A Novel Biosensor for Evaluation of Apoptotic or Necrotic Effects of Nitrogen Dioxide during Acute Pancreatitis in Rat

The direct and accurate estimation of nitric dioxide levels is an extremely laborious and technically demanding procedure in the molecular diagnostics of inflammatory processes. The aim of this work is to demonstrate that a stop-flow technique utilizing a specific spectroscopic biosensor can be used for detection of nanomolar quantities of NO2 in biological milieu. The use of novel compound cis-[Cr(C2O4)(AaraNH2)(OH2)2]+ increases NO2 estimation accuracy by slowing down the rate of NO2 uptake. In this study, an animal model of pancreatitis, where nitrosative stress is induced by either 3g/kg bw or 1.5 g/kg bw dose of l-arginine, was used. Biochemical parameters and morphological characteristics of acute pancreatitis were monitored, specifically assessing pancreatic acinar cell death mode, NO2 generation and cellular glutathione level. The severity of the process correlated positively with NO2 levels in pancreatic acinar cell cytosol samples, and negatively with cellular glutathione levels

Inactivation of pathogens on food and contact surfaces using ozone as a biocidal agent

This study focuses on the inactivation of a range of food borne pathogens using ozone as a biocidal agent. Experiments were carried out using Campylobacter jejuni, E. coli and Salmonella enteritidis in which population size effects and different treatment temperatures were investigate

In vitro expanded human CD4+CD25+ regulatory T cells suppress effector T cell proliferation.

Regulatory T cells (Tregs) have been shown to be critical in the balance between autoimmunity and tolerance and have been implicated in several human autoimmune diseases. However, the small number of Tregs in peripheral blood limits their therapeutic potential. Therefore, we developed a protocol that would allow for the expansion of Tregs while retaining their suppressive activity. We isolated CD4+CD25 hi cells from human peripheral blood and expanded them in vitro in the presence of anti-CD3 and anti-CD28 magnetic Xcyte Dynabeads and high concentrations of exogenous Interleukin (IL)-2. Tregs were effectively expanded up to 200-fold while maintaining surface expression of CD25 and other markers of Tregs: CD62L, HLA-DR, CCR6, and FOXP3. The expanded Tregs suppressed proliferation and cytokine secretion of responder PBMCs in co-cultures stimulated with anti-CD3 or alloantigen. Treg expansion is a critical first step before consideration of Tregs as a therapeutic intervention in patients with autoimmune or graft-versus-host disease

Neurotoxicity

Neurotoxins are natural or chemical compounds that can disturb the neurological system of mammals. The neurotoxic potential of a neurotoxin is a consequence that may occur if tissue concentrations surpass a particular threshold. Chemicals disrupt adult brain function by interfering with the structure and function of various neuronal pathways, circuits, and systems in diverse ways. Neurotoxicity - New Advances provides updated information about neurotoxicity and neurotoxic chemicals including nanomaterials and pesticides. It also discusses prevention and treatment strategies. This book is an instructive and valuable guide to understanding neurotoxicity and identifying neurotoxicity mechanisms and neurotoxic disorders

Antioxidant and DPPH-Scavenging Activities of Compounds and Ethanolic Extract of the Leaf and Twigs of Caesalpinia bonduc L. Roxb.

Antioxidant effects of ethanolic extract of Caesalpinia bonduc and its isolated bioactive compounds were evaluated in vitro. The compounds included two new cassanediterpenes, 1α,7α-diacetoxy-5α,6β-dihydroxyl-cass-14(15)-epoxy-16,12-olide (1)and 12α-ethoxyl-1α,14β-diacetoxy-2α,5α-dihydroxyl cass-13(15)-en-16,12-olide(2); and others, bonducellin (3), 7,4’-dihydroxy-3,11-dehydrohomoisoflavanone (4), daucosterol (5), luteolin (6), quercetin-3-methyl ether (7) and kaempferol-3-O-α-L-rhamnopyranosyl-(1Ç2)-β-D-xylopyranoside (8). The antioxidant properties of the extract and compounds were assessed by the measurement of the total phenolic content, ascorbic acid content, total antioxidant capacity and 1-1-diphenyl-2-picryl hydrazyl (DPPH) and hydrogen peroxide radicals scavenging activities.Compounds 3, 6, 7 and ethanolic extract had DPPH scavenging activities with IC50 values of 186, 75, 17 and 102 μg/ml respectively when compared to vitamin C with 15 μg/ml. On the other hand, no significant results were obtained for hydrogen peroxide radical. In addition, compound 7 has the highest phenolic content of 0.81±0.01 mg/ml of gallic acid equivalent while compound 8 showed the highest total antioxidant capacity with 254.31±3.54 and 199.82±2.78 μg/ml gallic and ascorbic acid equivalent respectively. Compound 4 and ethanolic extract showed a high ascorbic acid content of 2.26±0.01 and 6.78±0.03 mg/ml respectively.The results obtained showed the antioxidant activity of the ethanolic extract of C. bonduc and deduced that this activity was mediated by its isolated bioactive compounds

