contrast, support extension, defasciculation, and synapse formation, asin vivo. In addition, axonal tracingin vivoduring the first postnatal week indicates that immature mossy fibers extend into the Purkinje cell layer but never into the external germinal layer (EGL), where precursors of granule cell targets reside. We found that the stop-growing signals are dependent on heparin-binding factors, and we propose that such signals in the EGL restrict the extension of mossy fiber afferents and prevent invasion of proliferative regions.
Teaching Public Health Through a Pedagogy of Collegiality
Authors: Chávez Vivian , Turalba Ruby-Asuncion N. , Malik Savita 
Published: May 2006

Curriculum development in masters of public health programs that effectively meets the complex challenges of the 21st century is an important part of public health education and requires purposeful thinking. Current approaches to training the public health work-force do not adequately prepare professionals to be culturally competent in addressing health disparities. Principles of community-based participatory research highlight the importance of building relationships of mutual accountability and emphasize collegial teaching. We present background and theoretical foundations for a pedagogy of collegiality and describe specific teaching methods, classroom activities, and key assignments organized around 4 essential features: principles of community organizing, building community and valuing diversity, engaging the senses, and writing across the curriculum.
Unauthorized Border Crossings and Migrant Deaths: Arizona, New Mexico, and El Paso, Texas, 2002–2003
Authors: Sapkota Sanjeeb , Kohl Harold W. , Gilchrist Julie , McAuliffe Jay , Parks Bruce , England Bob , Flood Tim , Sewell C. Mack , Perrotta Dennis , Escobedo Miguel , Stern Corrine E. , Zane David , Nolte Kurt B. 
Published: May 2006

Objectives. We examined the major causes of and risk factors for death among migrants who died while making unauthorized border crossings into the United States from Mexico. Methods. Decedents were included in the study if (1) their remains were found between January 1, 2002, and December 31, 2003, in any US county along the 650-mi (1040-km) section of the US–Mexican border from Yuma, Ariz, to El Paso, Tex; (2) their immigration status was unauthorized; and (3) they were believed to have died during transit from Mexico to the United States. Characteristics of the decedents and causes of and risk factors for their deaths were examined. Results. Among the 409 decedents meeting our inclusion criteria, environmental heat exposure (n=250; 61.1%) was the leading cause of death, followed by vehicle crashes (n=33; 8.1%) and drownings (n=24; 5.9%). Male decedents (n= 298; 72.8%) outnumbered female decedents (n = 105; 25.6%) nearly 3 to 1. More than half of the decedents were known to be Mexican nationals (n=235; 57.5%) and were aged 20 to 39 years (n=213; 52.0%); the nationality of 148 (36.2%) decedents was undetermined. Conclusions. Deaths among migrants making unauthorized crossings of the US–Mexican border are due to causes that are largely preventable. Prevention strategies should target young Mexican men, and focus on preventing them from conceiving plans to cross the border, discouraging them from using dangerous routes as crossing points, and providing search-and-rescue teams to locate lost or injured migrant crossers.
The ratio of circulating osteoprotegerin to RANKL in early rheumatoid arthritis predicts later joint destruction
Authors: Geusens P. P. , Landewé R. B. M. , Garnero P. , Chen D. , Dunstan C. R. , Lems W. F. , Stinissen P. , van der Heijde D. M. F. M. , van der Linden S. , Boers M. 
Published: May 2006

AbstractObjectiveRheumatoid arthritis (RA) is a chronic inflammatory disease that may result in debilitating joint deformities with destruction of bone and cartilage. Inflammation is still considered the pivotal inducer of both components of joint damage. Results of recent animal studies suggested a prominent contribution of osteoclastic bone resorption that could be dissociated from inflammation. RANKL and its natural decoy receptor, osteoprotegerin (OPG), play key roles in osteoclast activation. In a group of patients with early RA not treated with disease‐modifying drugs, we tested the hypothesis that osteoclast activation, reflected by the serum OPG:RANKL ratio at baseline, is negatively associated with progression of bone damage, independent of inflammation.MethodsOPG and RANKL levels, together with a parameter of inflammation (first‐year time‐averaged erythrocyte sedimentation rate [tESR]), were measured in 92 patients with newly diagnosed early active RA who were participants in a randomized study. The tESR and the OPG:RANKL ratio were evaluated for the ability to predict 5‐year radiographic progression of joint damage.ResultsThe first‐year tESR and the OPG:RANKL ratio, as measured at baseline, independently predicted 5‐year radiographic progression of joint damage (bothP≤ 0.001). Progression of radiographic damage was greatest in patients with a high tESR and a low OPG:RANKL ratio and was lowest in patients with a low tESR and a high OPG:RANKL ratio.ConclusionThis study in patients with early untreated RA is the first to confirm the findings in animal models of arthritis, that radiographic progression of the bone component of joint destruction is dependent on both inflammation (tESR) and osteoclast activation (the OPG:RANKL ratio).
Selective portal clamping to minimize hepatic ischaemia–reperfusion damage and avoid accelerated outgrowth of experimental colorectal liver metastases
Authors: van der Bilt J D W , Kranenburg O , Verheem A , van Hillegersberg R , Borel Rinkes I H M 
Published: May 2006

Abstract

Background
Temporary vascular clamping during local ablation for colorectal liver metastases increases destruction volumes. However, it also causes ischaemia–reperfusion (IR) injury to the liver parenchyma and accelerates the outgrowth of microscopic tumour deposits. The aim of this study was to investigate the effects of selective portal clamping on hepatocellular damage and tumour growth.

