Fluoridated elastomers: Effect on the microbiology of plaque

The objective of this study was to investigate the effect of fluoridated elastomeric ligatures on the microbiology of local dental plaque in vivo. This randomized, prospective, longitudinal, clinical trial had a split-mouth crossover design. The subjects were 30 patients at the beginning of their treatment with fixed orthodontic appliances in the orthodontic departments of the Liverpool and the Sheffield dental hospitals in the United Kingdom. The study consisted of 2 experimental periods of 6 weeks with a washout period between. Fluoridated elastomers were randomly allocated at the first visit to be placed around brackets on tooth numbers 12, 11, 33 or 22, 21, 43. Nonfluoridated elastomers were placed on the contralateral teeth. Standard nonantibacterial fluoridated toothpaste and mouthwash were supplied. After 6 weeks (visit 2), the elastomers were removed, placed in transport media, and plated on agar within 2 hours. Nonfluoridated elastomers were placed on all brackets for 1 visit to allow for a washout period. At visit 3, fluoridated elastomers were placed on the teeth contralateral to those that received them at visit 1. At visit 4, the procedures at visit 2 were repeated. Samples were collected on visits 2 and 4. A logistic regression was performed, with the presence or absence of streptococcal or anaerobic growth as the dependent variable. A mixed-effects analysis of variance was carried out with the percentage of streptococcal or anaerobic bacterial count as the dependent variable. The only significant independent variables were the subject variable (P = < .001) for the percentage of streptococcal and anaerobic bacterial count and the visit variable for the percentage of streptococcal count (P = < .001). The use of fluoridated or nonfluoridated elastomers was not significant for percentage of either streptococcal (P = .288) or anaerobic count (P = .230). Fluoridated elastomers are not effective at reducing local streptococcal or anaerobic bacterial growth after a clinically relevant time in the mouth

The identification of genes important to the growth of Staphylococcus aureus in in vitro models mimicking infection.

Staphylococcus aureus is a major pathogen, which causes a wide range of infections. Despite its obvious clinical importance, little is known about the mechanisms of pathogenesis. An in vitro model mimicking infection was developed in order to identify putative virulence determinants. The model involves the growth of S. aureus in serum under microaerobic conditions. All known virulence factors tested were shown not to be required for growth, or preferentially expressed, in serum. Tn917 transposon libraries of S. aureus were screened to identify genes preferentially expressed in serum, compared to a nutrient-rich growth medium. 73 clones were identified and the transposon insertion site was characterised for 23 of these clones. Analysis of sequence flanking the transposon insertion revealed the identity of the mutated loci. 10 out of 23 sequenced clones, contained transposons inserted within genes involved in the biosynthesis of the aspartate family of amino acids (lysine. threonine, methionine and isoleucine). These were: the two common pathway enzymes; aspartokinase (lysC) , and aspartate semi aldehyde dehydrogenase (asd) , along with; dihydrodipicolinate dehydrogenase (dapA), and cystathionine y-synthase (yjcf) , involved in the biosynthesis oflysine and methionine respectively. Analysis of methionine biosynthesis indicated that S. aureus possesses only a single pathway, which proceeds via cystathionine. Several genes encoding methionine biosynthetic enzymes were found clustered on the S. aureus chromosome. The genes lyse, asd and dapA were found to be encoded by the first three genes of an eight gene operon, which also contains three other genes involved in lysine biosynthesis. This operon named the dap operon, is the major lysine biosynthetic operon of S. aureus. lysC, asd and dapA were all found to be repressed at the transcriptional level primarily by lysine, although factors other than the availability of lysine may be responsible for the regulation of lysine biosynthetic gene expression in serum. lysC, asd and dapA were all found to be expressed in vivo, in a murine pyelonephritis model using both RT-PCR and TaqMan techniques. However, these genes were not found to be important in three murine pathogenicity models. Finally, in addition to the development of a model mimicking infection, and the identification of genes with a potentially important role in vivo, this thesis has enhanced our understanding of both methionine and lysine biosynthesis in S. aureus

The impact of non weight bearing: a prospective cohort study

Patients with lower limb injuries are commonly advised to non weight bear (NWB) on their injured limb as part of treatment. Occasionally, patients complain that offloading one limb, associated with the use of crutches or other mobility aids, may lead to pain on one of the other supporting limbs. This has led to compensation claims (1) but has never been the subject of formal research.A prospective cohort trial was undertaken to address this question. Patients were recruited from two Metropolitan Hospital Orthopaedic Fracture Clinics and Orthopaedic Wards. A survey was administered at two time points; the first at the point of definitive orthopaedic treatment and commencement of the NWB phase. The second after the NWB phase was completed. The surveys included a pain Visual Analogue Scale (VAS), Short Form (SF)12, a pain body chart and a health questionnaire.A total of 55 patients were enrolled in the study. Seven patients developed new joint pain after a period NWB. These patients scored significantly lower on the follow up SF12 when compared to those who did not develop new pain (p=0.045). Follow up phone calls at least 6 months following completion of the second survey revealed that all initial and new pain areas in these participants had resolved. The main limitation of this study was the limited numbers.This study supports the idea that crutches, prescribed in the short term to allow a limb to be NWB, achieve this aim with minimal impact. Their use may be associated with new other joint pain however it can be anticipated this will resolve after cessation of crutch use

