1,705 research outputs found

    A Novel Tantalum-Containing Bioglass. Part I. Structure and Solubility

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    Bio glasses are employed for surgical augmentation in a range of hard tissue applications. Tantalum is a bioactive and biocompatible transition metal that has been used as an orthopedic medical device. It has a range of biological and physical properties that make its incorporation into ionic form into bioactive glass systems promising for various clinical applications. The work herein reports the characterization and properties of novel tantalum-containing glasses. A series of glasses based on the system 48SiO2-(36-X)ZnO-6CaO-8SrO-2P2O5-XTa2O5 with X varying from 0 mol% (TA0) to 0.5 mol% (TA2) were synthesized. The addition of small amounts of Ta2O5 did not cause crystallization of the glasses but increasing Ta2O5 content at the expense of ZnO was found to result in an increased number of bridging oxygens (BOs). This, along with the data recorded by differential thermal analysis (DTA) and magic angle spinning-nuclear magnetic resonance (MAS-NMR), confirms that Ta acts as a glass former in this series. Solubility experiments showed that minor changes in the glass structure caused by Ta incorporation (0.5 mol%) exhibited greater cumulative % weight loss, pH values and cumulative Zn2+ and Sr2+ ion concentration over a period of 30 days of maturation, when compared to Ta2O5-free glasses. The results presented in this article confirm that replacing ZnO with Ta2O5 in silicate glasses results in the formation of stronger bonds within the glass network without any adverse effects on the solubility of the glasses prepared from them

    A Novel Tantalum-Containing Bioglass. Part II. Development of a Bioadhesive for Sternal Fixation and Repair

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    With over a million median sternotomy surgeries performed worldwide every year, sternal wound complications have posed a serious risk to the affected patients. A rigid therapeutic sternal fixation device has therefore become a necessity. In this work, the incorporation of up to 0.5 mol% of tantalum pentoxide (Ta2O5), in exchange for zinc oxide (ZnO), into the SiO2-ZnO-CaO-SrO-P2O5 glass system is presented. The effect of Ta incorporation on the physical, chemical and biological properties of the glass polyalkenoate cements (GPCs) prepared from them have been presented in this manuscript. The data obtained have confirmed that Ta2O5 incorporation into the reference glass system results in increased working times, radiopacity, ion solubility, and long-term mechanical stability. The formulated glass systems have also shown clear antibacterial and antifungal activity against both Gram-negative (Escherichia coli) and Gram-positive prokaryotes (Staphylococcus aureus and Streptococcus epidermidis), as well as eukaryotes (Fusarium solani). Cytotoxicity testing showed that Ta incorporation results in no toxicity effect and may simulate osseo-integration when tested in animal models. These new metallic-containing biomaterial adhesives have been developed for sternal fixation and repair. As a permanent implant, the formulated adhesives can be used in conjunction with sternal cable ties to offer optimal fixation for patients and reduce post-operative complications such as bacterial infection and pain from micro-motion

    Diagnosis and management of subcutaneous implantable cardioverter‐defibrillator infections based on process mapping

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    Background: Infection is a well‐recognized complication of cardiovascular implantable electronic device (CIED) implantation, including the more recently available subcutaneous implantable cardioverter‐defibrillator (S‐ICD). Although the AHA/ACC/HRS guidelines include recommendations for S‐ICD use, currently there are no clinical trial data that address the diagnosis and management of S‐ICD infections. Therefore, an expert panel was convened to develop consensus on these topics. / Methods: A process mapping methodology was used to achieve a primary goal – the development of consensus on the diagnosis and management of S‐ICD infections. Two face‐to‐face meetings of panel experts were conducted to recommend useful information to clinicians in individual patient management of S‐ICD infections. / Results: Panel consensus of a stepwise approach in the diagnosis and management was developed to provide guidance in individual patient management. / Conclusion: Achieving expert panel consensus by process mapping methodology in S‐ICD infection diagnosis and management was attainable, and the results should be helpful in individual patient management

