Stress as a Potential Modifier of the Impact of Lead Levels on Blood Pressure: The Normative Aging Study

BACKGROUND. Lead exposure and psychological stress have been independently associated with hypertension in various populations, and animal studies suggest that when they co-occur, their effects may be exacerbated. OBJECTIVES. We examined whether psychological stress modifies the impact of cumulative lead exposure (measured as bone lead levels) on hypertension and blood pressure in Boston-area community-exposed men participating in the Normative Aging Study. METHODS. We evaluated the modifying effect of stress on lead exposure on baseline hypertension status (513 participants) and on blood pressure in those without hypertension (237 participants), cross-sectionally. In baseline nonhypertensives, we examined the same risk factors in relation to prospective risk of developing hypertension. RESULTS. Cross-sectional analysis revealed a positive interaction between stress and tibia lead on systolic blood pressure, after adjusting for age, body mass index, family history of high blood pressure, education, smoking, alcohol consumption, physical activity, and nutritional factors. In prospective multivariate analyses, high stress also modified the effect of tibia lead and patella lead on the risk of developing hypertension. Those reporting high stress had 2.66 [95% confidence interval (CI), 1.43-4.95] times the risk of developing hypertension per standard deviation increase in tibia lead and had 2.64 (95% CI, 1.42-4.92) times the risk per standard deviation increase in patella lead. CONCLUSION. To our knowledge, these are the first analyses to look at interactive effects of stress and lead on hypertension in humans. These results suggest that the effect of lead on hypertension is most pronounced among highly stressed individuals, independent of demographic and behavioral risk factors.National Institutes of Health (R01-ES05257, P20-MD000501, P42-ES05947, GCRC M01-RR02635, ES03918-02); United States Department of Veterans Affair

Bacterial Sacroiliitis Probably Induced by Lumbar Epidural Analgesia

Background: Properly administered, lumbar epidural analgesia provides adequate pain relief during labor and delivery, and is considered to be a safe procedure with limited complications. The prevalence of infection after lumbar epidural analgesia is negligible. Introduction: Infection of the sacroiliac joint, although very close to the pucture area, has never been reported as a procedure complication. Case: In this report, we describe a patient who experienced bacterial sacroiliitis a few days after lumbar epidural analgesia for labor. No portal of entry was identified, and we evoked a new potential risk factor that has never been proposed before, namely lumbar epidural analgesia. Conclusion: Sacroiliitis must be considered as a rare but serious complication of lumbar epidural analgesia

Ototoksične tvari na radnom mjestu: kratak uvid u stanje

Ototoxic chemicals can impair the sense of hearing and balance. Lately, efforts have been intensifi ed to compile evidence-based lists of workplace agents with ototoxic properties. This article gives a rough overview of the latest relevant publications, which confirm that toluene, styrene, and lead should receive particular attention as ototoxic substances at the workplace. Moreover, there is sufficient evidence that occupational exposure to trichloroethylene, mercury, carbon monoxide, and carbon disulfide can affect the ear. Based on the existing information, industrial hygienists should make sure that occupational health professionals and the workforce are made aware of the risks posed by ototoxic substances; support their replacement or new technical measures to reduce exposure; make these substances a part of regular screening, develop tools that can early diagnose chemically induced hearing impairment, and investigate further into the ototoxic properties of these substances. Further research should focus on quantifying the combined effects of ototoxic substances and noise.Ototoksične kemikalije mogu narušiti osjetilo sluha i ravnotežu. Nedavno su uloženi dodatni napori u izradu znanstveno utemeljenih popisa tvari koje su prisutne na radnom mjestu, a koje imaju ototoksična svojstva. Ovaj rad daje kratak uvid u najnovije publikacije objavljene na ovu temu. Usporedba navedenih publikacija potvrđuje da bi toluen, stiren i olovo trebalo razmatrati kao izrazito bitne ototoksične tvari koje postoje na radnom mjestu. Nadalje, postoje dovoljni dokazi koji potvrđuju da ototoksične tvari poput trikloretilena, žive, ugljikova monoksida i disulfida u radnom okruženju mogu oštetiti sluh. Temeljem postojećih informacija stručnjaci u području higijene rada trebali bi upozoravati stručnjake u području medicine rada i same radnike na rizike koje ototoksične tvari predstavljaju; poticati ih na zamjenu takvih tvari ili uvođenje novih mjera za smanjenje izlaganja; uključiti ototoksične tvari u redoviti program praćenja i osmisliti mjere za rano otkrivanje oštećenja sluha zbog izloženosti kemijskim tvarima; dodatno istražiti ototoksična svojstva ovih tvari. Buduća istraživanja trebala bi se usredotočiti na izračun ukupnih učinaka ototoksičnih tvari i buke