Genetic Dissection of a Key Reproductive Barrier Between Nascent Species of House Mice

Reproductive isolation between species is often caused by deleterious interactions among loci in hybrids. Finding the genes involved in these incompatibilities provides insight into the mechanisms of speciation. With recently diverged subspecies, house mice provide a powerful system for understanding the genetics of reproductive isolation early in the speciation process. Although previous studies have yielded important clues about the genetics of hybrid male sterility in house mice, they have been restricted to F1 sterility or incompatibilities involving the X chromosome. To provide a more complete characterization of this key reproductive barrier, we conducted an F2 intercross between wild-derived inbred strains from two subspecies of house mice, Mus musculus musculus and Mus musculus domesticus. We identified a suite of autosomal and X-linked QTL that underlie measures of hybrid male sterility, including testis weight, sperm density, and sperm morphology. In many cases, the autosomal loci were unique to a specific sterility trait and exhibited an effect only when homozygous, underscoring the importance of examining reproductive barriers beyond the F1 generation. We also found novel two-locus incompatibilities between the M. m. musculus X chromosome and M. m. domesticus autosomal alleles. Our results reveal a complex genetic architecture for hybrid male sterility and suggest a prominent role for reproductive barriers in advanced generations in maintaining subspecies integrity in house mice

Current transfusion practice and need for new blood products to ensure blood supply for patients with major hemorrhage in Europe

Background: New blood products are considered for treatment of patients with major hemorrhage. The aim of this report is to describe the current transfusion practices in Europe for patients with major hemorrhage and explore the need for new or modified blood products to ensure prehospital and in-hospital blood supply. Study Design and Method: The European Blood Alliance (EBA) Working Group on Innovation and New Blood Products' subgroup on major hemorrhage performed a survey among the EBA member states. Results: The response rate was 58% (17 responses from 15 of the 26 EBA member states). Of these, sixteen (94%) provide massive transfusion packages (MTPs) with balanced ratio of red blood cells and plasma. Seven of the respondents included platelets from the start of treatment. Eleven (65%) provide prehospital blood products, mainly red cell concentrates or dried and/or thawed plasma with 5 days of extended storage. Two countries provide prehospital whole blood. Twelve respondents (71%) saw a need for implementation of new or modified blood components in their institution. The top three priorities were whole blood (12 of 12, 100%), dried plasma (8 of 12, 67%), and cold-stored platelets (7 of 12, 58%). Discussion: Current national guidelines for use of blood products in patients with major hemorrhage in Europe agree on the use of balanced transfusion, however the timing and source of platelets differ. Blood products for prehospital transfusion are available in several European countries. An interest in new or modified blood products for patients with major hemorrhage was observed, especially for whole blood.publishedVersio

The WiggleZ Dark Energy Survey: the transition to large-scale cosmic homogeneity

We have made the largest-volume measurement to date of the transition to large-scale homogeneity in the distribution of galaxies. We use the WiggleZ survey, a spectroscopic survey of over 200,000 blue galaxies in a cosmic volume of ~1 (Gpc/h)^3. A new method of defining the 'homogeneity scale' is presented, which is more robust than methods previously used in the literature, and which can be easily compared between different surveys. Due to the large cosmic depth of WiggleZ (up to z=1) we are able to make the first measurement of the transition to homogeneity over a range of cosmic epochs. The mean number of galaxies N(<r) in spheres of comoving radius r is proportional to r^3 within 1%, or equivalently the fractal dimension of the sample is within 1% of D_2=3, at radii larger than 71 \pm 8 Mpc/h at z~0.2, 70 \pm 5 Mpc/h at z~0.4, 81 \pm 5 Mpc/h at z~0.6, and 75 \pm 4 Mpc/h at z~0.8. We demonstrate the robustness of our results against selection function effects, using a LCDM N-body simulation and a suite of inhomogeneous fractal distributions. The results are in excellent agreement with both the LCDM N-body simulation and an analytical LCDM prediction. We can exclude a fractal distribution with fractal dimension below D_2=2.97 on scales from ~80 Mpc/h up to the largest scales probed by our measurement, ~300 Mpc/h, at 99.99% confidence.Comment: 21 pages, 16 figures, accepted for publication in MNRA

Relativistic theory of elastic deformable astronomical bodies: perturbation equations in rotating spherical coordinates and junction conditions

