Objective
To assess survival and incidence of organ‐based complications in a large single‐center cohort of unselected systemic sclerosis (SSc) patients, and to explore predictors of survival and ...clinically significant pulmonary fibrosis (PF) and pulmonary hypertension (PH).
Methods
The study cohort consisted of 398 consecutive SSc patients, followed up for up to 15 years. Cox proportional hazards analysis with demographic, clinical, and laboratory characteristics as predictor variables was used to develop prediction models for pulmonary complications and survival.
Results
The overall survival estimate at the end of followup was 57% among patients with limited cutaneous SSc (lcSSc) and 50% among patients with diffuse cutaneous SSc (dcSSc) (P = 0.017). We found that greater age at disease onset, dcSSc, lower diffusing capacity for carbon monoxide (DLco), lower hemoglobin levels, higher serum creatinine levels, and the presence of PH or cardiac involvement were independent predictors of worse survival. Over the entire followup period, 42% of dcSSc patients and 22% of lcSSc patients developed clinically significant PF (P < 0.001). The variables that predicted clinically significant PF development were dcSSc, greater age at onset, lower forced vital capacity and DLco, and the presence of anti–topoisomerase I antibody, while the presence of anticentromere antibody was protective. There was no difference in cumulative incidence of PH between the 2 subsets—24% in lcSSc and 18% in dcSSc (P = 0.558). Incidence rates were 1–2% per year. The PH prediction model demonstrated that greater age at onset, increase in serum creatinine levels, lower DLco, and the presence of anti–RNA polymerase III or anti–U3 RNP antibodies were associated with increased risk of PH, while anti–topoisomerase I antibody positivity reduced the hazard.
Conclusion
Our study provides data on long‐term outcome of SSc and the timing and frequency of major organ complications. The predictive models we present could be used as clinical tools for patient risk stratification and could facilitate cohort enrichment for event‐driven studies.
► We studied arsenopyrite weathering reactions in rocks and sediments at mine site. ► Arsenopyrite oxidizes to scorodite, which dissolves incongruently to Fe hydroxide. ► Weathering of arsenopyrite ...to Fe hydroxide releases As to water. ► Dominant As reservoir in sediment is Fe hydroxide.
At a former As mine site, arsenopyrite oxidation has resulted in formation of scorodite and As-bearing iron hydroxide, both in host rock and mine tailings. Electron microprobe analysis documents that arsenopyrite weathers along two pathways: one that involves formation of sulfur, and one that does not. In both pathways, arsenopyrite oxidizes to form scorodite, which dissolves incongruently to form As-bearing iron hydroxides. From a mass balance perspective, arsenopyrite oxidation to scorodite conserves As, but as scorodite dissolves incongruently to iron hydroxides, As is released to solution, resulting in elevated As concentrations in the headwater stream adjacent to the site. The As-bearing iron hydroxide is the dominant solid phase reservoir of As in mine tailings and stream sediment, as suggested by sequential extraction. This As-bearing iron hydroxide is stable under the aerobic and pH 4–6 conditions at the site; however, changes in biogeochemical conditions resulting from sediment burial or future remedial efforts, which could promote As release from this reservoir due to reductive dissolution, should be avoided.
Sudden sensorineural hearing loss Schreiber, Benjamin E, MRCP; Agrup, Charlotte, PhD; Haskard, Dorian O, Prof ...
The Lancet (British edition),
04/2010, Letnik:
375, Številka:
9721
Journal Article
Recenzirano
Summary Sudden sensorineural hearing loss is usually unilateral and can be associated with tinnitus and vertigo. In most cases the cause is not identified, although various infective, vascular, and ...immune causes have been proposed. A careful examination is needed to exclude life threatening or treatable causes such as vascular events and malignant diseases, and patients should be referred urgently for further assessment. About half of patients completely recover, usually in about 2 weeks. Many treatments are used, including corticosteroids, antiviral drugs, and vasoactive and oxygen-based treatments. Although no treatment is proven, we recommend a short course of oral high-dose corticosteroids. There is much to learn about pathogenesis of sudden sensorineural hearing loss, and more clinical trials are needed to establish evidence-based management.
