scholarly journals Immobilization of Allantoinase for the Development of an Optical Biosensor of Oxidative Stress States

Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 196
Author(s):  
Marialaura Marchetti ◽  
Luca Ronda ◽  
Riccardo Percudani ◽  
Stefano Bettati
Keyword(s):  
Oxidative Stress ◽  
Silica Gel ◽  
Biological Fluids ◽  
Sol Gel ◽  
Catalytic Efficiency ◽  
Optical Biosensor ◽  
Oxygen Species ◽  
Chemical Assay ◽  
Stress States ◽  
Gel Preparation

Allantoin, the natural end product of purine catabolism in mammals, is non-enzymatically produced from the scavenging of reactive oxygen species through the degradation of uric acid. Levels of allantoin in biological fluids are sensitively influenced by the presence of free radicals, making this molecule a candidate marker of acute oxidative stress in clinical analyses. With this aim, we exploited allantoinase—the enzyme responsible for allantoin hydrolization in plants and lower organisms—for the development of a biosensor exploiting a fast enzymatic-chemical assay for allantoin quantification. Recombinant allantoinase was entrapped in a wet nanoporous silica gel matrix and its structural properties, function, and stability were characterized through fluorescence spectroscopy and circular dichroism measurements, and compared to the soluble enzyme. Physical immobilization in silica gel minimally influences the structure and the catalytic efficiency of entrapped allantoinase, which can be reused several times and stored for several months with good activity retention. These results, together with the relative ease of the sol-gel preparation and handling, make the encapsulated allantoinase a good candidate for the development of an allantoin biosensor.

scholarly journals Sol-Gel Preparation of Organic Colorant-Doped Silica Gel and its Properties.

1995 ◽  
Vol 29 (2) ◽  
pp. 154-162
Author(s):  
Ryuichi Inaba ◽  
Yoshihito Tanaka ◽  
Eiichi Saito ◽  
Yasuo Ohshima ◽  
Yoshio Fujiyama
Keyword(s):  
Silica Gel ◽  
Sol Gel ◽  
Gel Preparation

Sol—gel preparation of silica gel monoliths

1996 ◽  
Vol 201 (1-2) ◽  
pp. 150-152 ◽  
Author(s):  
V.K. Parashar ◽  
V. Raman ◽  
O.P. Bahl
Keyword(s):  
Silica Gel ◽  
Sol Gel ◽  
Silica Gel Monoliths ◽  
Gel Preparation

Sol–Gel Preparation and Hg(II) Adsorption Properties of Silica-Gel Supported Low Generation Polyamidoamine Dendrimers Polymer Adsorbents

2014 ◽  
Vol 53 (8) ◽  
pp. 2878-2888 ◽  
Author(s):  
Xiaomei Sun ◽  
Rongjun Qu ◽  
Changmei Sun ◽  
Ying Zhang ◽  
Shaoying Sun ◽  
...  
Keyword(s):  
Silica Gel ◽  
Sol Gel ◽  
Adsorption Properties ◽  
Polyamidoamine Dendrimers ◽  
Gel Preparation

Clinical aspects of reactive oxygen and nitrogen species

2004 ◽  
Vol 71 ◽  
pp. 121-133 ◽  
Author(s):  
Ascan Warnholtz ◽  
Maria Wendt ◽  
Michael August ◽  
Thomas Münzel
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Risk Factor ◽  
Endothelial Dysfunction ◽  
Vascular Tissue ◽  
Rapid Development ◽  
Reactive Oxygen ◽  
Clinical Aspects ◽  
No Production ◽  
Oxygen Species