    Toward Fulfilling the Promise of Molecular Medicine in Fragile X

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    Fragile X syndrome (FXS) is the most common inherited form of mental retardation and a leading known cause of autism. It is caused by loss of expression of the fragile X mental retardation protein (FMRP), an RNA-binding protein that negatively regulates protein synthesis. In neurons, multiple lines of evidence suggest that protein synthesis at synapses is triggered by activation of group 1 metabotropic glutamate receptors (Gp1 mGluRs) and that many functional consequences of activating these receptors are altered in the absence of FMRP. These observations have led to the theory that exaggerated protein synthesis downstream of Gp1 mGluRs is a core pathogenic mechanism in FXS. This excess can be corrected by reducing signaling by Gp1 mGluRs, and numerous studies have shown that inhibition of mGluR5, in particular, can ameliorate multiple mutant phenotypes in animal models of FXS. Clinical trials based on this therapeutic strategy are currently under way. FXS is therefore poised to be the first neurobehavioral disorder in which corrective treatments have been developed from the bottom up: from gene identification to pathophysiology in animals to novel therapeutics in humans. The insights gained from FXS and other autism-related single-gene disorders may also assist in identifying molecular mechanisms and potential treatment approaches for idiopathic autism.Eunice Kennedy Shriver National Institute of Child Health and Human Development (U.S.)National Institute of Mental Health (U.S.)FRAXA Research Foundatio

    Mapping the disease-specific LupusQoL to the SF-6D

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    Purpose To derive a mapping algorithm to predict SF-6D utility scores from the non-preference-based LupusQoL and test the performance of the developed algorithm on a separate independent validation data set. Method LupusQoL and SF-6D data were collected from 320 patients with systemic lupus erythematosus (SLE) attending routine rheumatology outpatient appointments at seven centres in the UK. Ordinary least squares (OLS) regression was used to estimate models of increasing complexity in order to predict individuals’ SF-6D utility scores from their responses to the LupusQoL questionnaire. Model performance was judged on predictive ability through the size and pattern of prediction errors generated. The performance of the selected model was externally validated on an independent data set containing 113 female SLE patients who had again completed both the LupusQoL and SF-36 questionnaires. Results Four of the eight LupusQoL domains (physical health, pain, emotional health, and fatigue) were selected as dependent variables in the final model. Overall model fit was good, with R2 0.7219, MAE 0.0557, and RMSE 0.0706 when applied to the estimation data set, and R2 0.7431, MAE 0.0528, and RMSE 0.0663 when applied to the validation sample. Conclusion This study provides a method by which health state utility values can be estimated from patient responses to the non-preference-based LupusQoL, generalisable beyond the data set upon which it was estimated. Despite concerns over the use of OLS to develop mapping algorithms, we find this method to be suitable in this case due to the normality of the SF-6D data

    Recent acquisition of Helicobacter pylori by Baka Pygmies

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    Both anatomically modern humans and the gastric pathogen Helicobacter pylori originated in Africa, and both species have been associated for at least 100,000 years. Seven geographically distinct H. pylori populations exist, three of which are indigenous to Africa: hpAfrica1, hpAfrica2, and hpNEAfrica. The oldest and most divergent population, hpAfrica2, evolved within San hunter-gatherers, who represent one of the deepest branches of the human population tree. Anticipating the presence of ancient H. pylori lineages within all hunter-gatherer populations, we investigated the prevalence and population structure of H. pylori within Baka Pygmies in Cameroon. Gastric biopsies were obtained by esophagogastroduodenoscopy from 77 Baka from two geographically separated populations, and from 101 non-Baka individuals from neighboring agriculturalist populations, and subsequently cultured for H. pylori. Unexpectedly, Baka Pygmies showed a significantly lower H. pylori infection rate (20.8%) than non-Baka (80.2%). We generated multilocus haplotypes for each H. pylori isolate by DNA sequencing, but were not able to identify Baka-specific lineages, and most isolates in our sample were assigned to hpNEAfrica or hpAfrica1. The population hpNEAfrica, a marker for the expansion of the Nilo-Saharan language family, was divided into East African and Central West African subpopulations. Similarly, a new hpAfrica1 subpopulation, identified mainly among Cameroonians, supports eastern and western expansions of Bantu languages. An age-structured transmission model shows that the low H. pylori prevalence among Baka Pygmies is achievable within the timeframe of a few hundred years and suggests that demographic factors such as small population size and unusually low life expectancy can lead to the eradication of H. pylori from individual human populations. The Baka were thus either H. pylori-free or lost their ancient lineages during past demographic fluctuations. Using coalescent simulations and phylogenetic inference, we show that Baka almost certainly acquired their extant H. pylori through secondary contact with their agriculturalist neighbors

