92 research outputs found

    Urticarial vasculitis in northern Spain: clinical study of 21 cases

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    Urticarial vasculitis (UV) is a subset of cutaneous vasculitis (CV), characterized clinically by urticarial skin lesions of more than 24 hours' duration and histologically by leukocytoclastic vasculitis. We assessed the frequency, clinical features, treatment, and outcome of a series of patients with UV. We conducted a retrospective study of patients with UV included in a large series of unselected patients with CV from a university hospital. Of 766 patients with CV, UV was diagnosed in 21 (2.7%; 9 male and 12 female patients; median age, 35 yr; range, 1-78 yr; interquartile range, 5-54 yr). Eight of the 21 cases were aged younger than 20 years old. Potential precipitating factors were upper respiratory tract infections and drugs (penicillin) (n = 4; in all cases in patients aged <20 yr), human immunodeficiency virus (HIV) infection (n = 1), and malignancy (n = 1). Besides urticarial lesions, other features such as palpable purpura (n = 7), arthralgia and/or arthritis (n = 13), abdominal pain (n = 2), nephropathy (n = 2), and peripheral neuropathy (n = 1) were observed. Hypocomplementemia (low C4) with low C1q was disclosed in 2 patients. Other abnormal laboratory findings were leukocytosis (n = 7), increased erythrocyte sedimentation rate (n = 6), anemia (n = 4), and antinuclear antibody positivity (n = 2). Treatment included corticosteroids (n = 12), antihistaminic drugs (n = 6), chloroquine (n = 4), nonsteroidal antiinflammatory drugs (n = 3), colchicine (n = 2), and azathioprine (n = 1). After a median follow-up of 10 months (interquartile range, 2-38 mo) recurrences were observed in 4 patients. Apart from 1 patient who died because of an underlying malignancy, the outcome was good with full recovery in the remaining patients. In conclusion, our results indicate that UV is rare but not exceptional. In children UV is often preceded by an upper respiratory tract infection. Urticarial lesions and joint manifestations are the most frequent clinical manifestation. Low complement serum levels are observed in a minority of cases. The prognosis is generally good, but depends on the underlying disease

    A New Family of Lysozyme Inhibitors Contributing to Lysozyme Tolerance in Gram-Negative Bacteria

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    Lysozymes are ancient and important components of the innate immune system of animals that hydrolyze peptidoglycan, the major bacterial cell wall polymer. Bacteria engaging in commensal or pathogenic interactions with an animal host have evolved various strategies to evade this bactericidal enzyme, one recently proposed strategy being the production of lysozyme inhibitors. We here report the discovery of a novel family of bacterial lysozyme inhibitors with widespread homologs in gram-negative bacteria. First, a lysozyme inhibitor was isolated by affinity chromatography from a periplasmic extract of Salmonella Enteritidis, identified by mass spectrometry and correspondingly designated as PliC (periplasmic lysozyme inhibitor of c-type lysozyme). A pliC knock-out mutant no longer produced lysozyme inhibitory activity and showed increased lysozyme sensitivity in the presence of the outer membrane permeabilizing protein lactoferrin. PliC lacks similarity with the previously described Escherichia coli lysozyme inhibitor Ivy, but is related to a group of proteins with a common conserved COG3895 domain, some of them predicted to be lipoproteins. No function has yet been assigned to these proteins, although they are widely spread among the Proteobacteria. We demonstrate that at least two representatives of this group, MliC (membrane bound lysozyme inhibitor of c-type lysozyme) of E. coli and Pseudomonas aeruginosa, also possess lysozyme inhibitory activity and confer increased lysozyme tolerance upon expression in E. coli. Interestingly, mliC of Salmonella Typhi was picked up earlier in a screen for genes induced during residence in macrophages, and knockout of mliC was shown to reduce macrophage survival of S. Typhi. Based on these observations, we suggest that the COG3895 domain is a common feature of a novel and widespread family of bacterial lysozyme inhibitors in gram-negative bacteria that may function as colonization or virulence factors in bacteria interacting with an animal host

