Staphylococcus aureus in the oral cavity: a three-year retrospective analysis of clinical laboratory data

OBJECTIVE: A retrospective analysis of laboratory data to investigate the isolation of Staphylococcus aureus from the oral cavity and facial area in specimens submitted to a regional diagnostic oral microbiology laboratory. METHODS: A hand search of laboratory records for a three-year period (1998-2000) was performed for specimens submitted to the regional diagnostic oral microbiology laboratory based at Glasgow Dental Hospital and School. Data were collected from forms where S. aureus was isolated. These data included demographics, referral source, specimen type, methicillin susceptibility and clinical details. RESULTS: For the period 1998-2000, there were 5,005 specimens submitted to the laboratory. S. aureus was isolated from 1,017 specimens, of which 967 (95%) were sensitive to methicillin (MSSA) and 50 (5%) were resistant to methicillin (MRSA). The 1,017 specimens were provided from 615 patients. MRSA was isolated from 37 (6%) of patients. There was an increasing incidence of S. aureus with age, particularly in the greater than 70 years age group. The most common specimen from which MSSA was isolated was an oral rinse (38%) whilst for MRSA isolates this was a tongue swab (28%). The clinical condition most commonly reported for MSSA isolates was angular cheilitis (22%). Erythema, swelling, pain or burning of the oral mucosa was the clinical condition most commonly reported for MRSA isolates (16%). Patients from whom the MSSA isolates were recovered were most commonly (55%) seen in the oral medicine clinic at the dental hospital, whilst patients with MRSA were more commonly seen in primary care settings such as nursing homes, hospices and general dental practice (51%). CONCLUSION: In line with more recent surveys, this retrospective study suggests that S. aureus may be a more frequent isolate from the oral cavity than hitherto suspected. A small proportion of the S. aureus isolates were MRSA. There were insufficient data available to determine whether the S. aureus isolates were colonising or infecting the oral cavity. However, the role of S. aureus in several diseases of the oral mucosa merits further investigation

Black Holes in Quasi-topological Gravity

We construct a new gravitational action which includes cubic curvature interactions and which provides a useful toy model for the holographic study of a three parameter family of four- and higher-dimensional CFT's. We also investigate the black hole solutions of this new gravity theory. Further we examine the equations of motion of quasi-topological gravity. While the full equations in a general background are fourth-order in derivatives, we show that the linearized equations describing gravitons propagating in the AdS vacua match precisely the second-order equations of Einstein gravity.Comment: 33 pages, 4 figures; two references adde

You turn me cold: evidence for temperature contagion

Introduction During social interactions, our own physiological responses influence those of others. Synchronization of physiological (and behavioural) responses can facilitate emotional understanding and group coherence through inter-subjectivity. Here we investigate if observing cues indicating a change in another's body temperature results in a corresponding temperature change in the observer. Methods Thirty-six healthy participants (age; 22.9±3.1 yrs) each observed, then rated, eight purpose-made videos (3 min duration) that depicted actors with either their right or left hand in visibly warm (warm videos) or cold water (cold videos). Four control videos with the actors' hand in front of the water were also shown. Temperature of participant observers' right and left hands was concurrently measured using a thermistor within a Wheatstone bridge with a theoretical temperature sensitivity of <0.0001°C. Temperature data were analysed in a repeated measures ANOVA (temperature × actor's hand × observer's hand). Results Participants rated the videos showing hands immersed in cold water as being significantly cooler than hands immersed in warm water, F(1,34) = 256.67, p0.1). There was however no evidence of left-right mirroring of these temperature effects p>0.1). Sensitivity to temperature contagion was also predicted by inter-individual differences in self-report empathy. Conclusions We illustrate physiological contagion of temperature in healthy individuals, suggesting that empathetic understanding for primary low-level physiological challenges (as well as more complex emotions) are grounded in somatic simulation

