bluuebunny/crossref_metadata_2025_split huggingface dataset:
Similarity of Stress Distribution in Bone for Various Implant Surface Roughness Heights of Similar Form
Authors: Skalak Richard , Zhao Yihua 
Published: April 2007

ABSTRACT Background: Surface roughness effects on osseointegration can be considered from two viewpoints: purely mechanical effects Distresses attributable to roughness and cell and molecular response to surface roughness. Purpose: The goal of this study is to provide a theoretical basis to understand the effects of surface roughness size on the osseointegration of implants. The emphasis is primarily on the purely mechanical effects. Methods: Mathematical proofs of some similarity principles are provided. Results: The main result is that if the geometric form of the roughness or thread cross‐section is held constant, then the peak elastic stress depends on the form but not on the size of the roughness or thread height. Conclusion: The purely mechanical effects of surface roughness are well understood on a theoretical basis. The interpretation for clinical procedures, however, needs careful attention. Considering the present state of knowledge and clinical experience, no change in the roughness height of current practice is recommended.
Evaluation of Factors Influencing the Marginal Bone Stability around Implants in the Treatment of Partial Edentulism
Authors: Naert Ignace , Duyck Joke , Hosny Mahmoud , Jacobs Reinhilde , Quirynen Marc , van Steenberghe Daniel 
Published: April 2007

ABSTRACT Background: The original protocol or Branemark to achieve predictable osseointegration for oral implants has substantially been modified. One may question whether results are influenced by those modifications, especially for the longterm prognosis. Purpose: The goal of the present study was to investigate the impact of those parameters that deviate from the original protocol as defined by P‐I Branemark. Materials and Methods: In this study, 246 patients with 263 fixed partial prostheses supported by 668 Branemark implants were followed from 1 to 15 years (mean:6.3 yr). Radiographs were taken at the time of abutment connection, at 3 to 6 months, at 12 months, and then every 3 years. The bone level was rated mesially and distally from the implants on a total of 2588 radiographs. Results: A positive relation between abutment length and marginal bone level was found (p >.0001). The maxilla (p =.03), porcelain (p =.007), long abutments (p =.008), and regular‐sized diameter implants (p =.001) all exhibited more bone loss in the first 6 months. After 6 months, only long implants showed more bone loss (p =.03). Conclusions: Overall, the marginal bone level remained stable around Branemark implants, never surpassing 2.2 mm, even after 15 years. Although longer implants lost more bone over time, this has to be interpreted with respect to higher resorption rates in less resorbed jaws.
Nonresorbable versus Resorbable Sutures in Oral Implant Surgery: A Prospective Clinical Study
Authors: Ivanoff Carl‐Johan , Widmark Göran 
Published: April 2007

ABSTRACT Background: Regarding the Brånemark implant system, nonresorbable sutures have been advocated for reapproxima‐tion of the flaps. Fast‐absorbable sutures are frequently used in oral surgery, which is convenient for both the patient and the surgeon. It would be advantageous if fast‐absorbable sutures are suitable in implant surgery as well. Purpose: The purpose of this study was to compare irradiated polyglactin 910 (Vicryl Rapide, Ethicon GmbH, Norderstedt, Germany) suture with a nonresorbable polyfilament suture (Supramid, Schwarz, Resorba GmbH, Nürnberg, Germany) used in oral implant surgery. Materials and Methods: The study comprised 101 edentulous patients (52 females, 49 males) who were provided with 350 Brånemark implants. They were randomized to receive either Vicryl Rapide suture (n = 61) or 3‐0 Supramid suture (n = 40). The patients were evaluated after 10 days and at the time of abutment surgery. Any wound complications and implant losses were recorded. Results: The implant failure rate at abutment surgery was low (1.2%), and no difference was seen between the two suture groups. A higher incidence of complications (mainly wound dehiscence) was found in the absorbable suture group, especially when a continuous suture was used. Conclusions: The results of this study indicate that it is possible to use irradiated polyglactin 910 sutures in oral implant surgery without affecting the rate of early implant failure. However, it is recommended to add interrupted “security sutures” if a continuous suture technique is used in combination with fast‐absorption suture material.
In Search of Truth: The Role of Systematic Reviews and Meta‐Analyses for Assessing the Effectiveness of Rehabilitation with Oral Implants
Authors: Esposito Marco , Worthington Helen V. , Coulthard Paul 
Published: April 2007