Endothelial dysfunction in the setting of cardiovascular risk factors, such as hypercholesterolaemia, hypertension, diabetes mellitus and chronic smoking, as well as in the setting of heart failure, has been shown to be at least partly dependent on the production of reactive oxygen species in endothelial and/or smooth muscle cells and the adventitia, and the subsequent decrease in vascular bioavailability of NO. Superoxide-producing enzymes involved in increased oxidative stress within vascular tissue include NAD(P)H-oxidase, xanthine oxidase and endothelial nitric oxide synthase in an uncoupled state. Recent studies indicate that endothelial dysfunction of peripheral and coronary resistance and conductance vessels represents a strong and independent risk factor for future cardiovascular events. Ways to reduce endothelial dysfunction include risk-factor modification and treatment with substances that have been shown to reduce oxidative stress and, simultaneously, to stimulate endothelial NO production, such as inhibitors of angiotensin-converting enzyme or the statins. In contrast, in conditions where increased production of reactive oxygen species, such as superoxide, in vascular tissue is established, treatment with NO, e.g. via administration of nitroglycerin, results in a rapid development of endothelial dysfunction, which may worsen the prognosis in patients with established coronary artery disease.

Danshensu Rescues Ischemia/Reperfusion Caused Human Hepatocyte Death

2018 ◽  
Vol 17 (2) ◽  
pp. 117-121
Author(s):  
Sun Maw-Sheng ◽  
Liang Chun-Ya ◽  
Hsieh Po-Chun ◽  
Kuo Chan-Yen
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Caspase 3 ◽  
Ischemia Reperfusion ◽  
Oxygen Species ◽  
Good Strategy ◽  
Ros Accumulation ◽  
Dichlorofluorescin Diacetate ◽  
Hepatocyte Damage ◽  
Hepatocyte Death

Apoptosis of hepatocyte, under ischemia/reperfusion (IR) conditions, has been identified as an essential process in the progression of liver transplantation. Under these conditions, mitochondria can become a threat to the cell because of their capacity to generate reactive oxygen species (ROS). Additionally, ROS overproduction may induce inflammation. As ROS accumulation appears to cause hepatocyte damage or death, there has been considerable interest in identifying the candidate natural products involved and in developing strategies to reduce oxidative stress. In this study, we use Danshensu as a candidate product to speculate whether has the protective effect on apoptotic hepatocyte upon IR. To speculate the apoptotic phenomena was reversed by Danshensu, we detected the p53, cleaved-caspase 3 expression by western blotting, as well as caspase-3 activity. Additionally, we analyzed the ROS levels by 2′,7′-dichlorofluorescin diacetate (DCF-DA) staining. We also detected the cell viability by WST-1. Results showed that Danshensu alleviated hypoxia-caused cell apoptosis via ROS overproduction. We suggested that Danshensu is a good strategy for treating hepatocyte damage upon IR.

Assessment of Superoxide Dismutase and Catalase Evolution in Different Stages of an Experimental Endometriosis

2017 ◽  
Vol 68 (6) ◽  
pp. 1381-1383
Author(s):  
Allia Sindilar ◽  
Carmen Lacramioara Zamfir ◽  
Eusebiu Viorel Sindilar ◽  
Alin Constantin Pinzariu ◽  
Eduard Crauciuc ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Superoxide Dismutase ◽  
Antioxidant Enzymes ◽  
Reproductive Function ◽  
Female Rats ◽  
Oxygen Species ◽  
Efficient Treatment ◽  
Endometrial Cells ◽  
Gynecological Disorder ◽  
The Impact

Endometriosis is described as a gynecological disorder characterized by the presence of endometrial tissue outside the uterus; extensively explored because of its increasing incidency, with an indubitable diagnostic only after invasive surgery, with no efficient treatment, it has still many aspects to be elucidated. A growing body of facts sustain oxidative stress as a crucial factor between the numerous incriminated factors implicated in endometriosis ethiopathogeny. Reactive oxygen species(ROS) act to decline reproductive function. Our study intends to determine if an experimental model of endometriosis may be useful to assess the impact of oxidative stress on endometrial cells; we have used a murine model of 18 adult Wistar female rats. A fragment from their left uterine horn was implanted in the abdominal wall. After 4 weeks, a laparatomy was performed, 5 endometrial implants were removed, followed by biochemical tissue assay of superoxide dismutase(SOD) and catalase(CAT). At the end of the experiment, the rats were sacrificed, the implants were removed for histopathological exam and biochemical assay of antioxidant enzymes. The results revealed decreased levels of antioxidant enzymes, pointing on significant oxidative stress involvement.