ACTA OTORHINOLARYNGOLOGICA ITALICA

Il presente studio retrospettivo a singolo cieco si pone come obbiettivo quello di valutare in che percentuale di casi di pazienti che si presentano con sintomatologia compatibile con neurite vestibolare acuta, con e senza perdita oggettiva della funzione vestibulare (VFL), sia presente un conflitto neurovascolare fra il nervo vestibolococleare e la arteria cerebellare anteroinferiore (AICA). 58 pazienti con sintomatologia suggestiva per neurite vestibolare acuta, valutati con RMN presso un centro di terzo livello, sono stati confrontati con 61 pazienti asintomatici. I radiologi hanno dato valutato la presenza di conflitto neurovascolare, in assenza di dati clinici, conferendo ai rilievi oggettivi una valutazione in una scala da 0 a 3 a seconda che il contatto fosse: nesuno; inferiore a 2 mm; superiore ai 2 mm; presenza di vacular loop. I reperti neurootologici sono stati quindi raccolti alloscuro del risultato dellimaging. La funzione vestibolare è stata testata con prova calorica bitermica. Alla prova calorica 26 casi (45%) hanno mostrato segni oggettivi di deficit vestibolare (Gruppo A), 32 casi (55%) non hanno invece mostrato alcun deficit labirintico (Gruppo B). Il gruppo A ha incluso 13 casi (50%) con evidenza di conflitto neurovascolare (NVC), il gruppo B ha incluso 26 casi con NVC (82%) (p = 0.012) mentre i controlli hanno incluso 16 casi con NVC (26%). La differenza fra i tre gruppi ha mostrato significatività statistica (p 0.05). I nostri dati indicano che la presenza di conflitti neurovascolari a livello dellangolo pontocerebellare è superiore in quei pazienti che in presenza di una sintomatologia compatibile con neurite vestibolare acuta abbiano una funzionalità simmetrica alla prova calorica

Potassium Dependent Regulation of Astrocyte Water Permeability Is Mediated by cAMP Signaling

Astrocytes express potassium and water channels to support dynamic regulation of potassium homeostasis. Potassium kinetics can be modulated by aquaporin-4 (AQP4), the essential water channel for astrocyte water permeability regulation. We investigated whether extracellular potassium ([K+]o) can regulate astrocyte water permeability and the mechanisms of such an effect. Studies were performed on rat primary astrocytes and a rat astrocyte cell line transfected with AQP4. We found that 10mM [K+]o caused an immediate, more than 40%, increase in astrocyte water permeability which was sustained in 5min. The water channel AQP4 was a target for this regulation. Potassium induced a significant increase in intracellular cAMP as measured with a FRET based method and with enzyme immunoassay. We found that protein kinase A (PKA) could phosphorylate AQP4 in vitro. Further elevation of [K+]o to 35mM induced a global intracellular calcium response and a transient water permeability increase that was abolished in 5min. When inwardly rectifying potassium (Kir)-channels were blocked, 10mM [K+]o also induced a calcium increase and the water permeability increase no longer persisted. In conclusion, we find that elevation of extracellular potassium regulates AQP4 and astrocyte water permeability via intracellular signaling involving cAMP. A prolonged increase of astrocyte water permeability is Kir-channel dependent and this response can be impeded by intracellular calcium signaling. Our results support the concept of coupling between AQP4 and potassium handling in astrocytes