Methods
Mice carrying pre-established hepatic colorectal micrometastases underwent either simultaneous clamping of both the portal vein and the hepatic artery or selective clamping of the portal vein to the median and left liver lobes for 45 min. Sham-operated mice served as controls. Hepatic injury and tumour growth were assessed over time.

Results
Standard inflow occlusion resulted in a rise in liver enzymes, a local inflammatory response and hepatocellular necrosis. The outgrowth of pre-established micrometastases was accelerated three- to fourfold in clamped compared with non-clamped liver lobes (27·4 versus 7·8 per cent, P &lt; 0·010). Conversely, selective portal clamping induced minimal liver injury, tissue inflammation or hepatocellular necrosis, and completely stopped the accelerated outgrowth of micrometastases.

Conclusion
Selective portal clamping does not induce liver tissue damage or accelerate micrometastasis outgrowth and may therefore be the preferable clamping method during local ablative treatment of hepatic metastases.
Clinical outcome of high segmental gastrectomy for early gastric cancer in the upper third of the stomach
Authors: Shinohara T , Ohyama S , Muto T , Kato Y , Yanaga K , Yamaguchi T 
Published: May 2006

Abstract

Background
Reflux oesophagitis is commonly encountered in the surgical treatment of cancer of the upper third of the stomach. The aim of this study was to describe a novel surgical technique and evaluate the clinical outcome of high segmental gastrectomy for early-stage proximal gastric cancer.

Methods
Thirty consecutive patients with early gastric cancer located in the upper third of the stomach were included, of whom 12 underwent high segmental gastrectomy and 18 underwent proximal gastrectomy with jejunal interposition. The incidence of reflux oesophagitis and nutritional parameters were compared between the two groups at 1 year after operation.

Results
One patient had mild reflux symptoms and two had endoscopic evidence of oesophagitis 1 year after high segmental gastrectomy. Half of the patients who had proximal gastrectomy had reflux symptoms of varying severity and 14 had endoscopic evidence of oesophageal changes at 1 year after surgery. There were significant differences between groups in the incidence of reflux symptoms (P = 0·016) and endoscopically detected gastro-oesophagitis (P &lt; 0·001). There were no adverse events in either group, and the survival rate after high segmental gastrectomy appeared favourable.

Conclusion
Selected patients with early-stage proximal gastric cancer benefit from high segmental gastrectomy in terms of reduced reflex oesophagitis, without jeopardizing curability.
Increased diagnostic yield of small bowel tumors with capsule endoscopy
Authors: Cobrin Gena M. , Pittman Robert H. , Lewis Blair S. 
Published: May 2006

AbstractBACKGROUNDIt is believed that cancers of the small intestine represent <2% of all malignant tumors of the gastrointestinal tract, although the accuracy of this estimate is unknown, because the current methodologies for examining the small bowel have proved inadequate. Capsule endoscopy allows a more detailed inspection of the small intestine and may improve the ability to diagnose small bowel tumors. The objective of this study was to evaluate the effectiveness of capsule endoscopy in diagnosing small bowel tumors and to help establish the true incidence of tumors in obscure gastrointestinal bleeding.METHODSA retrospective analysis of the charts of 562 patients who underwent capsule endoscopy from August 2001 to November 2003 for a variety of indications was performed. The indication for the procedure was bleeding (alone or in addition to another indication, such as abnormal imaging) in 443 patients.RESULTSA diagnosis was made by capsule endoscopy in 277 patients (49.3%). Of 562 patients who were included in the study, 50 patients (8.9%) were diagnosed with small bowel tumors. The types of tumor diagnosed by capsule endoscopy included 8 adenocarcinomas (1.4%), 10 carcinoids (1.8%), 4 gastrointestinal stromal tumors (0.7%), 5 lymphomas (0.9%), 3 inflammatory polyps, 1 lymphangioma, 1 lymphangioectasia,1 hemangioma, 1 hamartoma, and 1 tubular adenoma. Of the tumors diagnosed, 48% were malignant. It was observed that 9 of 67 patients (13%) younger than age 50 years who underwent capsule endoscopy for obscure bleeding had small bowel tumors. The pathology results were not available for 10 patients.CONCLUSIONSCapsule endoscopy diagnosed small bowel tumors in 8.9% of patients who underwent the procedure for a variety of reasons, establishing it as an effective diagnostic modality. This incidence of small bowel tumors suggests an important role for capsule endoscopy in the algorithm for the diagnostic work‐up of patients with suspected small bowel lesions. Capsule endoscopy may lead to earlier detection and treatment of small bowel tumors and an improved prognosis for patients with these neoplasms. Cancer 2006. © 2006 American Cancer Society.
Distinct subpopulations of cyclic guanosine monophosphate (cGMP) and neuronal nitric oxide synthase (nNOS) containing sympathetic preganglionic neurons in spontaneously hypertensive and Wistar‐Kyoto rats
Authors: Powers‐Martin Kellysan , McKitrick Douglas J. , Arnolda Leonard F. , Phillips Jacqueline K. 
Published: May 2006