Abstract: Background: It is difficult to determine the effectiveness or potential harm of dental therapies. Thus, any tools able to condense reliable scientific information would be of benefit. Purpose: To discuss methods for the assessment of the scientific literature and, in particular, of systematic reviews for evaluating the effectiveness of oral implant rehabilitation procedures. Materials and Methods: Various study designs and methods to identify scientific evidence are described, discussed, and ranked. Issues on how to critically appraise randomized controlled clinical trials (RCTs) and systematic reviews are presented. Results: Properly conducted RCTs and structured critical systematic reviews are the gold standard of clinical research for assessing whether a therapeutic intervention is effective. In the field of oral implantology, there is an urgent need to implement more RCTs and to summarize their results in systematic reviews. Conclusions: Searching of the truth requires training and critical skill. Dentists should be trained on how to integrate their clinical experience with evidence‐based research and on how to discriminate between clinically useful scientific information and less useful research.
Preliminary Report of Immediately Loaded Altiva Natural Tooth Replacement Dental Implants
Authors: Buchs Andre U. , Levine Laurence , Moy Peter 
Published: April 2007

Abstract: Background: Osseointegration may be described as a direct contact between living bone and an alloplastic implant. It is thought that a period of undisturbed healing is required to ensure osseointegration. The length of the healing period is dependent on a number of factors, such as implant material, surface configuration, site preparation technique, bone quality, healing capacity of the osteotomy, and implant design. Elimination of the healing period offers distinct advantages in terms of cost of therapy and convenience to patients. Recently, a new one‐piece implant design was proposed that provides improved stability of the implant to allow immediate support of an interim prosthesis. Purpose: This article presents the initial clinical experiences when the Altiva Natural Tooth Replacement one‐piece implant was used in a human clinical trial. Materials and Methods: This was a prospective multicenter study of the placement and immediate loading of the one‐piece implant. A total of 142 implants were placed in the jaws of 93 patients. Implants were placed consecutively and were followed at specified intervals in three private clinical practices. Clinical performance was recorded relative to implant survival and prosthesis support. Results: The implant survival rate was 93.7%, with similar responses in the maxilla (95.0%) and the mandible (92.7%). When implant failure occurred, it was observed as mobility without infection within 3 to 5 weeks of implant insertion. Conclusions: On the basis of this trial, there is promising evidence that this implant design can succeed at rates similar to other designs that require conventional healing times.
Osseotite Implant: 3‐Year Prospective Multicenter Evaluation
Authors: Davarpanah Mithridade , Martinez Henry , Celletti Renato , Alcoforado Gil , Tecucianu Jean‐François , Etienne Daniel 
Published: April 2007

Abstract: Purpose: This prospective multicenter study evaluates the cumulative success rate of the Osseotite® implant after 3 years of prosthetic loading. Materials and Methods: A total of 413 Osseotite® implants (Implant Innovations®) were placed in 142 patients (completely or partially edentulous) in five dental offices exclusively devoted to implants. The average age of the patients was 58.3 years. Of the 413 implants, 191 were placed in the maxilla and 222 in the mandible; 271 (65.6%) were posterior implants and 142 (34.4%) were anterior implants. Clinical and radiographic evaluations were made after completion of the prosthetic restoration, after 6 months of loading, at 1 year, and at 3 years. Results: A cumulative success rate of 95.3% was obtained after 3 years of prosthetic loading. The success rate was similar in both arches: 95.1% in the maxilla and 96.8% in the mandible. Early failures (before prosthetic loading) were greater (n = 12) than late failures (n = 2). After 3 years of prosthetic loading, the marginal bone level of 385 (93.2%) implants were evaluated radiographically. Bone level was at the first thread for 91.4% of the implants. A slightly increased loss was observed around 26 implants (6.7%). Including survival implants, the cumulative implant success rate after 3 years was 96%. A success rate of 98.4% was obtained with 187 short implants (8, 5 and 10 mm) reported in this multicenter evaluation. Conclusion: This multicenter evaluation demonstrates excellent predictability for Osseotite implants.
PhoU Is a Persistence Switch Involved in Persister Formation and Tolerance to Multiple Antibiotics and Stresses in
Escherichia coli
Authors: Li Yongfang , Zhang Ying 
Published: April 2007