Mechanisms of interaction of non-thermal plasma with living cells

Thermal plasmas and lasers have been widely used in medicine to cut, ablate and cauterize tissues through heating; in contrast, non-thermal plasma produces various highly active molecules and atoms without heat. As a result, its effects on living cells and tissues could be selective and tunable. This makes non-thermal plasma very attractive for medical applications. However, despite several interesting demonstrations of non-thermal plasma in blood coagulation and tissue sterilization, the biological and physical mechanisms of its interaction with living cells are still poorly understood impeding further development of non-thermal plasma as a clinical tool. Although several possible mechanisms of interaction have been suggested, no systematic experimental work has been performed to verify these hypotheses.Using cells in culture, it is shown in this work that non-thermal plasma created by dielectric barrier discharge (DBD) has dose-dependent effects ranging from increasing cell proliferation to inducing apoptosis which are consistent with the effects of oxidative stress. DNA damage is chosen as a marker to assess the effects of oxidative stress in a quantitative manner. It is demonstrated here that plasma induced DNA damage as well as other effects ranging from cell proliferation to apoptosis are indeed due to production of intracellular reactive oxygen species (ROS). We found that DNA damage is initiated primarily by plasma generated active neutral species which cannot be attributed to ozone alone. Moreover, it is found that extracellular media and its components play a critical role in the transfer of the non-thermal plasma initiated oxidative stress into cells. Specifically, it is found that the peroxidation efficiency of amino acids is the sole predictor of the ability of the medium to transfer the oxidative stress induced by non-thermal plasma.Phosphorylation of H2AX, a DNA damage marker, following plasma treatment is found to be ATR dependent and ATM independent, suggesting that non-thermal plasma may induce formation of bulky lesions unlike ionizing radiation (IR) or H2O2 which primarily produce DNA double strand breaks. Moreover, it is found that the pathway by which plasma generated oxidative stress is transferred across cellular membranes does not involve lipid peroxidation by-products, although lipid peroxidation does occur.Ph.D., Electrical Engineering -- Drexel University, 201

Biological and Pharmacological Activity of Plant Natural Compounds II

The Special issue "Biological and Pharmacological Activity of Plant Natural Compounds II" is continuing the intriguing research on the use of natural plant products. The second edition follows the aim of the first one

Using an in vitro model of human cystic fibrosis airways to investigate bacterial strategies which inactivate defence mechanisms and increase infection