Information technology is finding an increasing role in the training of medical students. We compared information recall and student experience and preference after live lectures and video podcasts ...in undergraduate medical education.
We performed a crossover randomised controlled trial. 100 students were randomised to live lecture or video podcast for one clinical topic. Live lectures were given by the same instructor as the narrator of the video podcasts. The video podcasts comprised Powerpoint™ slides narrated using the same script as the lecture. They were then switched to the other group for a second clinical topic. Knowledge was assessed using multiple choice questions and qualitative information was collected using a questionnaire.
No significant difference was found on multiple choice questioning immediately after the session. The subjects enjoyed the convenience of the video podcast and the ability to stop, review and repeat it, but found it less engaging as a teaching method. They expressed a clear preference for the live lecture format.
We suggest that video podcasts are not ready to replace traditional teaching methods, but may have an important role in reinforcing learning and aiding revision.
Analysis of heart rate variability (HRV) is a recognized tool in the assessment of autonomic nervous system (ANS) activity. Indeed, both time and spectral analysis techniques enable us to obtain ...indexes that are related to the way the ANS regulates the heart rate. However, these techniques are limited in terms of the lack of thresholds of the numerical indexes, which is primarily due to high inter-subject variability. We proposed a new fetal HRV analysis method related to the parasympathetic activity of the ANS. The aim of this study was to evaluate the performance of our method compared to commonly used HRV analysis, with regard to i) the ability to detect changes in ANS activity and ii) inter-subject variability. This study was performed in seven sheep fetuses. In order to evaluate the sensitivity and specificity of our index in evaluating parasympathetic activity, we directly administered 2.5 mg intravenous atropine, to inhibit parasympathetic tone, and 5 mg propranolol to block sympathetic activity. Our index, as well as time analysis (root mean square of the successive differences; RMSSD) and spectral analysis (high frequency (HF) and low frequency (LF) spectral components obtained via fast Fourier transform), were measured before and after injection. Inter-subject variability was estimated by the coefficient of variance (%CV). In order to evaluate the ability of HRV parameters to detect fetal parasympathetic decrease, we also estimated the effect size for each HRV parameter before and after injections. As expected, our index, the HF spectral component, and the RMSSD were reduced after the atropine injection. Moreover, our index presented a higher effect size. The %CV was far lower for our index than for RMSSD, HF, and LF. Although LF decreased after propranolol administration, fetal stress index, RMSSD, and HF were not significantly different, confirming the fact that those indexes are specific to the parasympathetic nervous system. In conclusion, our method appeared to be effective in detecting parasympathetic inhibition. Moreover, inter-subject variability was much lower, and effect size higher, with our method compared to other HRV analysis methods.
In this review article, we consider the use of molecular oxygen in reactions mediated by polyoxometalates. Polyoxometalates are anionic metal oxide clusters of a variety of structures that are ...soluble in liquid phases and therefore amenable to homogeneous catalytic transformations. Often, they are active for electron transfer oxidations of a myriad of substrates and upon reduction can be reoxidized by molecular oxygen. For example, the phosphovanadomolybdate, H5PV2Mo10O40, can oxidize Pd(0) thereby enabling aerobic reactions catalyzed by Pd and H5PV2Mo10O40. In a similar vein, polyoxometalates can stabilize metal nanoparticles, leading to additional transformations. Furthermore, electron transfer oxidation of other substrates such as halides and sulfur-containing compounds is possible. More uniquely, H5PV2Mo10O40 and its analogues can mediate electron transfer-oxygen transfer reactions where oxygen atoms are transferred from the polyoxometalate to the substrate. This unique property has enabled correspondingly unique transformations involving carbon–carbon, carbon–hydrogen, and carbon–metal bond activation. The pathway for the reoxidation of vanadomolybdates with O2 appears to be an inner-sphere reaction, but the oxidation of one-electron reduced polyoxotungstates has been shown through intensive research to be an outer-sphere reaction. Beyond electron transfer and electron transfer–oxygen transfer aerobic transformations, there a few examples of apparent dioxygenase activity where both oxygen atoms are donated to a substrate.