ABSTRACT

When a bactericidal antibiotic is added to a growing bacterial culture, the great majority of the bacterial population is killed but a small number of metabolically quiescent bacteria called persisters survive antibiotic treatment. The mechanism of this bacterial persistence is poorly understood. In
Escherichia coli
, we identified a new persistence gene,
phoU
, whose inactivation leads to a generalized higher susceptibility than that of the parent strain to a diverse range of antibiotics, including ampicillin, norfloxacin, and gentamicin, and stresses, such as starvation, acid pH, heat, peroxide, weak acids, and energy inhibitors, especially in stationary phase. The PhoU mutant phenotype could be complemented by a functional
phoU
gene. Mutation in PhoU leads to a metabolically hyperactive status of the cell, as shown by an increased expression of energy production genes, flagella, and chemotaxis genes and a defect in persister formation. PhoU, whose expression is regulated by environmental changes like nutrient availability and age of culture, is a global negative regulator beyond its role in phosphate metabolism and facilitates persister formation by the suppression of many important cellular metabolic processes. A new model of persister formation based on PhoU as a persister switch is proposed. PhoU may be an ideal drug target for designing new drugs that kill persister bacteria for more effective control of bacterial infections.
Tigecycline Efflux as a Mechanism for Nonsusceptibility in
Acinetobacter baumannii
Authors: Peleg Anton Y. , Adams Jennifer , Paterson David L. 
Published: April 2007

ABSTRACT

Tigecycline has an extended spectrum of in vitro antimicrobial activities, including that against multidrug-resistant
Acinetobacter
. After identifying bloodstream isolates of
Acinetobacter
with reduced susceptibilities to tigecycline, we performed a study to assess tigecycline efflux mediated by the resistance-nodulation-division-type transporter AdeABC. After exposure of two tigecycline-nonsusceptible isolates to the efflux pump inhibitor phenyl-arginine-β-naphthylamide (PABN), a fourfold reduction in the tigecycline MIC was observed. Both tigecycline-susceptible and -nonsusceptible isolates were found to carry the gene coding for the transmembrane component of the AdeABC pump,
adeB
, and the two-component regulatory system comprising
adeS
and
adeR
. Previously unreported point mutations were identified in the regulatory system in tigecycline-nonsusceptible isolates. Real-time PCR identified 40-fold and 54-fold increases in
adeB
expression in the two tigecycline-nonsusceptible isolates compared to that in a tigecycline-susceptible isolate. In vitro exposure of a tigecycline-susceptible clinical strain to tigecycline caused a rapid rise in the MIC of tigecycline from 2 μg/ml to 24 μg/ml, which was reversible with PABN. A 25-fold increase in
adeB
expression was observed in a comparison between this tigecycline-susceptible isolate and its isogenic tigecycline-nonsusceptible mutant. These results indicate that an efflux-based mechanism plays a role in reduced tigecycline susceptibility in
Acinetobacter
.
Activity of T-1106 in a Hamster Model of Yellow Fever Virus Infection
Authors: Julander Justin G. , Furuta Yousuke , Shafer Kristiina , Sidwell Robert W. 
Published: April 2007