Oxidative Stress Levels, JAK2V617F Mutational Status and Thrombotic Complications in Patients with Essential Thrombocythemia

2019 ◽  
Vol 70 (8) ◽  
pp. 2822-2825 ◽  
Author(s):  
Cornel Moisa ◽  
Mihnea Alexandru Gaman ◽  
Camelia Cristina Diaconu ◽  
Amelia Maria Gaman
Keyword(s):  
Oxidative Stress ◽  
Essential Thrombocythemia ◽  
Myeloproliferative Neoplasm ◽  
Oxygen Species ◽  
Mutational Status ◽  
Increased Risk ◽  
Stress Levels ◽  
Total Antioxidant ◽  
Thrombotic Complications ◽  
The Relationship

Essential thrombocythemia (ET) is a BCR-ABL1-negative myeloproliferative neoplasm associated with thrombotic and haemorrhagic complications. Reactive oxygen species (ROS) overexpression induces a growth advantage to JAK2V617F-positive clones and, in association with a higher number of immature platelets, leukocytosis, and additional cardiovascular risk factors, leads to an increased risk for thrombotic events. We evaluated oxidative stress by measuring ROS levels and the total antioxidant capacity (TAC) in 62 ET patients and investigated the relationship between oxidative stress, JAK2V617F mutational status and the development of thrombotic events. We found higher oxidative stress levels in JAK2V617F-positive vs. JAK2V617F-negative ET cases with no significant differences between homozygous and heterozygous genotypes. Increased ROS levels and thrombotic events were more frequent in ET patients with old age at diagnosis, higher haematocrit levels or leukocytosis.

Efficient Micromixing for Continuous Biodiesel Production from Jatropha Oil

2018 ◽  
Vol 9 (1) ◽  
pp. 133-139
Author(s):  
Waleed S. Mohammed ◽  
Ahmed H. El-Shazly ◽  
Marwa F. Elkady ◽  
Masahiro Ohshima
Keyword(s):  
Methyl Esters ◽  
Continuous Process ◽  
Sol Gel ◽  
Average Diameter ◽  
Biodiesel Production ◽  
High Mass ◽  
Molar Ratio ◽  
Jatropha Oil ◽  
Energy Deficiency ◽  
Gel Preparation

Introduction: The utilization of biodiesel as an alternative fuel is turning out to be progressively famous these days because of worldwide energy deficiency. The enthusiasm for utilizing Jatropha as a non-edible oil feedstock is quickly developing. The performance of the base catalyzed methanolysis reaction could be improved by a continuous process through a microreactor in view of the high mass transfer coefficient of this technique. Materials & Methods: Nanozirconium tungstovanadate, which was synthetized using sol-gel preparation method, was utilized in a complementary step for biodiesel production process. The prepared material has an average diameter of 0.066 &µm. Results: First, the NaOH catalyzed methanolysis of Jatropha oil was investigated in a continuous microreactor, and the efficient mixing over different mixers and its impact on the biodiesel yield were studied under varied conditions. Second, the effect of adding the nanocatalyst as a second stage was investigated. Conclusion: The maximum percentage of produced methyl esters from Jatropha oil was 98.1% using a methanol/Jatropha oil molar ratio of 11 within 94 s using 1% NaOH at 60 &°C. The same maximum conversion ratio was recorded with the nanocatalyst via only 0.3% NaOH.

scholarly journals 4-Hydroxychalcone Induces Cell Death via Oxidative Stress in MYCN-Amplified Human Neuroblastoma Cells