An improved method for constructing and selectively silanizing double-barreled, neutral liquid-carrier, ion-selective microelectrodes

We describe an improved, efficient and reliable method for the vapour-phase silanization of multi-barreled, ion-selective microelectrodes of which the silanized barrel(s) are to be filled with neutral liquid ion-exchanger (LIX). The technique employs a metal manifold to exclusively and simultaneously deliver dimethyldichlorosilane to only the ion-selective barrels of several multi-barreled microelectrodes. Compared to previously published methods the technique requires fewer procedural steps, less handling of individual microelectrodes, improved reproducibility of silanization of the selected microelectrode barrels and employs standard borosilicate tubing rather than the less-conventional theta-type glass. The electrodes remain stable for up to 3 weeks after the silanization procedure. The efficacy of a double-barreled electrode containing a proton ionophore in the ion-selective barrel is demonstrated in situ in the leaf apoplasm of pea (Pisum) and sunflower (Helianthus). Individual leaves were penetrated to depth of ~150 μm through the abaxial surface. Microelectrode readings remained stable after multiple impalements without the need for a stabilizing PVC matrix

Radiolucent lines in low-contact-stress mobile-bearing total knee arthroplasty: a blinded and matched case control study

<p>Abstract</p> <p>Background</p> <p>Low-contact-stress (LCS) mobile-bearing total knee arthroplasty (TKA) (Johnson & Johnson, New Brunswick, NJ; previously: DePuy, Warsawa, USA) provides excellent functional results and wear rates in long-term follow-up analyses. Radiological analysis shows radiolucent lines (RLL) appearing immediately or two years after primary implantation, indicative of poor seat. Investigations proved RLL to be more frequent in uncemented TKA, resulting in a consensus to cement the tibial plateau, but their association with clinical findings and patients discomfort and knee pain is still unknown.</p> <p>Methods</p> <p>553 patients with 566 low-contact-stress (LCS) total knee prostheses were screened for continuous moderate knee pain. We compared tibial stress shielding classified by Ewald in patients suffering from pain with a matched, pain-free control group on blinded X-rays. We hypothesized a positive correlation between pain and radiolucency and higher frequency of such radiolucent lines in the most medial and most lateral zones of the tibial plateau.</p> <p>Results</p> <p>Twenty-eight patients suffered from knee pain in total. Radiolucencies were detected in 27 of these cases and in six out of 28 matched controls without knee pain. We could demonstrate a significant correlation of knee pain and radiolucencies, which appeared significantly more frequently in the outermost zones of the tibial plateau.</p> <p>Conclusion</p> <p>Our findings suggest that radiolucent lines, representing poor implant seat, about the tibial plateau are associated with knee pain in LCS patients. Radiolucencies are observed more often in noncemented LCS, and cementing the tibial plateau might improve implant seat and reduce both radiolucent lines and associated knee pain.</p

The European project FLOMIX-R: Fluid mixing and flow distribution inthe reactor circuit - Final summary report