ABSTRACT
Yellow fever virus (YFV) causes 30,000 deaths worldwide, despite the availability of a vaccine. There are no approved antiviral therapies for the treatment of YFV disease in humans, and, therefore, these studies were designed to investigate the anti-YFV properties of T-1106, a substituted pyrazine, in a hamster model of YFV disease. Intraperitoneal (i.p.) treatment with 100 mg/kg of body weight/day of T-1106 starting 4 h prior to virus inoculation and continuing twice daily through 7 days post-virus inoculation (dpi) resulted in significantly improved survival, alanine aminotransferase levels in the serum, weight gain, and mean day to death. Virus titer in the liver at 4 dpi was significantly reduced in treated animals, as determined by both quantitative real-time PCR and infectious cell culture assay. No toxicity (weight loss or mortality) was observed at a dose of 100 mg/kg/day in sham-infected control animals. The observed minimal effective dose of T-1106 was 32 mg/kg/day administered either by oral or i.p. treatment. Therapeutic treatment was effective in significantly improving survival when T-1106 was administered beginning as late as 4 days after virus challenge with twice-daily treatment for 8 days at a dose of 100 mg/kg/day. With favorable safety, bioavailability, and postviral challenge treatment efficacy, T-1106 was effective in the treatment of disease in hamsters infected with YFV and should be further studied for potential use as a therapy for human YFV disease.
Host-Dependent Trigger of Caspases and Apoptosis by
Legionella pneumophila
Authors: Santic Marina , Asare Rexford , Doric Miljenko , Abu Kwaik Yousef 
Published: April 2007

ABSTRACT

The Dot/Icm system of
Legionella pneumophila
triggers activation of caspase-3 during early stages of infection of human macrophages, but apoptosis is delayed until late stages of infection. During early stages of infection of mouse macrophages, the organism triggers rapid caspase-1-mediated cytotoxicity, which is mediated by bacterial flagellin. However, it is not known whether caspase-1 is triggered by
L. pneumophila
in human macrophages or whether caspase-3 is activated in permissive or nonpermissive mouse macrophages. Using single-cell analyses, we show that the wild-type strain of
L. pneumophila
does not trigger caspase-1 activation throughout the intracellular infection of human monocyte-derived macrophages (hMDMs), even when the flagellated bacteria escape into the cytoplasm during late stages. Using single-cell analyses, we show that the Dot/Icm system of
L. pneumophila
triggers caspase-3 but not caspase-1 within permissive A/J mouse bone marrow-derived primary macrophages by 2 to 8 h, but apoptosis is delayed until late stages of infection. While
L. pneumophila
triggers a Dot/Icm-dependent activation of caspase-1 in nonpermissive BALB/c mouse-derived macrophages, caspase-3 is not activated at any stage of infection. We show that robust intrapulmonary replication of the wild-type strain of
L. pneumophila
in susceptible A/J mice is associated with late-stage Dot/Icm-dependent pulmonary apoptosis and alveolar inflammation. In the lungs of nonpermissive BALB/c mice,
L. pneumophila
does not replicate and does not trigger pulmonary apoptosis or alveolar inflammation. Thus, similar to hMDMs,
L. pneumophila
does not trigger caspase-1 but triggers caspase-3 activation during early and exponential replication in permissive A/J mouse-derived macrophages, and apoptosis is delayed until late stages of infection. The Dot/Icm type IV secretion system is essential for pulmonary apoptosis in the genetically susceptible A/J mice.
Identification of Midgut and Salivary Glands as Specific and Distinct Barriers to Efficient Tick-Borne Transmission ofAnaplasma marginale
Authors: Ueti Massaro W. , Reagan James O. , Knowles Donald P. , Scoles Glen A. , Shkap Varda , Palmer Guy H. 
Published: April 2007