    Reproducibility of pulmonary magnetic resonance angiography in adults with muco-obstructive pulmonary disease

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    Background Recent studies support magnetic resonance angiography (MRA) as a diagnostic tool for pulmonary arterial disease. Purpose To determine MRA image quality and reproducibility, and the dependence of MRA image quality and reproducibility on disease severity in patients with chronic obstructive pulmonary disease (COPD) and cystic fibrosis (CF). Material and Methods Twenty patients with COPD (mean age 66.5 ± 8.9 years; FEV1% = 42.0 ± 13.3%) and 15 with CF (mean age 29.3 ± 9.3 years; FEV1% = 66.6 ± 15.8%) underwent morpho-functional chest magnetic resonance imaging (MRI) including time-resolved MRA twice one month apart (MRI1, MRI2), and COPD patients underwent non-contrast computed tomography (CT). Image quality was assessed visually using standardized subjective 5-point scales. Contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) were measured by regions of interest. Disease severity was determined by spirometry, a well-evaluated chest MRI score, and by computational CT emphysema index (EI) for COPD. Results Subjective image quality was diagnostic for all MRA at MRI1 and MRI2 (mean score = 4.7 ± 0.6). CNR and SNR were 4 43.8 ± 8.7 and 50.5 ± 8.7, respectively. Neither image quality score nor CNR or SNR correlated with FEV1% or chest MRI score for COPD and CF (r = 0.239–0.248). CNR and SNR did not change from MRI1 to MRI2 (P = 0.434–0.995). Further, insignificant differences in CNR and SNR between MRA at MRI1 and MRI2 did not correlate with FEV1% nor chest MRI score in COPD and CF (r = −0.238–0.183), nor with EI in COPD (r = 0.100–0.111). Conclusion MRA achieved diagnostic quality in COPD and CF patients and was highly reproducible irrespective of disease severity. This supports MRA as a robust alternative to CT in patients with underlying muco-obstructive lung disease

    Effectiveness of moving on: an Australian designed generic self-management program for people with a chronic illness

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    Background: This paper presents the evaluation of “Moving On”, a generic self-management program for people with a chronic illness developed by Arthritis NSW. The program aims to help participants identify their need for behavior change and acquire the knowledge and skills to implement changes that promote their health and quality of life. Method: A prospective pragmatic randomised controlled trial involving two group programs in community settings: the intervention program (Moving On) and a control program (light physical activity). Participants were recruited by primary health care providers across the north-west region of metropolitan Sydney, Australia between June 2009 and October 2010. Patient outcomes were self-reported via pre- and post-program surveys completed at the time of enrolment and sixteen weeks after program commencement. Primary outcomes were change in self-efficacy (Self-efficacy for Managing Chronic Disease 6-Item Scale), self-management knowledge and behaviour and perceived health status (Self-Rated Health Scale and the Health Distress Scale). Results: A total of 388 patient referrals were received, of whom 250 (64.4%) enrolled in the study. Three patients withdrew prior to allocation. 25 block randomisations were performed by a statistician external to the research team: 123 patients were allocated to the intervention program and 124 were allocated to the control program. 97 (78.9%) of the intervention participants commenced their program. The overall attrition rate of 40.5% included withdrawals from the study and both programs. 24.4% of participants withdrew from the intervention program but not the study and 22.6% withdrew from the control program but not the study. A total of 62 patients completed the intervention program and follow-up evaluation survey and 77 patients completed the control program and follow- up evaluation survey. At 16 weeks follow-up there was no significant difference between intervention and control groups in self-efficacy; however, there was an increase in self-efficacy from baseline to follow-up for the intervention participants (t=−1.948, p=0.028). There were no significant differences in self-rated health or health distress scores between groups at follow-up, with both groups reporting a significant decrease in health distress scores. There was no significant difference between or within groups in self-management knowledge and stage of change of behaviours at follow-up. Intervention group attenders had significantly higher physical activity (t=−4.053, p=0.000) and nutrition scores (t=2.315, p= 0.01) at follow-up; however, these did not remain significant after adjustment for covariates. At follow-up, significantly more participants in the control group (20.8%) indicated that they did not have a self-management plan compared to those in the intervention group (8.8%) (X2=4.671, p=0.031). There were no significant changes in other self-management knowledge areas and behaviours after adjusting for covariates at follow-up. Conclusions: The study produced mixed findings. Differences between groups as allocated were diluted by the high proportion of patients not completing the program. Further monitoring and evaluation are needed of the impact and cost effectiveness of the program. Trial registration: Australian New Zealand Clinical Trials Registry: ACTRN1260900029821