Signaling of the human P2Y(1) receptor measured by a yeast growth assay with comparisons to assays of phospholipase C and calcium mobilization in 1321N1 human astrocytoma cells

The human P2Y(1) receptor was expressed in the yeast Saccharomyces cerevisiae strain MPY578q5, which is engineered to couple to mammalian G protein-coupled receptors (GPCRs) and requires agonist-induced activation for growth. A range of known P2Y(1) receptor agonists were examined with the yeast growth assay system, and the results were validated by comparing with potencies in the transfected 1321N1 astrocytoma cell line, in which calcium mobilization was measured with a FLIPR (fluorometric-imaging plate reader). The data were also compared with those from phospholipase C activation and radioligand binding with the use of a newly available radioligand [(3)H]MRS2279 (2-chloro-N(6)-methyl-(N)-methanocarba-2’-deoxyadenosine-3’,5’bisphosphate). In the yeast growth assay, the rank order of potency of 2-MeSADP (2-methylthioadenosine 5’-diphosphate), ADP (adenosine 5’-diphosphate), and ATP (adenosine 5’-triphosphate) is the same as those in other assay systems, i.e., 2-MeSADP>ADP>ATP. The P2Y(1)-selective antagonist MRS2179 (N(6)-methyl-2-deoxyadenosine-3’,5’-bisphosphate) was shown to act as an antagonist with similar potency in all systems. The results suggest that the yeast expression system is suitable for screening P2Y(1) receptor ligands, both agonists and antagonists. The yeast system should be useful for random mutagenesis of GPCRs to identify mutants with certain properties, such as selective potency enhancement for small synthetic molecules and constitutive activity

Lovelock theories, holography and the fate of the viscosity bound

We consider Lovelock theories of gravity in the context of AdS/CFT. We show that, for these theories, causality violation on a black hole background can occur well in the interior of the geometry, thus posing more stringent constraints than were previously found in the literature. Also, we find that instabilities of the geometry can appear for certain parameter values at any point in the geometry, as well in the bulk as close to the horizon. These new sources of causality violation and instability should be related to CFT features that do not depend on the UV behavior. They solve a puzzle found previously concerning unphysical negative values for the shear viscosity that are not ruled out solely by causality restrictions. We find that, contrary to previous expectations, causality violation is not always related to positivity of energy. Furthermore, we compute the bound for the shear viscosity to entropy density ratio of supersymmetric conformal field theories from d=4 till d=10 - i.e., up to quartic Lovelock theory -, and find that it behaves smoothly as a function of d. We propose an approximate formula that nicely fits these values and has a nice asymptotic behavior when d goes to infinity for any Lovelock gravity. We discuss in some detail the latter limit. We finally argue that it is possible to obtain increasingly lower values for the shear viscosity to entropy density ratio by the inclusion of more Lovelock terms.Comment: 42 pages, 17 figures, JHEP3.cls. v2: reference adde

Perturbative quantum gravity with the Immirzi parameter

We study perturbative quantum gravity in the first-order tetrad formalism. The lowest order action corresponds to Einstein-Cartan plus a parity-odd term, and is known in the literature as the Holst action. The coupling constant of the parity-odd term can be identified with the Immirzi parameter of loop quantum gravity. We compute the quantum effective action in the one-loop expansion. As in the metric second-order formulation, we find that in the case of pure gravity the theory is on-shell finite, and the running of Newton's constant and the Immirzi parameter is inessential. In the presence of fermions, the situation changes in two fundamental aspects. First, non-renormalizable logarithmic divergences appear, as usual. Second, the Immirzi parameter becomes a priori observable, and we find that it is renormalized by a four-fermion interaction generated by radiative corrections. We compute its beta function and discuss possible implications. The sign of the beta function depends on whether the Immirzi parameter is larger or smaller than one in absolute value, and the values plus or minus one are UV fixed-points (we work in Euclidean signature). Finally, we find that the Holst action is stable with respect to radiative corrections in the case of minimal coupling, up to higher order non-renormalizable interactions.Comment: v2 minor amendment