In this paper, the dynamical equations and junction conditions at the interface between adjacent layers of different elastic properties for an elastic deformable astronomical body in the first post-Newtonian approximation of Einstein theory of gravity are discussed in both rotating Cartesian coordinates and rotating spherical coordinates. The unperturbed rotating body (the ground state) is described as uniformly rotating, stationary and axisymmetric configuration in an asymptotically flat space-time manifold. Deviations from the equilibrium configuration are described by means of a displacement field. In terms of the formalism of relativistic celestial mechanics developed by Damour, Soffel and Xu, and the framework established by Carter and Quintana the post Newtonian equations of the displacement field and the symmetric trace-free shear tensor are obtained. Corresponding post-Newtonian junction conditions at interfaces also the outer surface boundary conditions are presented. The PN junction condition is an extension of Wahr's one which is a Newtonian junction conditions without rotating.Comment: Revtex4, 14 page

EVALUATION OF THE QUALITY OF DIFFERENT BRANDS OF ASCORBIC ACID IN FREETOWN, SIERRA LEONE

Objective: This study evaluates the registration status and the quality of nine brands of Vitamin C sold in Freetown, Sierra Leone, using official and non-official methods of analysis. Methods: The parameters taken into consideration during the study include non-official methods (friability and disintegration) and the official methods (identification test, uniformity of dosage unit, and assay by titrimetric and colorimetric tests). The different brands of vitamin C were selected and classified as registered and unregistered based on the data derived from the National Medicines Regulatory Authority. Results: One vitamin C product collected was unregistered at the National medicines regulatory authority (Pharmacy Board of Sierra Leone). All nine vitamin C products met the requirements for uniformity of dosage unit. The vitamin C products also conformed to the BP specification for friability and identification test (retention factor). The identification test showed that each brand contained vitamin C (ascorbic acid). The disintegration test was not applicable for chewable tablets. Three of the four non-chewable vitamin C products complied with the BP specification for disintegration, while one failed and did not meet the requirement. The assay results for ascorbic acid using titration and colourimetric method were comparable and appropriate for determining vitamin C. Out of a total of nine samples; seven met the requirement for BP specification (Passed) for assay. In contrast, one product did not meet the BP requirement (failed), and one sample had more vitamin C than the Pharmacopoeia limit. Conclusion: Periodic quality evaluation and routine checks for pharmaceutical products can ascertain the quality of products, their storage conditions and identify potential counterfeit medications

Cosmological test of the Yilmaz theory of gravity

We test the Yilmaz theory of gravitation by working out the corresponding Friedmann-type equations generated by assuming the Friedmann-Robertson-Walker cosmological metrics. In the case that space is flat the theory is consistent only with either a completely empty universe or a negative energy vacuum that decays to produce a constant density of matter. In both cases the total energy remains zero at all times, and in the latter case the acceleration of the expansion is always negative. To obtain a more flexible and potentially more realistic cosmology, the equation of state relating the pressure and energy density of the matter creation process must be different from the vacuum, as for example is the case in the steady-state models of Gold, Bondi, Hoyle and others. The theory does not support the cosmological principle for curved space K =/= 0 cosmological metrics

Emergent airway management outside of the operating room - a retrospective review of patient characteristics, complications and ICU stay.

BACKGROUND: Emergent airway management outside of the operating room is a high-risk procedure. Limited data exists about the indication and physiologic state of the patient at the time of intubation, the location in which it occurs, or patient outcomes afterward. METHODS: We retrospectively collected data on all emergent airway management interventions performed outside of the operating room over a 6-month period. Documentation included intubation performance, and intubation related complications and mortality. Additional information including demographics, ASA-classification, comorbidities, hospital-stay, ICU-stay, and 30-day in-hospital mortality was obtained. RESULTS: 336 intubations were performed in 275 patients during the six-month period. The majority of intubations (n = 196, 58%) occurred in an ICU setting, and the rest 140 (42%) occurred on a normal floor or in a remote location. The mean admission ASA status was 3.6 ± 0.5, age 60 ± 16 years, and BMI 30 ± 9 kg/m2. Chest X-rays performed immediately after intubation showed main stem intubation in 3.3% (n = 9). Two immediate (within 20 min after intubation) intubation related cardiac arrest/mortality events were identified. The 30-day in-hospital mortality was 31.6% (n = 87), the overall in-hospital mortality was 37.1% (n = 102), the mean hospital stay was 22 ± 20 days, and the mean ICU-stay was 14 days (13.9 ± 0.9, CI 12.1-15.8) with a 7.3% ICU-readmission rate. CONCLUSION: Patients requiring emergent airway management are a high-risk patient population with multiple comorbidities and high ASA scores on admission. Only a small number of intubation-related complications were reported but ICU length of stay was high