    Oxaliplatin-induced loss of phosphorylated heavy neurofilament subunit neuronal immunoreactivity in rat DRG tissue

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    <p>Abstract</p> <p>Background</p> <p>Oxaliplatin and related chemotherapeutic drugs cause painful chronic peripheral neuropathies in cancer patients. We investigated changes in neuronal size profiles and neurofilament immunoreactivity in L5 dorsal root ganglion (DRG) tissue of adult female Wistar rats after multiple-dose treatment with oxaliplatin, cisplatin, carboplatin or paclitaxel.</p> <p>Results</p> <p>After treatment with oxaliplatin, phosphorylated neurofilament heavy subunit (pNF-H) immunoreactivity was reduced in neuronal cell bodies, but unchanged in nerve fibres, of the L5 DRG. Morphometric analysis confirmed significant changes in the number (-75%; <it>P </it>< 0.0002) and size (-45%; <it>P </it>< 0.0001) of pNF-H-immunoreactive neurons after oxaliplatin treatment. pNF-H-immunoreactive neurons had overlapping size profiles and co-localisation with neurons displaying cell body immunoreactivity for parvalbumin, non-phospho-specific neurofilament medium subunit (NF-M) and non-phospho-specific neurofilament heavy subunit (NF-H), in control DRG. However, there were no significant changes in the numbers of neurons with immunoreactivity for parvalbumin (4.6%, <it>P </it>= 0.82), NF-M (-1%, <it>P </it>= 0.96) or NF-H (0%; <it>P </it>= 0.93) after oxaliplatin treatment, although the sizes of parvalbumin (-29%, <it>P </it>= 0.047), NF-M (-11%, <it>P </it>= 0.038) and NF-H (-28%; <it>P </it>= 0.0033) immunoreactive neurons were reduced. In an independent comparison of different chemotherapeutic agents, the number of pNF-H-immunoreactive neurons was significantly altered by oxaliplatin (-77.2%; <it>P </it>< 0.0001) and cisplatin (-35.2%; <it>P </it>= 0.03) but not by carboplatin or paclitaxel, and their mean cell body area was significantly changed by oxaliplatin (-31.1%; <it>P </it>= 0.008) but not by cisplatin, carboplatin or paclitaxel.</p> <p>Conclusion</p> <p>This study has demonstrated a specific pattern of loss of pNF-H immunoreactivity in rat DRG tissue that corresponds with the relative neurotoxicity of oxaliplatin, cisplatin and carboplatin. Loss of pNF-H may be mechanistically linked to oxaliplatin-induced neuronal atrophy, and serves as a readily measureable endpoint of its neurotoxicity in the rat model.</p

    Dental Microwear and Diet of the Plio-Pleistocene Hominin Paranthropus boisei

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    The Plio-Pleistocene hominin Paranthropus boisei had enormous, flat, thickly enameled cheek teeth, a robust cranium and mandible, and inferred massive, powerful chewing muscles. This specialized morphology, which earned P. boisei the nickname “Nutcracker Man”, suggests that this hominin could have consumed very mechanically challenging foods. It has been recently argued, however, that specialized hominin morphology may indicate adaptations for the consumption of occasional fallback foods rather than preferred resources. Dental microwear offers a potential means by which to test this hypothesis in that it reflects actual use rather than genetic adaptation. High microwear surface texture complexity and anisotropy in extant primates can be associated with the consumption of exceptionally hard and tough foods respectively. Here we present the first quantitative analysis of dental microwear for P. boisei. Seven specimens examined preserved unobscured antemortem molar microwear. These all show relatively low complexity and anisotropy values. This suggests that none of the individuals consumed especially hard or tough foods in the days before they died. The apparent discrepancy between microwear and functional anatomy is consistent with the idea that P. boisei presents a hominin example of Liem's Paradox, wherein a highly derived morphology need not reflect a specialized diet
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