The project was aimed at describing the mixing phenomena relevant for both safety analysis, particularly in steam line break and boron dilution scenarios, and mixing phenomena of interest for economical operation and the structural integrity. Measurement data from a set of mixing experiments, gained by using advanced measurement techniques with enhanced resolution in time and space help to improve the basic understanding of turbulent mixing and to provide data for Computational Fluid Dynamics (CFD) code validation. Slug mixing tests simulating the start-up of the first main circulation pump are performed with two 1:5 scaled facilities: The Rossendorf coolant mixing model ROCOM and the VATTENFALL test facility, modelling a German Konvoi type and a Westinghouse type three-loop PWR, respectively. Additional data on slug mixing in a VVER-1000 type reactor gained at a 1:5 scaled metal mock-up at EDO Gidropress are provided. Experimental results on mixing of fluids with density differences obtained at ROCOM and the FORTUM PTS test facility are made available. Concerning mixing phenomena of interest for operational issues and thermal fatigue, flow distribution data available from commissioning tests (Sizewell-B for PWRs, Loviisa and Paks for VVERs) are used together with the data from the ROCOM facility as a basis for the flow distribution studies. The test matrix on flow distribution and steady state mixing performed at ROCOM comprises experiments with various combinations of running pumps and various mass flow rates in the working loops. Computational fluid dynamics calculations are accomplished for selected experiments with two different CFD codes (CFX-5, FLUENT). Best practice guidelines (BPG) are applied in all CFD work when choosing computational grid, time step, turbulence models, modelling of internal geometry, boundary conditions, numerical schemes and convergence criteria. The BPG contain a set of systematic procedures for quantifying and reducing numerical errors. The knowledge of these numerical errors is a prerequisite for the proper judgement of model errors. The strategy of code validation based on the BPG and a matrix of CFD code validation calculations have been elaborated. Besides of the benchmark cases, additional experiments were calculated by new partners and observers, joining the project later. Based on the "best practice solutions", conclusions on the applicability of CFD for turbulent mixing problems in PWR were drawn and recommendations on CFD modelling were given. The high importance of proper grid generation was outlined. In general, second order discretization schemes should be used to minimise numerical diffusion. First order schemes can provide physically wrong results. With optimised "production meshes" reasonable results were obtained, but due to the complex geometry of the flow domains, no fully grid independent solutions were achieved. Therefore, with respect to turbulence models, no final conclusions can be given. However, first order turbulence models like K-e or SST K-w are suitable for momentum driven slug mixing. For buoyancy driven mixing (PTS scenarios), Reynolds stress models provide better results

Assessing the distribution of volatile organic compounds using land use regression in Sarnia, "Chemical Valley", Ontario, Canada

<p>Abstract</p> <p>Background</p> <p>Land use regression (LUR) modelling is proposed as a promising approach to meet some of the challenges of assessing the intra-urban spatial variability of ambient air pollutants in urban and industrial settings. However, most of the LUR models to date have focused on nitrogen oxides and particulate matter. This study aimed at developing LUR models to predict BTEX (benzene, toluene, ethylbenzene, m/p-xylene and o-xylene) concentrations in Sarnia, 'Chemical Valley', Ontario, and model the intra-urban variability of BTEX compounds in the city for a community health study.</p> <p>Method</p> <p>Using Organic Vapour Monitors, pollutants were monitored at 39 locations across the city of Sarnia for 2 weeks in October 2005. LUR models were developed to generate predictor variables that best estimate BTEX concentrations.</p> <p>Results</p> <p>Industrial area, dwelling counts, and highways adequately explained most of the variability of BTEX concentrations (<it>R</it>²: 0.78 – 0.81). Correlations between measured BTEX compounds were high (> 0.75). Although most of the predictor variables (e.g. land use) were similar in all the models, their individual contributions to the models were different.</p> <p>Conclusion</p> <p>Yielding potentially different health effects than nitrogen oxides and particulate matter, modelling other air pollutants is essential for a better understanding of the link between air pollution and health. The LUR models developed in these analyses will be used for estimating outdoor exposure to BTEX for a larger community health study aimed at examining the determinants of health in Sarnia.</p

Clinical improvement in a patient with monostotic melorheostosis after treatment with denosumab: a case report

Abstract Background A 20-year-old Danish woman with melorheostosis in her right femoral shaft and disabling pain in the affected area, whose symptoms did not in the long term respond to zoledronic acid, experienced continuous remission of pain after treatment with denosumab. To the best of our knowledge, this is the first case report on denosumab treatment for melorheostosis. Case presentation Radiologic findings and bone biopsy showed irregular cortical hyperostosis in the right femoral shaft with increased tracer uptake on Tc99-bone scan. The diagnosis of melorheostosis was made based on the radiological findings. There was a good initial response to zoledronic acid administration, but after relapse of pain, the second and third administrations had a poor effect. As a second line of treatment denosumab was administered at 8-week intervals, the frequency was based on our patient’s symptoms and on biochemical markers of bone turnover. Conclusion This is the first report indicating that denosumab has a place in the treatment of melorheostosis when the effect of bisphosphonate treatment is insufficient