12 research outputs found
Non-aqueous electrolyte solutions in chemistry and modern technology
In this paper a brief survey is given of the properties of non-aqueous electrolyte solutions and their applications in chemistry and technology without going into the details of theory. Specific solvent-solute interactions and the role of the solvent beyond its function as a homogenous isotropic medium are stressed. Taking into account Parker's statement1) ldquoScientists nowadays are under increasing pressure to consider the relevance of their research, and rightly sordquo we have included examples showing the increasing industrial interest in non-aqueous electrolyte solutions.
The concepts and results are arranged in two parts. Part A concerns the fundamentals of thermodynamics, transport processes, spectroscopy and chemical kinetics of non-aqueous solutions and some applications in these fields. Part B describes their use in various technologies such as high-energy batteries, non-emissive electro-optic displays, photoelectrochemical cells, electrodeposition, electrolytic capacitors, electro-organic synthesis, metallurgic processes and others.
Four Appendices are added. Appendix A gives a survey on the most important non-aqueous solvents, their physical properties and correlation parameters, and the commonly used abbreviations. Appendices B and C show the mathematical background of the general chemical model. The Symbols and abbreviations of the text are listed and explained in Appendix D
Elevated serum levels of matrix metalloproteinase-9 (MMP-9) in Kawasaki disease
Matrix metalloproteinases (MMPs) play an important role in the progression of tumour cells and the invasion of inflammatory cells by degrading the extracellular matrix. In the MMP family, MMP-9 gelatinase is thought to contribute to the pathogenesis of inflammatory arteritis by disrupting the elastic lamina. The aim of the present study is to investigate the potential role of MMP-9 in Kawasaki disease (KD), an acute type of systemic vasculitis in children. We studied the total levels of MMP-9 (free proMMP-9 and free MMP-9) in the sera using a new assay system and the expression of MMP-9 mRNA in the leucocytes using reverse transcription-polymerase chain reaction in 18 patients with KD, 10 patients with sepsis and 10 healthy children (HC). The serum MMP-9 levels were significantly higher (P < 0·01) in the acute phase of KD than in the acute phase of sepsis and HC. In the time course of KD, the serum MMP-9 levels decreased significantly (P < 0·01) from the subacute through the convalescent phases. In the acute phase of KD, the serum MMP-9 levels showed a significantly positive correlation (P < 0·05) with the circulating leucocyte counts, especially the neutrophil counts. Furthermore, the expression of MMP-9 mRNA in the circulating leucocytes increased in the acute phase of KD and decreased from the subacute through the convalescent phases. These findings indicate that an excessive amount of MMP-9 is present in the plasma during the acute phase of KD, thus suggesting that circulating leucocytes may be a source of the MMP-9 secreted into the circulation
Inflammatory Mediators in Dengue Virus Infection in Children: Interleukin-8 and Its Relationship to Neutrophil Degranulation
The chemokine interleukin-8 (IL-8) has chemoattractant activity for neutrophils and is able to activate and degranulate these cells. We investigated whether IL-8 may exert these effects in children with dengue virus infection. Circulating levels of IL-8, neutrophilic elastase (a constituent of the azurophilic granula of neutrophils), and lactoferrin, released from specific granula, were measured in 186 children with dengue virus infection, 33 healthy children as negative controls and 11 children with bacterial infections as positive controls. Levels of IL-8 on admission were elevated in 71% of the dengue patients, while the elastase and lactoferrin levels were increased in 68 and 17% of patients, respectively. These levels were significantly higher than in healthy children (P < 0.05) for IL-8 and elastase but not for lactoferrin (by the Wilcoxon-Mann-Whitney [WMW] U test). Similar levels of IL-8 were found in patients with bacterial infections. Levels of IL-8 and elastase in patients with shock were significantly higher than in patients without shock (P = 0.02; WMW), but those of lactoferrin were not. IL-8 correlated with elastase and lactoferrin (r = 0.19 and P = 0.009 versus r = 0.24 and P = 0.001, respectively; two-tailed Spearman rank correlation). Thus, IL-8 levels are increased in most patients with dengue virus infection and correlate with degranulation of neutrophils as well as with some clinical and hemodynamic variables. These findings suggest a role for IL-8 in the pathogenesis of dengue virus infection
Delayed apoptosis of circulating neutrophils in Kawasaki disease
Circulating polymorphonuclear neutrophils (PMNs) are known to increase in number and are functionally activated in the acute phase of Kawasaki disease (KD). In the present study, we investigated whether the apoptosis of PMNs is deregulated in KD. When the isolated PMNs were cultured in vitro, the proportions of spontaneous apoptotic PMNs (annexin V+ cells and cells with fragmented DNA) were found to be significantly lower (P < 0·01) in the patients with KD (n = 25) than in the patients with a bacterial infection (n = 20) or a viral infection (n = 20), or in healthy children (n = 20). The proportion of circulating Fas-positive PMNs was also significantly lower (P < 0·01) in the acute KD patients than in the other groups. In the acute phase of KD, the proportion of spontaneous apoptotic PMNs showed a significant positive correlation (P < 0·01) with the proportions of circulating Fas-positive PMNs. Furthermore, the agonistic anti-Fas MoAb (CH-11) induced a significant increase in the proportion of apoptotic PMNs in the patients with a viral infection and healthy children, but not in either the patients with KD or the patients with a bacterial infection. In the intracellular expression of anti- and pro-apoptotic proteins, the A1/Bax ratio was significantly higher in acute KD than in the other groups. These findings indicate that PMN apoptosis is inhibited during the acute phase of KD and also suggest that both the resistance against the Fas-mediated death signal and the down-regulation of the mitochondrial apoptotic signalling pathway due to an altered balance of Bcl-2 protein expression are responsible for the delayed PMN apoptosis
Measurement Issues in Health Disparities Research
BACKGROUND: Racial and ethnic disparities in health and health care have been documented; the elimination of such disparities is currently part of a national agenda. In order to meet this national objective, it is necessary that measures identify accurately the true prevalence of the construct of interest across diverse groups. Measurement error might lead to biased results, e.g., estimates of prevalence, magnitude of risks, and differences in mean scores. Addressing measurement issues in the assessment of health status may contribute to a better understanding of health issues in cross-cultural research. OBJECTIVE: To provide a brief overview of issues regarding measurement in diverse populations. FINDINGS: Approaches used to assess the magnitude and nature of bias in measures when applied to diverse groups include qualitative analyses, classic psychometric studies, as well as more modern psychometric methods. These approaches should be applied sequentially, and/or iteratively during the development of measures. CONCLUSIONS: Investigators performing comparative studies face the challenge of addressing measurement equivalence, crucial for obtaining accurate results in cross-cultural comparisons