    Acute kidney injury in children

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    Acute kidney injury (AKI) (previously called acute renal failure) is characterized by a reversible increase in the blood concentration of creatinine and nitrogenous waste products and by the inability of the kidney to regulate fluid and electrolyte homeostasis appropriately. The incidence of AKI in children appears to be increasing, and the etiology of AKI over the past decades has shifted from primary renal disease to multifactorial causes, particularly in hospitalized children. Genetic factors may predispose some children to AKI. Renal injury can be divided into pre-renal failure, intrinsic renal disease including vascular insults, and obstructive uropathies. The pathophysiology of hypoxia/ischemia-induced AKI is not well understood, but significant progress in elucidating the cellular, biochemical and molecular events has been made over the past several years. The history, physical examination, and laboratory studies, including urinalysis and radiographic studies, can establish the likely cause(s) of AKI. Many interventions such as ‘renal-dose dopamine’ and diuretic therapy have been shown not to alter the course of AKI. The prognosis of AKI is highly dependent on the underlying etiology of the AKI. Children who have suffered AKI from any cause are at risk for late development of kidney disease several years after the initial insult. Therapeutic interventions in AKI have been largely disappointing, likely due to the complex nature of the pathophysiology of AKI, the fact that the serum creatinine concentration is an insensitive measure of kidney function, and because of co-morbid factors in treated patients. Improved understanding of the pathophysiology of AKI, early biomarkers of AKI, and better classification of AKI are needed for the development of successful therapeutic strategies for the treatment of AKI

    Copper and tin isotopic analysis of ancient bronzes for archaeological investigation: development and validation of a suitable analytical methodology

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    Although in many cases Pb isotopic analysis can be relied on for provenance determination of ancient bronzes, sometimes the use of “non-traditional” isotopic systems, such as those of Cu and Sn, is required. The work reported on in this paper aimed at revising the methodology for Cu and Sn isotope ratio measurements in archaeological bronzes via optimization of the analytical procedures in terms of sample pre-treatment, measurement protocol, precision, and analytical uncertainty. For Cu isotopic analysis, both Zn and Ni were investigated for their merit as internal standard (IS) relied on for mass bias correction. The use of Ni as IS seems to be the most robust approach as Ni is less prone to contamination, has a lower abundance in bronzes and an ionization potential similar to that of Cu, and provides slightly better reproducibility values when applied to NIST SRM 976 Cu isotopic reference material. The possibility of carrying out direct isotopic analysis without prior Cu isolation (with AG-MP-1 anion exchange resin) was investigated by analysis of CRM IARM 91D bronze reference material, synthetic solutions, and archaeological bronzes. Both procedures (Cu isolation/no Cu isolation) provide similar δ 65Cu results with similar uncertainty budgets in all cases (±0.02–0.04 per mil in delta units, k = 2, n = 4). Direct isotopic analysis of Cu therefore seems feasible, without evidence of spectral interference or matrix-induced effect on the extent of mass bias. For Sn, a separation protocol relying on TRU-Spec anion exchange resin was optimized, providing a recovery close to 100 % without on-column fractionation. Cu was recovered quantitatively together with the bronze matrix with this isolation protocol. Isotopic analysis of this Cu fraction provides δ 65Cu results similar to those obtained upon isolation using AG-MP-1 resin. This means that Cu and Sn isotopic analysis of bronze alloys can therefore be carried out after a single chromatographic separation using TRU-Spec resin. Tin isotopic analysis was performed relying on Sb as an internal standard used for mass bias correction. The reproducibility over a period of 1 month (n = 42) for the mass bias-corrected Sn isotope ratios is in the range of 0.06–0.16 per mil (2 s), for all the ratios monitored

    Minority Stockholders\u27 Protection in a New Corporate Control Law: Market Implications in an Emerging Economy

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    This paper analyzes the effect of a new corporate governance law in the emerging capital market of Chile to determine if capital markets perceived the intended protection of minority stockholders against wealth expropriation as effective. The unique nature of the new law allowed for voluntary adoption during the initial three-year period, after which it became mandatory. We find no evidence of superior abnormal returns for those firms voluntarily adopting the new law versus those forced to accept the new law as it became mandatory. Trading volume also increased for those not adopting and declined for those that did voluntarily adopt. These results indicate that the capital markets did not perceive voluntary adoption of the new law as effective protection for minority shareholders. We also find a greater presence of institutional investors in the ownership structure of those firms not voluntarily adopting the new law, indicating their monitoring role by investing in firms with better corporate governance practices. Our results suggest that, in the Chilean case, the presence of strong institutional investors is as effective a corporate governance mechanism as is the new law
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