ABSTRACTUnderstanding the determinants of efficient tick-borne microbial transmission is needed to better predict the emergence of highly transmissible pathogen strains and disease outbreaks. Although the basic developmental cycle ofAnaplasmaandEhrlichiaspp. within the tick has been delineated, there are marked differences in the ability of specific strains to be efficiently tick transmitted. Using the highly transmissible St. Maries strain ofAnaplasma marginaleinDermacentor andersonias a positive control and two unrelated nontransmissible strains, we identified distinct barriers to efficient transmission within the tick. The Mississippi strain was unable to establish infection at the level of the midgut epithelium despite successful ingestion of infected blood following acquisition feeding on a bacteremic animal host. This inability to colonize the midgut epithelium prevented subsequent development within the salivary glands and transmission. In contrast,A. marginalesubsp.centralecolonized the midgut and then the salivary glands, replicating to a titer indistinguishable from that of the highly transmissible St. Maries strain and at least 100 times greater than that previously associated with successful transmission. Nonetheless,A. marginalesubsp.centralewas not transmitted, even when a large number of infected ticks was used for transmission feeding. These results establish that there are at least two specific barriers to efficient tick-borne transmission, the midgut and salivary glands, and highlight the complexity of the pathogen-tick interaction.
Interleukin-8 Secretion in Response to Aferric Enterobactin Is Potentiated by Siderocalin
Authors: Nelson Aaron L. , Ratner Adam J. , Barasch Jonathan , Weiser Jeffrey N. 
Published: April 2007

ABSTRACT

Siderophores are low-molecular-weight iron chelators secreted by microbes to obtain iron under deprivation. We hypothesized that the catecholate siderophore enterobactin, produced by
Enterobacteriaceae
, serves as a proinflammatory signal for respiratory epithelial cells. Respiratory tract responses were explored, since at this site siderocalin, an enterobactin-binding mammalian gene product, is expressed inducibly at high levels and enterobactin-secreting respiratory flora is rare, suggesting selection against a dependence on enterobactin. Addition of aferric, but not iron-saturated, enterobactin elicits a dose-dependent increase in secretion of the proinflammatory chemokine interleukin-8 by human respiratory epithelial cells in culture. This response to purified enterobactin is potentiated by recombinant siderocalin at physiologically relevant concentrations. Conditioned media from genetically modified
Escherichia coli
strains expressing various levels of enterobactin induce an enterobactin-mediated proinflammatory response. Siderocalin has been shown to deliver enterobactin to other mammalian cell types, exogenously supplied siderocalin can be detected within epithelial cells, and siderocalin increases delivery of enterobactin to the intracellular compartment. Although many siderophores perturb labile cellular iron pools, only enterobactin elicits interleukin-8 secretion, suggesting that iron chelation is necessary but not sufficient. Thus, aferric enterobactin may be a proinflammatory signal for respiratory epithelial cells, permitting detection of microbial communities that have disturbed local iron homeostasis, and siderocalin expression by the host amplifies this signal. This may be a novel mechanism for the mucosa to respond to metabolic signals of expanding microbial communities.
Borrelia burgdorferiBinding of Host Complement Regulator Factor H Is Not Required for Efficient Mammalian Infection
Authors: Woodman Michael E. , Cooley Anne E. , Miller Jennifer C. , Lazarus John J. , Tucker Kathryn , Bykowski Tomasz , Botto Marina , Hellwage Jens , Wooten R. Mark , Stevenson Brian 
Published: April 2007

ABSTRACTThe causative agent of Lyme disease,Borrelia burgdorferi, is naturally resistant to its host's alternative pathway of complement-mediated killing. Several different borrelial outer surface proteins have been identified as being able to bind host factor H, a regulator of the alternative pathway, leading to a hypothesis that such binding is important for borrelial resistance to complement. To test this hypothesis, the development ofB. burgdorferiinfection was compared between factor H-deficient and wild-type mice. Factor B- and C3-deficient mice were also studied to determine the relative roles of the alternative and classical/lectin pathways inB. burgdorferisurvival during mammalian infection. While it was predicted thatB. burgdorferishould be impaired in its ability to infect factor H-deficient animals, quantitative analyses of bacterial loads indicated that those mice were infected at levels similar to those of wild-type and factor B- and C3-deficient mice. Ticks fed on infected factor H-deficient or wild-type mice all acquired similar numbers of bacteria. Indirect immunofluorescence analysis ofB. burgdorferiacquired by feeding ticks from the blood of infected mice indicated that none of the bacteria had detectable levels of factor H on their outer surfaces, even though such bacteria express high levels of surface proteins capable of binding factor H. These findings demonstrate that the acquisition of host factor H is not essential for mammalian infection byB. burgdorferiand indicate that additional mechanisms are employed by the Lyme disease spirochete to evade complement-mediated killing.