Electrical resistivity imaging (ERI) and time domain reflectometry (TDR) were used to simultaneously measure resistivity and soil moisture at an experimental field site with the objective of ...quantifying soil moisture in 2D unsaturated zone profiles (>40
m long and 9
m deep). With a time-series data set and a modified form of Archie’s Law, we used bulk conductivity derived from ERI models of soil resistivity, pore water conductivity derived using an exchangeable cation proxy (Ca
+
Mg), and percent clay content of soils, to convert 2D ERI profiles into 2D soil moisture profiles. We optimized the model using 1D access-tube time domain reflectometry (TDR) derived soil moisture measurements. Results show that this approach can be used to quantify soil moisture in heterogeneous soils, and thus provides a useful method for measuring 2D soil moisture at a variety of field sites and scales.
Patients treated for medulloblastoma who experience posterior fossa syndrome (PFS) demonstrate increased risk for neurocognitive impairment at one year post diagnosis. The aim of the study was to ...examine longitudinal trajectories of neuropsychological outcomes in patients who experienced PFS compared with patients who did not.
Participants were 36 patients (22 males) who experienced PFS and 36 comparison patients (21 males) who were matched on age at diagnosis and treatment exposure but did not experience PFS. All patients underwent serial evaluation of neurocognitive functioning spanning 1 to 5 years post diagnosis.
The PFS group demonstrated lower estimated mean scores at 1, 3, and 5 years post diagnosis on measures of general intellectual ability, processing speed, broad attention, working memory, and spatial relations compared with the non-PFS group. The PFS group exhibited estimated mean scores that were at least one standard deviation below the mean for intellectual ability, processing speed, and broad attention across all time points and for working memory by 5 years post diagnosis. Processing speed was stable over time. Attention and working memory declined over time. Despite some change over time, caregiver ratings of executive function and behavior problem symptoms remained within the average range.
Compared with patients who do not experience PFS, patients who experience PFS exhibit greater neurocognitive impairment, show little recovery over time, and decline further in some domains. Findings highlight the particularly high risk for long-term neurocognitive problems in patients who experience PFS and the need for close follow-up and intervention.
Objective
Pulmonary hypertension (PH) is a serious complication of systemic sclerosis (SSc). In this study, we explored the prediction of short‐term risk for PH using serial pulmonary function tests ...(PFTs) and other disease features.
Methods
SSc patients in whom disease onset occurred ≥10 years prior to data retrieval and for whom autoantibody specificity and PFT data were available were included in this study. Mixed‐effects modeling was used to describe changes in PFTs over time. Landmarking was utilized to include serial assessments and stratified Cox proportional hazards regression analysis with landmarks as strata was used to develop the PH prediction models.
Results
We analyzed data from 1,247 SSc patients, 16.3% of whom were male and 35.8% of whom had diffuse cutaneous SSc. Anticentromere, antitopoisomerase, and anti–RNA polymerase antibodies were observed in 29.8%, 22.0%, and 11.4% of patients, respectively, and PH developed in 13.6% of patients. Over time, diffusing capacity for carbon monoxide (DLco) and carbon monoxide transfer coefficient (Kco) declined in all SSc patients (up to 1.5% per year) but demonstrated much greater annual decline (up to 4.5% and 4.8%, respectively) in the 5–7 years preceding PH diagnosis. Comparisons between multivariable models including either DLco, Kco, or forced vital capacity (FVC)/DLco ratio, demonstrated that both absolute values and change over the preceding year in those measurements were strongly associated with the risk of PH (hazard ratio HR 0.93 and 0.76 for Kco and its change; HR 0.90 and 0.96 for DLco and its change; and HR 1.08 and 2.01 for FVC/DLco ratio and its change; P < 0.001 for all). The Kco‐based model had the greatest discriminating ability (Harrell's C‐statistic 0.903).
Conclusion
Our findings strongly support the importance of PFT trends over time in identifying patients at risk of developing PH.
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