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Amnah M. Alshangiti ◽  
Eszter Tuboly ◽  
Shane V. Hegarty ◽  
Cathal M. McCarthy ◽  
Aideen M. Sullivan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Cell Death ◽  
Cytotoxic Effect ◽  
Neuroblastoma Cells ◽  
Reactive Oxygen ◽  
Prognostic Indicator ◽  
Oxygen Species ◽  
Human Neuroblastoma Cells ◽  
Human Neuroblastoma

Neuroblastoma is an embryonal malignancy that arises from cells of sympathoadrenal lineage during the development of the nervous system. It is the most common pediatric extracranial solid tumor and is responsible for 15% of childhood deaths from cancer. Fifty percent of cases are diagnosed as high-risk metastatic disease with a low overall 5-year survival rate. More than half of patients experience disease recurrence that can be refractory to treatment. Amplification of the MYCN gene is an important prognostic indicator that is associated with rapid disease progression and a poor prognosis, highlighting the need for new therapeutic approaches. In recent years, there has been an increasing focus on identifying anticancer properties of naturally occurring chalcones, which are secondary metabolites with variable phenolic structures. Here, we report that 4-hydroxychalcone is a potent cytotoxin for MYCN-amplified IMR-32 and SK-N-BE (2) neuroblastoma cells, when compared to non-MYCN-amplified SH-SY5Y neuroblastoma cells and to the non-neuroblastoma human embryonic kidney cell line, HEK293t. Moreover, 4-hydroxychalcone treatment significantly decreased cellular levels of the antioxidant glutathione and increased cellular reactive oxygen species. In addition, 4-hydroxychalcone treatment led to impairments in mitochondrial respiratory function, compared to controls. In support of this, the cytotoxic effect of 4-hydroxychalcone was prevented by co-treatment with either the antioxidant N-acetyl-L-cysteine, a pharmacological inhibitor of oxidative stress-induced cell death (IM-54) or the mitochondrial reactive oxygen species scavenger, Mito-TEMPO. When combined with the anticancer drugs cisplatin or doxorubicin, 4-hydroxychalcone led to greater reductions in cell viability than was induced by either anti-cancer agent alone. In summary, this study identifies a cytotoxic effect of 4-hydroxychalcone in MYCN-amplified human neuroblastoma cells, which rationalizes its further study in the development of new therapies for pediatric neuroblastoma.

scholarly journals Oxidative Stress in the Tumor Microenvironment and Its Relevance to Cancer Immunotherapy

Cancers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 986
Author(s):  
Nada S. Aboelella ◽  
Caitlin Brandle ◽  
Timothy Kim ◽  
Zhi-Chun Ding ◽  
Gang Zhou
Keyword(s):  
Oxidative Stress ◽  
Tumor Microenvironment ◽  
Cancer Cells ◽  
Redox Homeostasis ◽  
Tumor Rejection ◽  
Oxygen Species ◽  
Antitumor Effects ◽  
Key Drivers ◽  
Cancer Immunotherapies ◽  
The Impact

It has been well-established that cancer cells are under constant oxidative stress, as reflected by elevated basal level of reactive oxygen species (ROS), due to increased metabolism driven by aberrant cell growth. Cancer cells can adapt to maintain redox homeostasis through a variety of mechanisms. The prevalent perception about ROS is that they are one of the key drivers promoting tumor initiation, progression, metastasis, and drug resistance. Based on this notion, numerous antioxidants that aim to mitigate tumor oxidative stress have been tested for cancer prevention or treatment, although the effectiveness of this strategy has yet to be established. In recent years, it has been increasingly appreciated that ROS have a complex, multifaceted role in the tumor microenvironment (TME), and that tumor redox can be targeted to amplify oxidative stress inside the tumor to cause tumor destruction. Accumulating evidence indicates that cancer immunotherapies can alter tumor redox to intensify tumor oxidative stress, resulting in ROS-dependent tumor rejection. Herein we review the recent progresses regarding the impact of ROS on cancer cells and various immune cells in the TME, and discuss the emerging ROS-modulating strategies that can be used in combination with cancer immunotherapies to achieve enhanced antitumor effects.

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