Fungal Melanins Differ in Planar Stacking Distances

Melanins are notoriously difficult to study because they are amorphous, insoluble and often associated with other biological materials. Consequently, there is a dearth of structural techniques to study this enigmatic pigment. Current models of melanin structure envision the stacking of planar structures. X ray diffraction has historically been used to deduce stacking parameters. In this study we used X ray diffraction to analyze melanins derived from Cryptococcus neoformans, Aspergillus niger, Wangiella dermatitides and Coprinus comatus. Analysis of melanin in melanized C. neoformans encapsulated cells was precluded by the fortuitous finding that the capsular polysaccharide had a diffraction spectrum that was similar to that of isolated melanin. The capsular polysaccharide spectrum was dominated by a broad non-Bragg feature consistent with origin from a repeating structural motif that may arise from inter-molecular interactions and/or possibly gel organization. Hence, we isolated melanin from each fungal species and compared diffraction parameters. The results show that the inferred stacking distances of fungal melanins differ from that reported for synthetic melanin and neuromelanin, occupying intermediate position between these other melanins. These results suggest that all melanins have a fundamental diffracting unit composed of planar graphitic assemblies that can differ in stacking distance. The stacking peak appears to be a distinguishing universal feature of melanins that may be of use in characterizing these enigmatic pigments

Influence of an alkalizing supplement on markers of endurance performance using a double-blind placebo-controlled design

<p>Abstract</p> <p>Background</p> <p>Previous research has shown that ingestion of substances that enhance the body's hydrogen ion buffering capacity during high intensity exercise can improve exercise performance. The present study aimed to determine whether the chronic ingestion of an alkalizing supplement, which purports to enhance both intracellular and extracellular buffering capacity, could impact cardiorespiratory and performance markers in trained Nordic skiers.</p> <p>Methods</p> <p>Twenty-four skiers (12 men, 12 women), matched for upper body power (UBP), were split into treatment and placebo groups. The treatment group ingested Alka-Myte^®-based alkalizing tablets (1 tablet/22.7 kg body mass/day) over seven successive days while the placebo group consumed placebo tablets (i.e., no Alka-Myte^®) at the same dosage. Prior to tablet ingestion (i.e., pre-testing), both groups completed a constant power UBP test, three successive 10-sec UBP tests, and then a 60-sec UBP test. Next, skiers completed the 7-day ingestion of their assigned tablets followed immediately by a repeat of the same UBP tests (i.e., post-testing). Neither the skiers nor the researchers were aware of which tablets were being consumed by either group until after all testing was complete. Dependent measures for analysis included heart rate (HR), oxygen consumption (VO₂), minute ventilation (V_E), blood lactate (LA), as well as 10-sec (W10, W) and 60-sec (W60, W) UBP. All data were evaluated using a two-factor multivariate repeated measures ANOVA with planned contrasts for post-hoc testing (alpha = 0.05).</p> <p>Results</p> <p>Post-testing cardiorespiratory (HR, VO₂, V_E) and LA measures for the treatment group tended to be significantly lower when measured for both constant power and UBP60 tests, while measures of both 10-sec (W10: 229 to 243 W) and 60-sec UBP (W60: 190 to 198 W) were significantly higher (<it>P </it>< 0.05). In contrast, there were no significant changes for the placebo group (P > 0.05).</p> <p>Conclusions</p> <p>Following the 7-day loading phase of Alka-Myte^®-based alkalizing tablets, trained Nordic skiers experienced significantly lower cardiorespiratory stress, lower blood lactate responses, and higher UBP measures. Thus, the use of this supplement appeared to impart an ergogenic benefit to the skiers that may be similar to the effects expected from consuming well-studied extracellular buffering agents such as sodium bicarbonate.</p

Measurement properties of the Dizziness Handicap Inventory by cross-sectional and longitudinal designs

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