Cystic fibrosis (CF) is the most common inherited genetic condition amongst Caucasians and arises due to mutations in the cystic fibrosis transmembrane conductance regulator, a chloride channel expressed upon the apical surface of epithelia. Whilst CF is a multi-organ disease, the inability to clear dehydrated mucus from the airways predisposes individuals to the development of chronic bacterial infections, the main cause of morbidity and mortality in CF. Infection of CF airways is highly ordered, with Staphylococcus aureus predominating in the first decade of life, followed by Pseudomonas aeruginosa during adulthood. Two obstacles to the development of better treatments stem from an incomplete understanding of thepolymicrobial nature of CF airway infection and its impact upon interspecies and host-pathogen interactions, alongside the need for models which more closely mimic the CF lung and its unique environment. After characterising a panel of P. aeruginosa CF clinical isolates, this study sought to determine the impact of oxygen availability upon S. aureus-P. aeruginosa interspecies interactions, in light of evidence that mucus plugging within CF airways leads to regions of anoxia. Anoxia was shown to modulate S. aureus-P. aeruginosa community composition in planktonic co-culture and mixed species biofilms in an isolate-dependent manner. Further investigations into the mechanisms facilitating P. aeruginosa dominance suggest that the anti-staphylococcal agentis extracellular, >3 kDa in size and heat-resistant. Whilst pulmonary inflammation is a hallmark of CF, how airways respond to stimuli received during polymicrobial airway infections is poorly understood. Monolayers of CF and non-CF bronchial epithelia were challenged with S. aureus and/or P. aeruginosa extracellular products.CF airway epithelia exhibited a hyper-inflammatory phenotype at baseline compared to non-CF epithelia. Furthermore, only co-stimulation of non-CF epithelia with both pathogens, enhanced the IL-6 and IL-8 response beyond that measured following single bacterial challenges. Finally, CF and non-CF airway epithelia grown at air-liquid interface in the presence of fibroblasts were used to mimic the sequential nature of CF infection. Binding studies demonstrated that prior infection with S. aureus enhanced P. aeruginosa binding to the CF airway model in an isolate-specific manner, a finding not seen in the non-CF airway model. These studies demonstrate that S. aureus-P. aeruginosa interactions are likely to influence the CF microbiome, airway inflammation, airway colonisation and ultimately, disease progression.It is hoped that the models used here can be employed in future studies to understand the complex interspecies and host-pathogen interactions that occur in CF, with the aim to identify novel targets and treatments to combat these life limiting infections

Electrochemical measurement of nitric oxide from biological systems

Nitric oxide (NO) is known to be involved in a number of physiological processes, including the immune response. As such, its role in severe infection and sepsis has been investigated, but previous measurement techniques have relied on complicated instrumentation or the quantification of NO byproducts (e.g., nitrate and nitrite). Herein, the fabrication of a microfluidic amperometric sensor for the direct detection of NO in whole blood is described. These sensors were used to evaluate the potential of NO and nitrosothiols (a stable transporter) as prognostic and/or diagnostic biomarkers for infection and sepsis. The microfluidic devices facilitated the selective electrochemical measurement of NO in small volumes of blood at the point-of-care, with adequate sensitivity and limits of detection achieved in buffer, wound fluid, and whole blood. A green (530 nm) light-emitting diode was coupled to the device to enable photolysis of S-nitrosothiol species with subsequent NO detection. While inefficient photolysis prevented the measurement of nitrosothiols in whole blood, detection in serum was achieved. A porcine model of sepsis permitted monitoring of temporal changes in NO and nitrosothiols throughout disease progression. While increases in NO were observed concurrently with other indicators (e.g., increased blood lactate and base deficit), the accumulation of nitrosothiols was observed hours prior to the onset of other symptoms, despite a dramatic drop in the circulating white blood cells that produce NO. A murine model of sepsis was utilized to understand the effects of bacterial virulence and immune suppression on NO during an infection. A non-lethal pneumonia with Pseudomonas aeruginosa resulted in elevated NO levels at 72 h that returned to baseline concentrations after 1 wk. A more virulent bacterium, Klebsiella pneumoniae, resulted in much greater increases in NO, reflecting its pathogenicity. Conversely, in a murine model of post-burn immune suppression and infection, blood NO concentrations remained unchanged relative to uninfected animals despite increased infection severity. Nitric oxide-selective microelectrodes were also used to study NO release at the single cell level, from both immune cells and neurons. Upregulation of carbon monoxide production by the macrophages was demonstrated to inhibit their ability to release NO following immune stimulation. Additionally, the concentration and kinetics of NO release from neurons were determined.Doctor of Philosoph

Leishmaniasis

Leishmaniasis is a major global health challenge, affecting approximately 12 million of the poorest people in 100 countries. It is a deforming and fatal disease in the visceral form. Therapies for leishmaniasis are numerically restricted, basically consisting of the administration of miltefosine, pentavalent antimonials, amphotericin B, or pentamidine. This is an important vulnerability against therapy efficiency that must be overcome by the scientific community. This book discusses important aspects of the disease, such as treatment, epidemiology, and molecular and cell biology. The information contained herein is important for young researchers as they seek to develop safe and effective treatments for this neglected tropical disease