20 research outputs found
Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases
The production of peroxide and superoxide is an inevitable consequence of
aerobic metabolism, and while these particular "reactive oxygen species" (ROSs)
can exhibit a number of biological effects, they are not of themselves
excessively reactive and thus they are not especially damaging at physiological
concentrations. However, their reactions with poorly liganded iron species can
lead to the catalytic production of the very reactive and dangerous hydroxyl
radical, which is exceptionally damaging, and a major cause of chronic
inflammation. We review the considerable and wide-ranging evidence for the
involvement of this combination of (su)peroxide and poorly liganded iron in a
large number of physiological and indeed pathological processes and
inflammatory disorders, especially those involving the progressive degradation
of cellular and organismal performance. These diseases share a great many
similarities and thus might be considered to have a common cause (i.e.
iron-catalysed free radical and especially hydroxyl radical generation). The
studies reviewed include those focused on a series of cardiovascular, metabolic
and neurological diseases, where iron can be found at the sites of plaques and
lesions, as well as studies showing the significance of iron to aging and
longevity. The effective chelation of iron by natural or synthetic ligands is
thus of major physiological (and potentially therapeutic) importance. As
systems properties, we need to recognise that physiological observables have
multiple molecular causes, and studying them in isolation leads to inconsistent
patterns of apparent causality when it is the simultaneous combination of
multiple factors that is responsible. This explains, for instance, the
decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference
Evaluation of appendicitis risk prediction models in adults with suspected appendicitis
Background
Appendicitis is the most common general surgical emergency worldwide, but its diagnosis remains challenging. The aim of this study was to determine whether existing risk prediction models can reliably identify patients presenting to hospital in the UK with acute right iliac fossa (RIF) pain who are at low risk of appendicitis.
Methods
A systematic search was completed to identify all existing appendicitis risk prediction models. Models were validated using UK data from an international prospective cohort study that captured consecutive patients aged 16–45 years presenting to hospital with acute RIF in March to June 2017. The main outcome was best achievable model specificity (proportion of patients who did not have appendicitis correctly classified as low risk) whilst maintaining a failure rate below 5 per cent (proportion of patients identified as low risk who actually had appendicitis).
Results
Some 5345 patients across 154 UK hospitals were identified, of which two‐thirds (3613 of 5345, 67·6 per cent) were women. Women were more than twice as likely to undergo surgery with removal of a histologically normal appendix (272 of 964, 28·2 per cent) than men (120 of 993, 12·1 per cent) (relative risk 2·33, 95 per cent c.i. 1·92 to 2·84; P < 0·001). Of 15 validated risk prediction models, the Adult Appendicitis Score performed best (cut‐off score 8 or less, specificity 63·1 per cent, failure rate 3·7 per cent). The Appendicitis Inflammatory Response Score performed best for men (cut‐off score 2 or less, specificity 24·7 per cent, failure rate 2·4 per cent).
Conclusion
Women in the UK had a disproportionate risk of admission without surgical intervention and had high rates of normal appendicectomy. Risk prediction models to support shared decision‐making by identifying adults in the UK at low risk of appendicitis were identified
Selective Hydrogenation of Levulinic Acid Using Ru/C Catalysts Prepared by Sol-Immobilisation
A 1% Ru/C catalyst prepared by the sol immobilization method showed a high yield of γ-valerolactone from levulinic acid. We performed an optimization of the catalyst by varying the preparation variables involved in the sol immobilization method and detremined that the ratio of PVA, NaBH4 to Ru and heat treatment conditions play a crucial role in the synthesis of active and selective catalysts. By varying these parameters we have identified the optimum conditions for catalyst preparation by providing well dispersed nanoparticles of RuOx on the carbon support that are reducible under low reaction temperature and in turn gave an enhanced catalytic activity. In contrast to a catalyst prepared without using a PVA stabiliser, the use of a small amount PVA (PVA/Ru = 0.1) provided active nanoparticles, by controlling the steric size of the Ru nanoparticles. An optimum amount of NaBH4 was required in order to provide the reducible Ru species on the surface of catalyst and further increase in NaBH4 was found to cause a decline in activity that was related to the kinetics of nanoparticle formation during catalyst preparation. A variation of heat treatment temperature showed a corresponding decrease in catalytic activity linked with the sintering and an increase in particle size
The selenium jevels of mothers and their neonates using hair, breast milk, meconium, and maternal and umbilical cord blood in van basin
The objective of the present study is to calculate linear regressions between a mother and her child with respect to their selenium concentration (ng/g) in the following traits: maternal blood and umbilical cord blood, maternal and child hair, maternal milk and child umbilical cord blood, maternal milk and meconium, maternal blood plasma, and child meconium. The data were collected at Research Hospital of the University of Yüzüncü Yıl from 30 pairs of mothers and their newborn baby. The mean maternal serum Se level in 30 mothers was 68.52 ± 3.57 ng/g and cord plasma level was 119.90 ± 18.08 ng/g. The Se concentration in maternal and neonatal hair was 330.84 ± 39.03 and 1,124.76 ± 186.84 ng/g, respectively. The Se concentration of maternal milk at day 14 after delivery was determined as 68.63 ± 7.78 ng/g (n = 13) and the concentration of Se was 418.90 ± 45.49 ng/g (n = 22) for meconium of neonatal. There was no significant difference between maternal blood and milk Se levels. However, hair Se concentration was significantly higher than milk and maternal blood Se level. For each trait comparison, the average absolute difference in log10-transformed Se concentration was calculated between a mother and her child. The observed average absolute difference was compared with a test distribution of 1,000 resampled bootstrap averages where the number of samples was maintained but the relationship between a mother and her child was randomized among samples (α = 0.05).H. Sağmanlıgil Özdemir, F. Karadas, A. C. Pappas, P. Cassey, G. Oto and O. Tunce