AbstractThe sympathetic preganglionic neurons (SPN) of the intermediolateral cell column (IML) play a critical role in the maintenance of vascular tone. We undertook a comparative neuroanatomical analysis of neuronal nitric oxide synthase (nNOS) expression in the SPN of the mature normotensive Wistar Kyoto (WKY) and spontaneously hypertensive rat (SHR). The anatomical relationship between nNOS and the NO signaling molecule cyclic guanosine monophosphate (cGMP) was also determined. All animals were male, age >6 months. Fluorogold (FG) retrograde labeling of SPN (detected with immunohistochemistry) was combined with NADPH‐diaphorase histochemistry for NOS in the thoracic spinal cord (T1–11, n = 5 WKY, 5 SHR). There was no difference in the total number of FG‐labeled SPN (WKY 6,542 ± 828, SHR 6,091 ± 820), but the proportion of FG‐labeled cells expressing NOS was significantly less in the SHR (WKY 64.4 ± 5.1 vs. SHR 55.6 ± 2.1,P< 0.05). Fluorescence immunohistochemistry for nNOS/cGMP (n = 4 WKY, 4 SHR) was also performed. Confocal microscopy revealed that all nNOS‐positive SPN contain cGMP and confirmed a strain‐specific anatomical arrangement of SPN cell clusters. A novel subpopulation of cGMP‐only cells were also identified. Double labeling for cGMP and choline acetyltransferase (n = 3 WKY, 3 SHR), confirmed these cells as SPN in both WKY and SHR. These results suggest that cGMP is a key signaling molecule in SPN, and that a reduced number of NOS neurons in the SHR may play a role in the increase in sympathetic tone associated with hypertension in these animals. J. Comp. Neurol. 497:566–574, 2006. © 2006 Wiley‐Liss, Inc.
Osteoblast‐like cell attachment to and calcification of novel phosphonate‐containing polymeric substrates
Authors: Gemeinhart Richard A. , Bare Christopher M. , Haasch Richard T. , Gemeinhart Ernest J. 
Published: May 2006

AbstractIn an attempt to interact natural bone and bone cells with biomaterials and to begin to develop modular tissue engineering scaffolds, substrates containing phosphonate groups were identified to mimic mineral–protein and natural polymer–protein interactions. In this study, we investigated poly(vinyl phosphonic acid) copolymer integration with existing materials as a graft‐copolymer surface modification. Phosphonate‐containing copolymer‐modified surfaces were created and shown to have varying phosphate content within different polymeric surfaces. As the phosphonate content in the monomer feed approached 30% vinyl phosphonic acid, increased osteoblast‐like cell adhesion (3‐ to 8‐fold increase in adhesion) and proliferation (2‐ to10‐fold increase in proliferation rate) was observed. Since surfaces modified with 30% vinyl phosphonic acid in the feed exhibited a maximal cell adhesion and proliferation (9.4 × 104 cells/cm2/day), it was hypothesized that this copolymer composition was optimal for protein–polymer interactions. Osteoblast‐like cells formed confluent layers and were able to differentiate on all surfaces that contained vinyl phosphonic acid. Most importantly, cells interacting with these surfaces were able to significantly mineralize the surface. These results suggest that phosphonate‐containing polymers can be used to integrate biomaterials with natural bone and could be used for tissue engineering applications. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Crystallochemistry, textural properties, and in vitro biocompatibility of different silicon‐doped calcium phosphates
Authors: Arcos D. , Sánchez‐Salcedo S. , Izquierdo‐Barba I. , Ruiz L. , González‐Calbet J. , Vallet‐Regí M. 
Published: May 2006

AbstractThree silicon‐doped calcium phosphates (Si‐CaPs) were synthesized by heating precipitated silicon‐doped apatite via different thermal treatments. Temperatures of 700°C, 900°C, and 1100°C led to an apatite‐glass biphasic material, nanocrystalline Si‐doped apatite (SiHA), and Si‐doped apatite‐α tricalcium phosphate biphasic material, respectively. Structure, microstructure, textural properties, and chemical differences were determined for the three bioceramics. Biocompatibility tests were carried out by seeding osteblast‐like cells onto the three substrates. Si‐CaP treated at 700°C and 900°C led to Ca decrease in the culture media, partially impeding the cell proliferation over them. However, the proliferation capability is restored when additional culture medium is added. Finally, cytotoxicity results indicated that cell damage is much lower in osteblast‐like cells seeded onto SiHA and SiHA‐α tricalcium phosphate samples than in plastic culture control. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006